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Chromosome 16p11.2 is one of the susceptible sites for recurrent copy number variations (CNVs) due to flanking near-identical segmental duplications. Five segmental duplications, named breakpoints 1 to 5 (BP1–BP5), have been defined as recombination hotspots within 16p11.2. Common CNVs on 16p11.2 include a proximal ~593 kb between BP4 and BP5, and a distal ~220 kb between BP2 and BP3. We performed a search for patients carrying 16p11.2 CNVs, as detected using chromosome microarray (CMA), in the Molecular Diagnostic Laboratory at the University of Texas Medical Branch (UTMB), in Galveston. From March 2013 through April 2018, a total of 1200 CMA results were generated for germline testing, and 14 patients tested positive for 16p11.2 CNVs, of whom 7 had proximal deletion, 2 had distal deletion, 4 had proximal duplication, and 1 had distal duplication. Herein, we provide detailed phenotype data for these patients. Our study results show that developmental delay, abnormal body weight, behavioral problems, and hypotonia are common phenotypes associated with 16p11.2 CNVs.

Background Familial chylomicronemia syndrome (FCS) is caused by a genetic defect in triglyceride (TG) metabolism that leads to severe hypertriglyceridemia, which in turn is associated with multiple morbidities and may cause severe pancreatitis that is both recurrent and progressive. Management of hypertriglyceridemia in FCS is challenging, as both dietary and medical interventions are often ineffective. Therapeutic plasma exchange (TPE) has been shown to rapidly decrease circulating levels of chylomicrons and TGs in patients presenting with acute hypertriglyceridemic-associated pancreatitis. Conversely, limited evidence exists to suggest that prophylactic use of TPE is effective at preventing recurrence of acute pancreatitis. Case report Herein, we report our experience with the use of chronic, prophylactic TPE to reduce the incidence of recurrent acute pancreatitis in a patient with FCS.

Background Crepidiastrum denticulatum (CD) is a well-known, traditionally consumed vegetable in Korea, which was recently reported to contain bioactive compounds with detoxification and antioxidant properties. Ischemia-reperfusion injury (IRI) is a major problem after renal transplantation. Furthermore, inflammatory responses to IRI exacerbate the resultant renal injury. In the present study, we investigated whether CD extract exhibits renoprotective effects against IR-induced acute kidney injury in mice. Materials and methods Renal IRI was induced in male C57BL/6 mice by bilateral renal pedicle occlusion for 30 minutes followed by reperfusion for 48 hours. CD extract (75 mg/kg) was administered orally 5 days before IRI. Results Treatment with CD extract significantly decreased blood urea nitrogen and serum creatinine levels as well as kidney tubular injury. CD also prevented IRI-induced renal glutathione depletion and increased malondialdehyde levels. Western blotting and reverse transcriptase polymerase chain reaction indicated that CD extract significantly attenuates inducible nitric oxide synthase and toll-like receptor 2/4 protein levels 48 h after IRI. The expression of tumor necrosis factor-α and interleukin-1β was significantly decreased in the CD extract treatment group. Conclusion CD extract improved acute renal IRI through its antioxidant and anti-inflammatory effects. These findings suggest that CD extract is a potential therapeutic agent for acute ischemia-induced renal damage.

Objectives This study was designed to evaluate the usefulness of intra-operative frozen section for the evaluation of microscopic extrathyroidal extension (ETE) in papillary thyroid carcinoma (PTC). Design Retrospective cohort study. Setting Dong-A University Medical Center, Busan, Korea. Participants Three hundred and sixty-four patients who underwent thyroid surgery from January 2000 to December 2010 with PTC confined to one unilateral lobe as diagnosed using preoperative ultrasonography were enrolled. Main outcome measures The patients who had microscopic ETE on frozen section were classified into “group A,” and those who did not have microscopic ETE on frozen section were classified into “group B.” Clinicopathologic factors including age, gender, size of the tumour, extent of operation, ETE, multifocality, bilaterality, lymph node metastasis and recurrence were compared between the two groups. Results Of the 364 patients enrolled, ETE was confirmed in 100 patients (group A, 27.5%) on frozen biopsy. The nodule size in group A (0.94±0.87 cm) was larger than that in group B (0.86±0.79 cm) (P=.042). In group A, 15 patients (15%) showed multifocality and 11 patients (14.47%) showed bilaterality. In group B, 37 patients (14.02%) showed multifocality and seven patients (43.35%) showed bilaterality. They did not differ significantly between the two groups (P=.811, P=.182). There was a higher frequency of lymph node metastases in group A (52/86, 60.47%) than in group B (7/16, 43.75%, P=.214). Recurrence was observed in only two patients who had received thyroid lobectomy as the initial surgery in group A. Conclusions Intra-operative frozen biopsy can be a useful method for identifying the microscopic ETE. During the surgery, it can also help the surgeon to decide the optimal extent of surgery and the need for central compartment neck dissection in PTC patients.

Introduction: We report a pediatric case of primary hyperparathyroidism due to a parathyroid adenoma and Cushing’s disease due to a pituitary adenoma. Clinical Case: The patient presented at 13.5 years old for hypertension that was discovered during an exam for weight loss, headaches, and paresthesias. Evaluation was significant for elevated blood pressure (148/98 mmHg), obesity (BMI 96.5%), striae, and he was found to be midpubertal. Tests showed calcium levels 10.7 (RR 8.6-10.6 mg/dL), aldosterone 2.4 (RR 4.0-31.0), and 24 hour urine cortisol/creatinine 451 ug/g (prepubertal RR< 25, >18 yo

Persistent mullerian duct syndrome (PMD) with antimullerian hormone (AMH) deficiency is usually associated with mutations or deletions of the AMH gene, although many cases have no identified gene association. We report on a genetic male with PMD and AMH deficiency associated with distal monosomy 10q. A term 3,230 g infant was born to a healthy 27-year-old. Fetal ultrasound had shown possible genital ambiguity. Postnatal exam showed a 0.5 cm phallus with basal meatus, normal scrotum with no palpable gonads, no vaginal orifice, and a rectal fistula with an imperforate anus. Voiding cystourethrogram with ultrasound, cystoscopy, and laparoscopy showed normal bladder, urethral orifice, distal vagina, cervix, and bilateral abdominal testis. At 24 hours of life, testosterone was within normal range with low AMH level. Chromosome microarray analysis showed 46, XY, del10(10q25.3q26.13) involving an 8.2 MB interstitial deletion. Whole exome sequencing identified a NOTCH2 variant (1p11.2). AMH sequencing revealed no abnormalities. Following multidisciplinary team and parent discussion, male gender was assigned. Testosterone treatment resulted in penile length of 1.5 cm. Bilateral orchiopexy and posterior sagittal anorectoplasty were performed at 11 months of age; rudimentary mullerian structures were identified. This observation suggests an association of 10qter elements with male differentiation including AMH expression and is similar to a patient with 46, XY, del(10q26.1) in which AMH levels were not reported. Regional candidate genes include FGFR2 (10q26.13). The possible contribution of a NOTCH2 variant cannot be excluded. © 2015 Wiley Periodicals, Inc.

Osteocalcin (OCN), a marker of osteoblast activity, has been implicated in the regulation of energy metabolism by the skeleton and thus may affect body fat measures. We examined the relationships of OCN to body fat measures and whether they vary according to markers of energy and vitamin D metabolism. Data was obtained from 58 obese adolescents aged 13–17.9 years (38 females, 8 black or African-American). We calculated total fat mass (FM) [dual X-ray absorptiometry (DXA)] and visceral adipose tissue (VAT) [computerized axial tomography (CT)]. Blood tests included leptin, OCN, 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), thyroid function tests, and triglycerides. Markers of glucose metabolism were obtained from fasting and OGTT samples. Adolescents with 25(OH)D

Background: Data on the relation between vitamin D status and body fat indexes in adolescence are lacking. Objective: The objective was to identify factors associated with vitamin D status and deficiency in obese adolescents to further evaluate the relation of body fat indexes to vitamin D status and deficiency. Design: Data from 58 obese adolescents were obtained. Visceral adipose tissue (VAT) was measured by computed tomography. Dual-energy X-ray absorptiometry was used to measure total bone mineral content, bone mineral density, body fat mass (FM), and lean mass. Relative measures of body fat were calculated. Blood tests included measurements of 25-hydroxyvitamin D [25(OH)D], parathyroid hormone (PTH), osteocalcin, type I collagen C-telopeptide, hormones, and metabolic factors. Vitamin D deficiency was defined as 25(OH)D 65 ng/mL. Results: The mean (±SD) age of the adolescents was 14.9 ± 1.4 y; 38 (66%) were female, and 8 (14%) were black. The mean (±SD) body mass index (in kg/m2) was 36 ± 5, FM was 40.0 ± 5.5%, and VAT was 12.4 ± 4.3%. Seventeen of the adolescents were vitamin D deficient, but none had elevated PTH concentrations. Bone mineral content and bone mineral density were within 2 SDs of national standards. In a multivariate analysis, 25(OH)D decreased by 0.46 ± 0.22 ng/mL per 1% increment in FM (β ± SE, P = 0.05), whereas PTH decreased by 0.78 ± 0.29 pg/mL per 1% increment in VAT (P = 0.01). Conclusions: To the best of our knowledge, our results show for the first time that obese adolescents with 25(OH)D deficiency, but without elevated PTH concentrations, have a bone mass within the range of national standards (±2 SD). The findings provide initial evidence that the distribution of fat may be associated with vitamin D status, but this relation may be dependent on metabolic factors. This study was registered at www.clinicaltrials.gov as {"type":"clinical-trial","attrs":{"text":"NCT00209482","term_id":"NCT00209482"}}NCT00209482, NCT00120146.

Objective: We report an unusual case of Prader-Willi Syndrome (PWS) presenting with clinical signs and symptoms suggestive of Angelman Syndrome (AS), without exclusive features of PWS.Methods: A deletion in the 15q11-13 region is associated with 2 distinctive genetic syndromes depending on the parent of origin: AS and PWS. AS is characterized by developmental delays, seizures, microcephaly, movement or balance disorders, speech disorders, and happy demeanor. PWS is characterized by hypotonia, hyperphagia, and developmental delays. An 11.5-year-old female was evaluated for developmental delay with cognitive disabilities, minimal speech, echolalia, and continuous hand motions. The patient had a pleasant but minimally interactive demeanor.Results: Chromosomal microarray analysis revealed a 5.02 Mb interstitial deletion of 15q11.2>q13.1 (base pairs 21,192,943 to 26,213,571), consistent with PWS or AS, and a 604 kb interstitial duplication of 16p11.2 (base pairs 29,530,197 to 30,134,432). Based on her presentation, AS was suspected; however, methylation analysis confirmed the diagnosis of PWS, with the presence of only the maternal copy of 15q11.2q13.1.Conclusion: Although variable phenotypic presentation of PWS has been reported, this case is particularly unusual in having only a few typical features of PWS while presenting as possible AS. We postulate that the 16p11.2 duplications, involving an autism susceptibility region, may have attenuated some features of PWS.Abbreviations: AS = Angelman Syndrome; ASD = Autism Spectrum Disorder; BMI = body mass index; CMA = chromosomal microarray; PWS = Prader-Willi Syndrome

Iron-overload associated endocrinopathy is the most frequently reported complication of chronic transfusion therapy in patients with thalassaemia (Thal). This study compared iron-overloaded subjects with Thal (n = 142; 54%M; age 25.8 +/- 8.1 years) and transfused sickle-cell disease (Tx-SCD; n = 199; 43%M, 24.9 +/- 13.2 years) to non-transfused SCD subjects (non-Tx-SCD; n = 64, 50%M, 25.3 +/- 11.3 years), to explore whether the underlying haemoglobinopathy influences the development of endocrinopathy. Subjects were recruited from 31 centres in the USA, Canada and the UK. Subjects with Thal had more evidence of diabetes (13% vs. 2%, P < 0.001), hypogonadism (40% vs. 4%, P < 0.001), hypothyroidism (10% vs. 2%, P =

Although it is life saving, transfusion therapy has resulted in the majority of sickle cell anemia and thalassemia patients being at risk for hemosiderosis-induced organ damage. It is unknown whether the complications of iron overload are affected by the underlying disease. In order to address this problem, we compared the prevalence of organ dysfunction in both groups of patients receiving chronic transfusion therapy (beta thalassemia, N = 30; sickle cell anemia, N = 43). Both groups had similar quantitative liver iron. Thalassemia patients had greater cardiac disease (20% vs. 0%), growth failure (27% vs. 9%), and endocrine failure (37% vs. 0%). The strongest predictors of combined endocrine and cardiac disease in multivariate analysis were duration of chronic transfusion (P = 0.03) and diagnosis (P = 0.03). Quantitative liver iron concentration on a single liver biopsy was not predictive of cardiac or endocrine injury. Viral hepatitis is the strongest predictor of hepatocellular damage (P = 0.009), while the development of liver fibrosis is more closely related to liver iron concentration (P = 0.04). In conclusion, sickle cell anemia and thalassemia differ in the prevalence of organ injury. This difference is related to the duration of iron exposure and the specific hemoglobinopathy. A prospective study with a larger number of subjects is needed to confirm the relationships between specific diagnosis, liver iron concentration over time, and organ dysfunction.

We report a case of a girl with clinical features of Peters' Plus Syndrome (PPS) (association of anterior eye chamber defects; peculiar facies; cleft lip/palate; brachymelia; developmental delay; growth retardation) and documented growth hormone deficiency (height -3.5 SDS at chronological age 5 years 8 months; low growth factors; bone age delay; growth velocity 4.4 cm/year (

Prader-Willi Syndrome (PWS), first described in 1956, is a unique genetic condition with a prevalence of 1 in 10,000 - 25,000. Features include severe lifelong hypotonia, insatiable appetite, short stature, obsessive-compulsive behaviour, morbid obesity, hypogonadism, kyphosis, scoliosis and osteoporosis. Studies beginning in the 1970s demonstrated that PWS is associated with a deficiency in growth hormone. Growth hormone treatment in children with PWS improves linear growth and more importantly leads to an increased muscle mass, bone mineral density and physical performance. In mid-2000, growth hormone became the first pharmaceutical approved in the US and Europe for the treatment of childhood PWS. It is now considered an essential part of comprehensive care for this condition. Ongoing studies address issues of growth hormone dosage, long-term efficacy, effects on neonatal and childhood growth and development and effects in adults with PWS.

The objective of this study was to examine the impact of crowding (stocking density) on food consumption and growth of juvenile Sepia officinalis reared at 17 and 25 °C. Two groups of 75 cuttlefish each were reared in closed seawater systems with water temperatures of 17 and 25 °C. Each group was subdivided into two treatments (three replicates per treatment): low-density (equivalent to 100 Sepia m−2) and high-density (equivalent to 400 Sepia m−2). Food consumption was measured daily and live wet body weight (g) was measured weekly over a 5-week study. The 25 °C treatment resulted in significantly higher growth rates and food consumption compared to the 17 °C treatment. Stocking density had no statistically significant effect on food consumption, gross growth efficiency (GGE), or weight at either temperature. However, the high-density treatments had slightly lower GGE values overall and growth in weight at 25 °C was slightly but consistently lower in the high-density treatment suggesting that stocking densities of 400 Sepia m−2 may be approaching levels that impact feeding and growth.

Introduction: The liver is the main source of serum insulin-like growth factors (IGFs) and IGF-binding proteins (IGFBPs) and the concentration of these proteins might reflect liver function. Methods: In a retrospective longitudinal study we examined serum levels of total and free IGF-I, IGF-II, IGFBP-1, IGFBP-2, IGFBP-3 and IGFBP-6 in 21 adult patients with end-stage liver disease before and after orthotopic liver transplantation (LTX) by sensitive and specific RIAs. In each patient, the mean value of at least three measurements before and after LTX was calculated. Results: Before LTX, serum levels of total and free IGF-I, IGF-II, IGFBP-3 were low and showed a rapid and significant increase in almost all patients after successful LTX (total IGF-I: 30 ± 7 vs. 256 ± 30 ng/ml, p < 0.001; free IGF-I: 1.3 ± 0.3 vs. 3.5 ± 0.6 ng/ml, p < 0.01; IGF-II: 177 ± 28 vs. 618 ± 30 ng/ml, p < 0.001; IGFBP-3: 1,230 ± 136 vs. 3,665 ± 264 ng/ml, p < 0.001). In contrast, IGFBP-1 was found to be high immediately before LTX, and declined to normal levels after LTX (210 ± 40 vs. 90 ± 15 ng/ml, p < 0.01), while IGFBP-2 did not show any significant changes (1,154 ± 296 vs. 1,303 ± 192 ng/ ml). Positive correlations were found between IGF-I, IGF-II or IGFBP-3, and serum pseudocholinesterase (R = 0.50, 0.72 and 0.61 respectively, p < 0.001). Negative correlations were found between IGF-I, IGF-II or IGFBP-3, and prothrombin time (R = 0.50, 0.59 and 0.51 respectively, p < 0.001). Conclusion: Patients with severe liver disease show decreased levels of total and free IGF-I, IGF-II and IGFBP-3, and increased levels of IGFBP-1. These abnormalities are promptly normalized after successful LTX. Thus, serum levels of IGF-I, IGF-II and IGFBP-3 might be useful parameters for the assessment of liver function.

Quantification of the acid-labile subunit (ALS) has to date been restricted to immunoassays utilizing polyclonal antibodies. By immunization with N-terminal and C-terminal specific ALS oligopeptides, we generated monoclonal antibodies (mAbs) that target ALS-specific sequences outside the nonspecific leucine-rich repeats in the ALS molecule. For mAb selection, a special screening method was developed. Monoclonal antibody 5C9, which targets the N-terminus of ALS, is immobilized and the anti-ALS mAb 7H3, directed against the C-terminus, is biotinylated and used as tracer Ab. Due to the extreme pH-lability of ALS, changes in immunorecognition of ALS were investigated after acidification for protein unfolding in different pH ranges and in a time-dependent manner. It was determined that acidification of the serum samples to pH 2.7 for 30 min, followed by neutralization and dilution to 1:100 was the optimal acid-neutralization method. For standardization purposes, a serum pool derived from healthy volunteers was assigned the value 1 U/ml ALS. The sandwich assay has a working range with a linear dose-response curve in a log/log system between 0.005 and 10 U/ml. ALS levels in seven acromegalic patients ranged from 2.0 to 4.2 U/ml, and in 12 untreated growth hormone deficient patients from 0.036 to 0.986 U/ml (mean=0.45 U/ml). After 12 months of growth hormone therapy, ALS levels increased significantly to 1.18+/-0.45 U/ml (mean+/-SD; p0.0006). The increase ranged from 0.48 to 1.4 U/ml. The change in ALS with growth hormone (GH) therapy correlated closer with the change in IGF-I (r=0.798, p=0.0057; Spearman rank correlation) than with the change in insulin-like growth factor binding protein (IGFBP3; r=0.549, p=0.057). This specific sandwich assay for the measurement of ALS provides a potentially valuable indicator of growth hormone secretory status. With this mAb-based immunofluorometric assay, the nonspecific detection of other proteins containing leucine-rich repeat sequences can be excluded.

Standard weight-for-age and height-for-age charts have been used for many years to assess growth and body compositions of children, including curves specific to the Prader-Willi syndrome (PWS). However, a number of direct measures of body compositions have been developed in recent years. Dural-energy x-ray absorptiometry (DXA) provides a measure of bone mineral content and bone mineral density for the whole body and at specific bone regions (spine, hip, forearm). This technology now has been extended to include assessment of the body's lean tissue mass and body fat mass. An alternate technique, called bioelectrical impedance analysis (BIA), has gained wide use in recent years as an indirect measure of the fat-free mass. The older, underwater weighing method is giving way to the air-displacement plethysmographic technique for assessing body fatness. Total body potassium still remains the method of choice for a direct assessment of body cell mass, and body nitrogen is recognized as the best assay for body protein mass. Imaging techniques, such as a computer tomography and magnetic resonance imaging, continue to receive increasing attention for body composition assays, especially for the subcutaneous vs. visceral distribution of body fat. Although total body water and extracellular water can be measured by dilution techniques, these methods are slowly being replaced by the BIA assay. When these various techniques are used in combination, the patient's nutritional status can be obtained based on a comprehensive 5-level multicompartment model of the body composition. Each of these methods will be reviewed, and their specific strengths and limitations presented, relative to their application for assessing changes in body composition of the PWS patient.▪ The Endocrinologist 2000; 10: 57S-62S

Prader-Willi syndrome (PWS) is a disabling condition characterized by hypotonia, hyperphagia, obesity, short stature, delayed or absent puberty, and mental retardation. The syndrome complex was first described in 1956 by Dr. Andrea Prader and colleagues [1]. In the 1980s, a characteristic genetic defect was identified involving deletion of paternal alleles at chromosome 15q11-13 [2-6]. This occurs by deletion of alleles on the paternal copy of chromosome 15q, an absent paternal chromosome 15q with maternal disomy, or, rarely, by mutations of the imprinting center of chromosome 15q. The estimated population prevalence of PWS is 1 in 15,000 live births.

Short stature, decreased muscle mass (hypotonia), increased body fat, decreased bone mineral density and other somatic abnormalities are major causes of morbidity and social limitation in individuals with Prader-Willi syndrome. Detailed studies indicate that two major endocrine pathologies may account for many of these somatic abnormalities. A true deficiency of the growth hormone (GH)-insulin-like growth factor axis is a principal cause of the short stature and is probably a major contributor to the decreased muscle mass and osteopenia. Hypogonadotropic hypogonadism is the probable primary cause of osteopenia and osteoporosis. No other endocrine abnormalities have been specifically identified in Prader-Willi syndrome, although there may be increased risks of premature adrenarche and type 2 diabetes mellitus, both secondary to obesity. GH replacement therapy is effective in normalizing linear growth and also has positive effects on muscle mass and function, and on bone mineralization. Judicious gonadal steroid replacement may be effective in treating the osteopenia and preventing osteoporosis. GH and gonadal steroid replacement therapy should be considered for all patients with Prader-Willi syndrome.

Activity-guided fractionation of the roots of Anthriscus sylvestris resulted in the isolation and characterization of five cytotoxic compounds, deoxypodophyllotoxin (1), falcarindiol (2), and angeloyl podophyllotoxin (5) from the hexane soluble fraction and morelensin (3), bursehernin (4) from the chloroform soluble fraction. It is the first report of the occurrence of compound 5 in nature.

Children with chronic renal failure (CRF) are often growth recarded despite normal serum levels of GH and insulin-like growth factors (IGFs). Recent studies suggest that excess IGF-binding proteins (IGFBPs) in the 35-kDa fractions of CRF serum contribute to CRF growth failure. This report characterizes the relationship between IGFBP-3 and IGF peptides in the serum of growth-retarded CRF children. Size-exclusion chromatography at pH 7.4 found IGFBP-3 and IGFs almost exclusively in the 150-kDa fractions of normal serum, where their molar stoichiometry was approximately 1:1. However, similar chromatography of CRF serum found a molar excess of IGFBP-3 over total IGFs in the 150-kDa fractions and large amounts of IGFs in the 35-kDa fractions. In the 150-kDa fractions of CRF serum, IGFBP-3 was present in normal amounts, but a greater than normal amount was in the form of a 29-kDa IGFBP-3 fragment. Treatment of these CRF children with recombinant human GH increased the molar excess of IGFBP-3 over total IGFs in the 150-kDa fractions, the amount of IGFBP-3 and total IGFs in the 150-kDa fractions, and the amount of IGFs, but not IGFBPs, in the 35-kDa fractions. These data suggest that in untreated CRF children, proteolysis of IGFBP-3 in the 150-kDa fractions releases IGFs to the excess IGFBPs in the 35-kDa fractions, but insufficient IGF is released to overcome the growth-inhibiting effects of these excess IGFBPs. Treatment with recombinant human GH increases levels of IGFs and IGFBP-3 in the 150-kDa fractions, and subsequent IGFBP-3 proteolysis releases sufficient IGF to overcome the growth inhibitory effects of excess IGFBPs in the 35-kDa fractions of CRF serum.

The activity of the hypothalamic-GH-insulin-like growth factor (IGF) network declines with age. It has recently been shown that increased cardiovascular mortality occurs in adults with GH deficiency. As hypercholesterolemia is common in GH-deficient adults, and because there is experimental evidence that GH may play a role in regulating plasma cholesterol, we decided to investigate the activity of the GH-IGF axis in an elderly population by measuring serum IGF-I, IGF-II, and IGF-binding protein-3 (IGFBP-3) levels and to study their relationship with blood lipid levels. One hundred and thirty-two elderly subjects, 52 men and 80 women, were studied (age range, 60–91 yr). Men had significantly lower levels of IGFBP-3, high density lipoprotein cholesterol (HDL-C) and apoprotein A1 (ApoA1) compared to the women, whereas IGF-I and IGF-II were only slightly lower. Using linear regression analysis, we observed an inverse relationship of age with IGF-I (r = −0.35; P < 0.001), IGF-II (r = 0.40; P < 0.001), IGFBP-3 (r = 0.52; P < 0.001), body mass index, and lipid levels. Univariate regression analysis showed a strong and positive correlation of both IGF-I and IGFBP-3 with HDL-C and ApoA1. Partial correlation analysis, after adjustment for age and body mass index, showed that IGFBP-3 and IGF-II were still significantly and positively related to HDL-C and ApoA1. Furthermore, a strong association was documented among IGF-I, IGF-II, and IGFBP-3. These data demonstrate that even in an elderly population, further aging is accompanied by a progressive decline in circulating IGF-I, IGF-II, and IGFBP-3, suggesting a continuing diminution of the GH-IGF axis throughout aging. Moreover, the strong correlation between HDL-C and an index of GH secretion, such as IGFBP-3, suggests that GH might play an important role in lipid metabolism in healthy elderly subjects.

Previous studies suggest that growth retardation in children with chronic renal failure (CRF) results in part from inhibition of insulin-like growth factor (IGF) action by excess serum IGF-binding proteins (IGFBPs). Excess IGFBPs in CRF serum include IGFBP-1, -2, and -3 and a diffuse approximately 24- to 28-kDa IGFBP band identified by [125I]IGF ligand blot. The present studies characterized this diffuse approximately 24- to 28-kDa band. Initial studies identified this band as IGFBP-6, because it was immunoprecipitated by antiserum raised against a synthetic peptide of human IGFBP-6 (hIGFBP-6). Additional [125I]IGF ligand blots found that the immunoprecipitated band was 1) recognized by [125I]IGF-II but not [125I]IGF-1, 2) more abundant in CRF than in normal serum, and 3) more abundant in serum from dialyzed than nondialyzed prepubertal CRF children. Using the hIGFBP-6 antiserum in a specific and sensitive RIA, we found that serum IGFBP-6 levels were 4.7 +/- 1.7 nmol/L in 10 normal prepubertal children, 21.4 +/- 6.1 nmol/L in 44 nondialyzed prepubertal CRF children, 73.5 +/- 14.4 nmol/L in 7 dialyzed prepubertal CRF children, and 94.6 +/- 26.2 nmol/L in 14 dialyzed pubertal CRF children. IGFBP-6 levels were also elevated in 71 nondialyzed European children with CRF. In nondialyzed CRF children, serum IGFBP-6 levels 1) correlated inversely with the glomerular filtration rate, 2) did not correlate with height SD score, and 3) were not altered by 12 months of daily recombinant hGH treatment. In summary, a specific antiserum and RIA were used to demonstrate elevated levels of intact IGF-II-binding IGFBP-6 in serum of CRF children. We postulate that the excess IGFBP-6 may modulate the action of IGF-II on target tissues.

Children with chronic renal failure (CRF) have normal or high serum levels of GH, IGF-I, and IGF-II. Despite this, the serum of CRF patients has low IGF bioactivity, which may contribute to CRF growth failure. Recent studies suggest that excess IGF binding proteins (IGFBPs) in the approximately 35-kD fractions of CRF serum contribute to this low IGF bioactivity. This report characterizes a 29-kD form of IGFBP-3, IGFBP-3(29), which accumulates in the approximately 35-kD fractions of CRF serum and peritoneal dialysate. Deglycosylation and [125I]IGF ligand blot studies show that IGFBP-3(29) is a glycosylated IGFBP-3 fragment with low affinity for IGF peptides. Using an IGFBP-3 antibody column, IGFBP-3(29) was purified to homogeneity from the approximately 35-kD fractions of peritoneal dialysate from children with CRF. Compared with native IGFBP-3, pure IGFBP-3(29) has a 4-10-fold lower affinity for IGF-II and a 200-fold lower affinity for IGF-I. Consistent with the binding data, IGFBP-3(29) inhibited IGF-II-stimulated thymidine incorporation in chondrosarcoma cells, but was a less potent inhibitor than native IGFBP-3; also, native IGFBP-3 clearly inhibited IGF-I-stimulated thymidine incorporation in chondrosarcoma cells and potentiated IGF-I-stimulated aminoisobutyric acid uptake in bovine fibroblasts, but higher concentrations of IGFBP-3(29) had no effect on these IGF-I actions. Thus, the 29-kD IGFBP-3 form that accumulates in CRF serum and extravascular spaces is an IGFBP-3 fragment that may modulate IGF-II, but not IGF-I, effects on target tissues. Whether IGFBP-3(29) plays any role in the growth failure of children with CRF remains to be determined.

OBJECTIVE: In normal subjects, the major form of circulating IGF is the GH-dependent 150 kDa complex. The liver appears to be the main source of the three components of the 150 kDa complex and, in particular, hepatocytes synthesize the insulin-like growth factor (IGF) peptide and the acid-labile subunit (ALS), whereas Kupffer and sinusoidal endothelial cells produce IGF-binding protein-3 (IGFBG-3). We have studied the effects of the somatostatin analog octreotide, IGF-II des(1-3)IGF-I, transforming growth factor (TGF)-beta 1 and tri-iodothyronine (T3) on ALS secretion into the medium conditioned by rat hepatocytes in primary culture. METHODS: The regulation of ALS release was evaluated in the conditioned medium of adult rat hepatocytes exposed to increasing concentrations of test substances or to vehicle alone (control), after gel filtration in basic conditions, by immunoblot using an antiserum generated against the N-terminal 34 amino acids of human ALS. RESULTS: The results demonstrate that: 1) octreotide in vitro produces a dose-dependent inhibition of both basal and GH-stimulated ALS secretion into the hepatocyte conditioned medium; 2) the release of ALS by adult rat hepatocytes is not affected by the presence during the incubation of des(1-3)IGF-I or IGF-II; 3) an inhibitory effect, although only with very high doses, can be observed after treatment with TGF-beta 1; and 4) a small but significant increase of ALS released into the medium can be seen when hepatocytes are treated with T3. CONCLUSIONS: Evaluation of the effect of substances known to affect the production of IGF peptides, the IGFBPs, or both, on adult rat hepatocytes in primary culture revealed no powerful stimulator, but instead a potent inhibitor of ALS release/synthesis. Our data suggest that the effect of somatostatin on the 150 kDa complex is mediated not only by the reduction in GH concentration, but also by a direct inhibition of ALS release or synthesis.

The in vivo physiological relationships among GH, the insulin-like growth factors (IGFs), and the IGF-binding proteins (IGFBPs) are not completely defined, and single random measurements of these serum proteins do not completely reveal their dynamic relationships. We report the kinetic responses of the IGFs and IGF-binding proteins to exogenous GH in 23 subjects with untreated GH deficiency [5 women and 18 men; age, 15.0 +/- 6.2 yr (+/- s.d.), height z-score = -4.4 +/- 2.2 (+/- s.d.); body mass index = 19.3 +/- 2.4 kg/m2]. After an overnight fast, subjects were given a sc dose of recombinant human GH (2.85 i.u./m2), and blood was sampled from an indwelling peripheral venous catheter 0, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, and 24 h after the injection. Subjects were then treated with recombinant human GH (2.85 i.u./m2.day); fasting samples were obtained at 3 months (n = 22), and timed sampling was repeated at 6 months (n = 21). Fasting levels of IGF-I, free IGF-I, IGF-II, IGFBP-3, and insulin increased significantly within 3 months of GH treatment, whereas IGFBP-1, IGFBP-2, and IGFBP-6 showed no change. In the timed sampling studies at 0 and 6 months, GH levels peaked 3 h after treatment; the degree of rise and the rate of decline were both greater at 6 months. IGF-I levels increased beginning at 4 h, continuing throughout the 24-h period at month 0, whereas a plateau was observed after 6-8 h during the 6-month study. Free IGF-I paralleled total IGF-I except during fasting, when it varied inversely with IGFBP-1. IGFBP-3 and IGF-II both showed late (> 20 h) responses to a dose of GH, whereas IGFBP-2 and IGFBP-6 showed minimal changes. IGFBP-1 varied inversely with insulin, which, in turn, varied with meal intake. Comparative studies in 2 subjects with GH receptor deficiency showed no response to exogenous GH. However, both IGFBP-1 and IGFBP-2 were several-fold elevated, and IGFBP-1 varied inversely with the low insulin levels. Our data are the first to examine multiple elements of the serum IGF system in response to GH in both GH-deficient and replete states. The relationships of the different response patterns provide insight into the physiology of this system and may guide future studies.

Modulation of growth factors by growth hormone in children with chronic renal failure. Anthropometric measurements and circulating growth factors were studied serially in 44 prepubertal children with growth failure and chronic renal failure (GFR = 10 to 40 ml/min/1.73m2) who were randomized to receive either recombinant human growth hormone (rhGH; N = 30) or no treatment (N = 14). RhGH was given as Nutropin, 0.05 mg/kg/day, and the studies were carried out at baseline and after 3 and 12 months. At baseline, serum insulin-like growth factor binding protein (IGFBP)-1 and -2 levels were, while IGFBP-3 levels were not, higher than those of children with normal renal function. In addition, height SDS at baseline correlated inversely with serum IGFBP-2 levels (r = -0.461, P = 0.0016), but did not correlate significantly with any other factor. After 12 months of study, the 30 children receiving rhGH showed: (i) greater increase in height (9.1 ± 2.8 vs. 5.5 ± 1.9 cm, P < 0.0001); (ii) increases in serum levels of IGF-I, IGF-II, free IGF-I, IGFBP-3 and acid labile subunit (ALS); (iii) a greater decrease in serum IGFBP-1 levels; and (iv) no significant difference in serum IGFBP-2 levels, when compared to the 14 control patients. The change in height SDS after 12 months of rhGH (+ 0.8) in the 30 treated children correlated significantly and positively with serum ALS, IGFBP-3, total IGF, IGF-I, IGF-II and free IGF-I levels measured during treatment. These observations suggest that, in children with growth failure associated with chronic renal failure: (i) IGFBP-2, and not IGFBP-3, is likely to be a growth inhibitor; (ii) rhGH stimulates catch-up growth in part by increasing serum levels of IGF peptides; and (iii) linear growth is influenced by the balance between growth stimulating IGFs and growth inhibitory IGFBPs.

Weight loss is a common, persistent characteristic of long term human immunodeficiency virus (HIV-1) infection; its full etiology remains unknown. Because treatment with GH has induced nitrogen retention in various catabolic conditions, we designed this study to determine whether a moderate dose of insulin-like growth factor I (IGF-I) combined with a low GH dose could impede the catabolic response seen in HIV-1 infection. A double blind, placebo-controlled study design was used. Subjects in the GH/IGF-I treatment group (n = 44) and control group (n = 22) continued to receive their routine stable antiretroviral therapy. No patient had a recent history of opportunistic infection, malignancy, or Kaposi's sarcoma and had dietary intakes of at least 25 Cal/kg weight.day at study entry. During the 12-week study period, dietary instruction was given, and subjects were encouraged to maintain an intake of 35 Cal/kg and 1 g protein/kg. All subjects had a body mass index of 19.8 kg/m2 or less at the time of study entry or a weight loss of 10% or more of their premorbid weight and a body mass index below 26.1 kg/m2. The treatment group received 0.34 mg (0.68 mg/day) GH, twice daily, and 5.0 mg (10 mg/day) IGF-I, twice daily. Changes in body composition of total body potassium (TBK), total body nitrogen (TBN), fat-free mass (FFM), and body fat (Fat) were examined at 6 and 12 weeks during the treatment period. TBK, TBN, FFM, and Fat for the treatment and placebo groups were, on the average, below normal at study entry. At 6 weeks, the GH/IGF-I group showed a significant increase in FFM (P0.0001), a minimal increase in TBK (P0.05), and a substantial decrease in Fat (P0.01) compared with baseline values. The loss of body fat continued to be significant (P0.01) in the GH/IGF-I group treatment at 12 weeks, whereas the increase in FFM was minimal (P0.05). No significant changes in the mean body composition occurred at 6 or 12 weeks in the placebo group. By 12 weeks, neither TBK (body cell mass) nor TBN (total protein mass) had significantly increased relative to the values at baseline, although the FFM remained elevated. Thus, the combined GH and IGF-I doses used in this study in adult males with HIV-associated weight loss were ineffective in producing a sustained anabolic response and, in fact, resulted primarily in a significant loss of body fat.

Children with chronic renal failure (CRF) often fail to attain an adult height consistent with their genetic potential. The growth hormone (GH)/insulin-like growth factor (IGF)/growth plate chondrocyte axis has been intensively studied in these children to determine the basis for this growth failure. Evidence suggests that hepatic GH resistance results in deficient expression of IGF-I. However, serum IGF-I levels are usually normal and it is IGF-I action on target tissues which is inhibited, possibly by the presence of excess high-affinity IGF binding proteins (IGFBPs) in CRF serum. In this paper we evaluate the roles of IGFBP-1, -2, and -3 as growth inhibitors in CRF children. The data support a role for each of these IGFBPs as growth inhibitors. Currently, IGFBP-1 meets most criteria expected of a growth inhibitor, but IGFBP-2 and -3 will likely also meet these criteria and may well be important contributors to the growth failure of CRF. Ultimately, many or all of the six IGFBPs may be found to contribute to the excess high-affinity IGF binding sites which are a hallmark of CRF serum and are possible contributors to the growth failure of CRF children.

We report the development of a unique radioimmunoassay (RIA) for rat insulin-like growth factor-I (rIGF-I) which does not recognize human IGF-I (hIGF-I). The rIGF RIA uses a specific anti-rIGF-I antiserum with rIGF-I standards and radioligand. Rat sera were extracted by either an abbreviated acid/ethanol procedure or by acid-chromatography with virtually identical results. Assay sensitivity is congruent to 0.5 ng/tube and inter- and intra-assay coefficients of variation were 3.4-7.6% and 4.8-9.2%, respectively. Comparisons of the rIGF-I RIA with a typical heterologous RIA shows that the latter underestimates rIGF-I levels congruent to of 3-fold. Sera from rats treated with hIGF-I were also studied using the rIGF-I RIA and a hIGF-I- specific immunoradiometric assay (IRMA), and results indicate poor correlation between the actual total IGF-I levels (rIGF-I RIA + hIGF-IRMA) and the heterologous RIA estimates. The availability of both rIGF-I and hIGF-I specific immunoassays facilitates more precise studies of hIGF-I in the rat model.

Insulin-like growth factors I and II (IGF-I and II) are present in serum primarily within a ternary complex consisting of IGF, IGF-binding protein-3 (IGF-3) and acid-labile subunit (ALS). Relatively little is known about ALS as compared to the other components of the complex. We report immunoblot studies of ALS using a new rabbit antiserum to human ALS1-34. The antiserum shows high specificity for ALS, labelling only the intact 82-88 kDa doublet in whole serum. Treatment with endoglycosidase-F leads to only a partial deglycosylation of ALS in whole serum, while purified ALS is reduced to M(r) approximately 58 kDa. Acidification of both whole serum and purified ALS leads to a complete loss of ALS ability to bind to cross-linked IGFBP-3:[125I]IGF-II tracer; however, immunoblot studies show no change in the apparent M(r) of the major ALS band. Immunoblot studies of human serum shows that intact ALS is decreased in growth-hormone (GH) deficiency, increases with GH treatment, is elevated in GH excess and is unchanged with IGF-I treatment. These data provide new information regarding the characteristics of ALS and demonstrate the research utility of a highly-specific antiserum for this protein.

Insulin-like growth factor-binding protein (IGFBP)-1 is one of six homologous proteins that specifically bind and modulate the mitogenic and metabolic actions of insulin-like growth factor (IGF)-I and IGF-II. Of the six IGFBP, IGFBP-1 is the only one that displays rapid dynamic regulation in vivo, with serum levels varying 10-fold or more in relation to meals. The complementary cDNA for IGFBP-1 was first reported in 1988. The predicted 234-amino acid sequence has a molecular mass of 25.3 kDa. The N-terminal and C-terminal regions are highly homologous among rat, human, and bovine sequences, and contain 18 conserved cysteines which are postulated to provide a framework for ligand binding. The 65-residue midregion is less homologous and does not contain cysteines, but does include a Pro-Glu-Ser-Thr (PEST) domain that is typical of rapidly metabolized proteins. The gene for IGFBP-1 has been localized to human chromosome region 7p12-p14, where it is contiguous with the gene for IGFBP-3. IGFBP-1 mRNA and protein expression have been identified in human liver and uterine decidua, and in nonhuman kidney. In vitro and in vivo studies indicate that insulin is the primary regulator of IGFBP-1 expression in these tissues, and that the primary effect of insulin is rapid inhibition of transcription. On the other hand, cortisol, glucagon, and cAMP stimulate IGFBP-1 production. Limited data also show a potent stimulatory effect of phorbol esters. A detailed review of IGFBP-1 levels and physiology in vivo and in vitro is presented. The function of IGFBP-1 is not completely defined. However, several studies demonstrate that IGFBP-1 inhibits IGF binding to cell surface receptors and thereby inhibits IGF-mediated mitogenic and cell metabolic actions. Furthermore, IGFBP-1 regulation by insulin and glucoregulatory hormones in vitro and limited in vivo data are consistent with a role for IGFBP-1 in glucose counterregulation.

In hepatocytes, insulin-like growth factor-binding protein-1 (IGFBP-1) levels are increased by glucocorticoids and by agents that raise intracellular cAMP levels such as glucagon, theophylline, forskolin, and cAMP analogues. In contrast, insulin lowers IGFBP-1 levels, an effect dominant over the glucocorticoid and cAMP effects. Previous studies showed that dibutyryl cAMP (Bt2cAMP) and theophylline increase IGFBP-1 promoter activity in HEP G2 human hepatoma cells and that insulin abolishes this increase. In studies reported here, HEP G2 cells were used to further evaluate the role of cAMP in stimulating IGFBP-1 expression. Initial studies found that either 0.5 or 5.0 mM Bt2cAMP alone, or the combination of 0.5 mM Bt2cAMP and 2 mM theophylline, increased IGFBP-1 protein levels, mRNA levels, and promoter activity, but that the addition of theophylline to Bt2cAMP was required to give a approximately 5-fold increase in promoter activity. Deletion mutations of the IGFBP-1 promoter were used to show that much of the effect of Bt2cAMP and theophylline was conferred by the region between 269 and 246 base pairs (bp) 5' of the IGFBP-1 mRNA cap site. DNase I protection assays showed that HEP G2 nuclear extract footprinted the region from 273 to 249 bp 5' of the cap site; this region, designated P2, has a central CGTCA motif common to cAMP-responsive elements (CREs). Mutating the CGTCA motif in the 1205-bp IGFBP-1 promoter construct to TAGCA led to a 51% decrease in the ability of Bt2cAMP and theophylline to stimulate IGFBP-1 promoter activity above control levels. In addition, cotransfection of the catalytic subunit of cAMP-dependent protein kinase A (PKA) with the native 1205-bp IGFBP-1 promoter construct stimulated IGFBP-1 promoter activity 3.9-fold, but the TAGCA mutation decreased by 73% the ability of PKA to stimulate IGFBP-1 promoter activity above control levels. Mutating the CGTCA motif to TAGCA also blocked the ability of both crude HEP G2 nuclear extract and recombinant CRE-binding protein to bind to the P2 element. These data suggest that the P2 element is a CRE that confers at least part of the stimulatory effect of cAMP on the human IGFBP-1 promoter.

Insulin-like growth factor-binding protein-1 (IGFBP-1) is one of several related proteins that bind and modulate the actions of IGFs. The liver is the primary source of IGFBP-1, and insulin is a major regulator of hepatic IGFBP-1 production. We report five sets of investigations that further define the characteristics of hepatic IGFBP-1 response to insulin. In normal subjects, a continuous high-dose insulin infusion caused a rapid decrease in plasma IGFBP-1 concentrations, with a rate of 0.24 ± 0.04 μg/L·min−1 and a t 1 2 of 89 ± 4 minutes. Conversely, a 3-hour somatostatin (SRIF) infusion caused a 4.5-fold increase in plasma IGFBP-1 levels. SRIF plus low-dose insulin infusion (to inhibit break-through insulin secretion) resulted in a plateau in IGFBP-1 concentrations at 5 to 8 hours, with a t 1 2 to achieve steady state of 60 to 75 minutes. Under similar conditions, a stepped increase in plasma glucose level from 5 to 9 mmol/L had no effect on the rate of IGFBP-1 increase in plasma, indicating that an acute increase in glucose concentration within a physiologic range has no independent inhibitory effect on IGFBP-1 production in the presence of a nonsuppressive insulin level. Using SRIF plus sequential graded insulin infusions, the threshold peripheral (=portal) plasma insulin concentration for IGFBP-1 suppression was between 65 and 172 pmol/L. Subjects with insulin-dependent diabetes mellitus (IDDM) showed a similar dose-response pattern, suggesting that insulin regulation of IGFBP-1 may be normal in IDDM. The rapid and sensitive response of IGFBP-1 to insulin is consistent with its postulated role to modulate IGF bioaction in relation to substrate availability. Moreover, measurement of plasma IGFBP-1 concentrations may serve as a useful marker of hepatic insulin sensitivity.

Background Metformin has been proffered as a therapy for adolescent obesity, although long-term controlled studies have not been reported. Objective To test the hypothesis that 48 weeks of daily metformin hydrochloride extended release (XR) therapy will reduce body mass index (BMI) in obese adolescents, as compared with placebo. Design Multicenter, randomized, double-blind, placebo-controlled clinical trial. Setting The 6 centers of the Glaser Pediatric Research Network from October 2003 to August 2007. Participants Obese (BMI > or = 95th percentile) adolescents (aged 13-18 years) were randomly assigned to the intervention (n = 39) or placebo groups. Intervention Following a 1-month run-in period, subjects following a lifestyle intervention program were randomized 1:1 to 48 weeks' treatment with metformin hydrochloride XR, 2000 mg once daily, or an identical placebo. Subjects were monitored for an additional 48 weeks. Main Outcome Measure Change in BMI, adjusted for site, sex, race, ethnicity, and age and metformin vs placebo. Results After 48 weeks, mean (SE) adjusted BMI increased 0.2 (0.5) in the placebo group and decreased 0.9 (0.5) in the metformin XR group (P = .03). This difference persisted for 12 to 24 weeks after cessation of treatment. No significant effects of metformin on body composition, abdominal fat, or insulin indices were observed. Conclusion Metformin XR caused a small but statistically significant decrease in BMI when added to a lifestyle intervention program. Trial registration clinicaltrials.gov Identifiers: NCT00209482 and NCT00120146.

Insulin-like growth factor binding protein-1 (IGFBP-1) is a liver-derived protein that modulates the mitogenic actions of the insulin-like growth factors (IGFs). IGFBP-1 production is potently inhibited by insulin both in vivo and in HepG2 human hepatoma cells. To further define the pathways of IGFBP-1 regulation, we studied the effects of modulators of protein kinase-C (PKC) on HepG2 cell IGFBP-1 production. Phorbol 12-myristate 13-acetate (PMA) stimulated IGFBP-1 production in a time- and dose-dependent manner, with maximal stimulation occurring at 10-100 nmol/L. The degree of stimulation was dependent on cell density, ranging from about 2-fold in confluent to more than 10-fold in sparse cultures. Preincubation with PMA abolished the inhibitory effect of insulin, while preincubation with insulin did not inhibit PMA stimulation. The transient PKC activator diC8 had no effect, while studies with the PKC inhibitors sphinganine and H-7 were limited by solvent vehicle cytotoxicity. Staurosporine (STS), a potent PKC inhibitor, stimulated IGFBP-1 production 2- to 4-fold and augmented the stimulatory effect of PMA. Concanavalin-A, an inhibitor of PMA-stimulated PKC translocation and down-regulation, inhibited the effects of PMA and STS. Our findings indicate that PKC is involved in the regulation of hepatic IGFBP-1 production. The effects of PMA, which causes rapid activation, followed by membrane translocation and down-regulation of PKC, are similar to those of STS and are countered by Concanavalin-A. These data suggest that PKC activity may mediate tonic inhibition of IGFBP-1 production, while PKC downregulation stimulates the production of this regulatory protein.

Insulin is the principal regulator of hepatic insulin-like growth factor binding protein-1 (IGFBP-1) production, mediating the rapid decrease in plasma IGFBP-1 in response to nutritional intake. In this study, we defined IGFBP-1 regulation by insulin in upper and lower body obesity, conditions associated with insulin resistance and chronic hyperinsulinemia. Overnight postabsorptive IGFBP-1 levels in obese and nonobese women showed an inverse, nonlinear relationship with plasma insulin concentrations. Maximum suppression of IGFBP-1 was seen at 70-90 pmol/L plasma insulin. Both groups of obese women had mean fasting plasma insulin concentrations above this threshold level and, consequently, markedly suppressed IGFBP-1 levels. To assess the dynamics of insulin regulated IGFBP-1, 10 obese and 8 nonobese women were studied during sequential saline infusion (0-90 min), hyperinsulinemia (insulin infusion; 90-210 min) and hypoinsulinemia (somatostatin + GH infusion; 210-330 min). Insulin infusion rapidly decreased plasma IGFBP-1 levels in nonobese subjects (60% decrease in 2 h), but had little or no further suppressive effect in obese subjects. Complete insulin withdrawal resulted in a significant rise in plasma IGFBP-1 concentrations in all subjects, but the response was blunted in obese compared to nonobese groups. In contrast to plasma IGFBP-1, IGF-I concentrations did not vary during hyper- and hypoinsulinemic infusion periods and were not significantly different between groups. Basal GH levels were significantly higher in nonobese when compared to obese women, but did not change with infusions. In conclusion, low IGFBP-1 levels in obesity are related to elevated insulin levels which are, in turn, related to body fat distribution and insulin resistance. The chronically depressed levels of IGFBP-1 may promote IGF bioactivity as well as its feedback regulation of GH secretion, thus contributing to the metabolic and mitogenic consequences of obesity. In addition, our findings imply that hepatic insulin sensitivity in terms of IGFBP-1 production is preserved despite peripheral insulin resistance in obesity.

We examined the relationships between 4 glycated protein assays and home blood glucose monitoring (HBGM) in 26 children with poorly-controlled insulin-dependent diabetes mellitus (IDDM) during a period of improved management. At 2 week intervals for 6 visits (12 weeks in total), HBGM records were collected and a blood sample was obtained for measurement of glycated proteins and glucose. Assays included glycated hemoglobin (GHb) and glycated serum proteins (GP) by boronate affinity chromatography, hemoglobin A 1 C by PolyCAT A high performance liquid chromatography (HAC) and fructosamine (FA). All 4 glycated protein levels declined significantly over the 12 week period. Significant correlations between the glycated proteins and HBGM were observed over 2 week intervals. None of the 4 assays were affected by the glucose level in the sample. Changes in mean HBGM readings over 2 week intervals were correlated with both FA and GP with wide prediction intervals. Over cumulative 2 week intervals, which may more accurately reflect longitudinal trends, all 4 glycated proteins were correlated with mean HBGM readings. At each cumulative interval, GHb and GP showed the largest variation with MBG, while FA showed the least variation with MBG. Our data indicate that of the 4 assays tested, FA has limited clinical value as compared to other glycated protein assays, whereas assays based on boronate affinity chromatography (GHb and GP) provide the most useful clinical indicators of short-term changes in glycemic control. The clinical utility of a new HPLC method for determination of glycated hemoglobins is also demonstrated.

Insulin rapidly lowers serum insulin-like growth factor-binding protein-1 (IGFBP-1) levels in vivo. In studies reported here, HEP G2 cells were used as a model system to investigate how insulin achieves this effect. When HEP G2 cells were incubated with 100 nM insulin for 6, 14, or 24 h, IGFBP-1 protein levels in conditioned medium fell to approximately 50% of control values. This apparently was due to a fall in the rate of IGFBP-1 protein synthesis, since HEP G2 cells incorporated 46% less [35S]methionine into IGFBP-1 during a 4-h incubation with 100 nM insulin. IGFBP-1 mRNA levels were similarly affected by 100 nM insulin, falling to 45% of control values after 2 h, and to 9% of control values after 4 h of incubation with this hormone. The fall in IGFBP-1 mRNA level is consistent with data from nuclear transcription assays. HEP G2 nuclei isolated from cells that were incubated with 100 nM insulin for 2 h synthesized only approximately 1/3 the number of IGFBP-1 transcripts as did control nuclei. Further evidence that insulin decreases IGFBP-1 gene transcription comes from transient transfections using chimeric IGFBP-1 promoter-chloramphenicol acetyltransferase reporter gene constructs. IGFBP-1 promoter activity fell to approximately 50% of control values when HEP G2 cells transfected with a construct containing the first 1205 base pairs of the IGFBP-1 promoter were incubated with 100 nM insulin for 6, 14, or 24 h. Insulin lowered both IGFBP-1 protein levels and promoter activity in a dose-dependent manner. A half-maximal effect was found at approximately 1 nM insulin and a maximal effect was found at approximately 10 nM insulin in each instance. Transfections with constructs containing smaller IGFBP-1 promoter fragments showed that the region spanning from 103 to 529 base pairs 5' to the IGFBP-1 mRNA cap site was necessary to demonstrate the inhibitory effect of insulin. These studies indicate that insulin lowers IGFBP-1 protein levels, at least in part, by rapidly decreasing the rate of IGFBP-1 gene transcription, and suggest that this insulin-mediated fall in transcription is conferred through a specific region of the IGFBP-1 promoter.

GH replacement in Prader-Willi syndrome (PWS) children has well-defined benefits and risks and is used extensively worldwide. Its use in PWS adults has been limited by documentation of benefits and risks, as determined by larger multisite studies.Our objective was to evaluate the effectiveness and safety of GH in GH-deficient genotype-positive PWS adults.We conducted a 12-month open-label multicenter trial with 6-month dose-optimization and 6-month stable treatment periods.The study was conducted at outpatient treatment facilities at four U.S. academic medical centers.Lean and obese PWS adults with diverse cognitive skills, behavioral traits, and living arrangements were recruited from clinical populations.Human recombinant GH (Genotropin) was initiated at 0.2 mg/d with monthly 0.2-mg increments to a maximum 1.0 mg/d, as tolerated.Lean body mass and percent fat were measured by dual-energy x-ray absorptiometry.Lean body mass increased from 42.65 +/- 2.25 (se) to 45.47 +/- 2.31 kg (Por = 0.0001), and percent fat decreased from 42.84 +/- 1.12 to 39.95 +/- 1.34% (P = 0.025) at a median final dose of 0.6 mg/d in 30 study subjects who completed 6-12 months of GH. Mean fasting glucose of 85.3 +/- 3.4 mg/dl, hemoglobin A1c of 5.5 +/- 0.2%, fasting insulin of 5.3 +/- 0.6 microU/ml, area under the curve for insulin of 60.4 +/- 7.5 microU/ml, and homeostasis model assessment of insulin resistance of 1.1 +/- 0.2 were normal at baseline in 38 study initiators, including five diabetics, and remained in normal range. Total T(3) increased 26.7% from 127.0 +/- 7.8 to 150.5 +/- 7.8 ng/dl (P = 0.021) with normalization in all subjects, including six (20%) with baseline T(3) values at least 2 sd below the mean. Mildly progressive ankle edema was the most serious treatment-emergent adverse event (five patients).This multicenter study demonstrates that GH improves body composition, normalizes T(3), and is well tolerated without glucose impairment in PWS genotype adults.

Insulinlike growth factor binding protein 1 (IGFBP-1) has been shown to modulate the metabolic and mitogenic actions of the growth hormone (GH)- dependent peptide insulinlike growth factor I. Previous studies showed that levels of IGFBP-1 are regulated by insulin. The relative role of GH in the regulation of IGFBP-1 levels is less well defined and was examined in our study with a contiguous two-part protocol. Overnight (part A) and pre- and post-morning meal (part B) blood samples were obtained from eight healthy adults during a constant infusion of saline (SAL) or 4 μg · kg−1 · min−1 GH. Five of eight subjects were restudied with glucose (GLUC) infused during part B (SAL + GLUC) to match glucose and insulin to levels observed during GH infusion. During SAL infusion, IGFBP-1 levels measured by specific radioimmunoassay showed a marked immediate decline after the evening meal in part A, with a subsequent nocturnal rise of 2.4- to 17.3-fold. GH infusion resulted in a similar meal-induced fall in IGFBP-1 levels but led to a delayed nocturnal rise in IGFBP-1, which was associated with elevated postprandial insulin concentrations. During part B, changes in plasma IGFBP-1 levels showed a similar pattern, with a delayed postprandial increase observed during both GH and SAL + GLUC infusions. The half-life of IGFBP-1 disappearance was calculated at ∼2 h for all three infusion groups. Comparison of venous and arterialized blood samples showed no consistent pattern of difference, arguing against peripheral tissue clearance or compartmentalization as the mechanism for the rapid rise and fall in IGFBP-1 levels. Our studies, the first to measure GH, insulin, and glucose in concurrent sampling and under controlled physiological conditions, support previous investigations suggesting that insulin (not GH or glucose) is the primary regulator of plasma IGFBP-1 levels. Furthermore, we postulate that the observed fluctuations in plasma levels are caused by a direct insulin effect on hepatic IGFBP-1 production.

A human hepatoma cell line, HepG2, secretes a discrete insulin-like growth factor-binding protein (IGFBP-1) into serum-free medium, which is identical to the 25K mol wt BP in amniotic fluid and plasma. IGFBP-1 levels in vivo have been shown to be inversely correlated with circulating insulin concentrations. This study investigated the direct effects of insulin on IGFBP-1 production in vitro. Addition of insulin to HepG2 cultures induced a rapid dose-dependent decrease in IGFBP-1 synthesis and secretion independent of the glucose concentration in the medium. As assessed by ligand binding and specific RIA, levels of IGFBP-1 were 20-50% of control levels in 18-h conditioned medium from insulin-treated cells. Monoclonal antibody studies indicated that the suppressive effect of insulin on IGFBP-1 synthesis was mediated through specific interaction with the insulin receptor. Therefore, HepG2 cells respond to insulin by altering the synthesis and secretion of IGFBP-1 in a manner that mimics many of the changes in plasma IGFBP-1 levels observed in vivo and provide an in vitro model for studies of IGFBP-1 biosynthesis.

Isolated growth hormone deficiency (IGHD) represents conditions of GH deficiency that are not necessarily associated with other pituitary hormone deficiencies or with an organic lesion. Three sub-categories of IGHD have been clinically identified (IGHD types 1–3), and IGHD type 1 has been further separated into IGHD types 1a and b. However, this clinical sub-categorization of IGHD may need reconsideration due to the recent identification of molecular heterogeneity within each sub-type of IGHD. In a small number of children with IGHD, defects in the GH, GH-releasing hormone receptor (GHRH-R), and GH1 genes have been identified. In most cases, no cause for IGHD can be identified; however, the proportion of idiopathic IGHD cases may be decreasing due to identification of causative factors. The phenotype of IGHD is variable depending in part on the underlying genetic disorders in the affected individuals. Several studies have focused on the usefulness of MRI findings in patients with GHD but anatomic abnormalities of the pituitary gland are variable. We review current studies and the clinical, biochemical, and molecular features described for different groups of affected individuals with IGHD.

Pediatric pituitary diagnosis is complicated by the unique developmental characteristics, secretory patterns and regulation of each pituitary hormone system. Although dynamic test procedures have been described, validation of each procedure is limited and universally agreed diagnostic criteria are not available. Clinical acumen, experience and judgment continue to be primary elements of pituitary diagnosis.

Objective The mouse serves as an important model for insulin-like (IGF)-related research. However, lack of homologous mouse assays has prevented studies of the normal ontology of the murine IGF system. Therefore, we developed and validated immunoaassays for murine IGF-I, IGFBP-3 and ALS and studied levels of these analytes in mice. Methods Using commercially available reagents, we developed and validated specific enzyme-linked immunosorbent assays (ELISAs) for murine IGF-I, IGFBP-3, and ALS. Levels of these analytes were measured in sera from CD-1 mice, male and female, sampled at 1, 2, 4, 8, 20 and 32 weeks of age. In addition, sera from pregnant and postpartum CD-1 mice were also studied. Results Validation of specific ELISAs for murine IGF-I, IGFBP-3 and ALS are described; all 3 assays were highly sensitive, precise and accurate. As measured by our homologous ELISA, IGF-I levels (ng/mL, mean ± SD) in male mice were relatively low at 1 week (53 ± 8), rising sharply to peak at 8 weeks of age (636 ± 48), and gradually declining thereafter, reaching 395 ± 64 at 32 weeks. IGF-I levels in non-pregnant female mice peaked at 4 weeks of age (548 ± 77) declined at 8 weeks (417 ± 61), then recovered to plateau at 539 ± 78 and 535 ± 88 at 20 and 32 weeks, respectively. In male mice, trends in IGFBP-3 were similar to the patterns of IGF-I. However, in non-pregnant female mice, the IGFBP-3 levels declined relatively slowly after peaking at 4-weeks of age, unlike IGF-I levels during this period. ALS levels followed the same pattern as IGF-I in both sexes. IGF-I to IGFBP-3 molar ratios (percent) were similar between sexes, rising continuously with age: ∼30% at 1 week, 80% at 4 weeks, 135% at 32 weeks. IGF-I was reduced in 8 week old mice in mid-pregnancy (354 ± 75 vs 417 ± 61 in non-pregnant 8 week females), reaching a nadir in late-term (146 ± 40), and only partially recovering in the postpartum period (239 ± 23). IGFBP-3 was also lower in late-pregnancy (1245 ± 100 vs 1925 ± 439) and remained depressed postpartum. In contrast to IGF-I and IGFBP-3, ALS increased more than threefold in mid-pregnancy (12180 ± 1641 vs 3741 ± 910), followed by a 4-fold decrease in late-pregnancy (2964 ± 489), recovering postpartum (6104 ± 1178). Conclusions We report the first ontological studies of IGF-I, IGFBP-3 and ALS in mice using newly-characterized sensitive, homologous immunoassays. Our results indicate that mice have a generally similar pattern in IGF-related axis components, with low levels early in life, increasing to peak during sexual maturation and declining thereafter. Significant gender differences in non-pregnant levels and dramatic changes during pregnancy were also found. Knowledge of the normal developmental changes in the murine IGF system and accurate tools for investigations of this system are a necessary foundation for research in this field.