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The apparent retroconversion of docosahexaenoic acid (22:6n-3) to eicosapentaenoic acid (20:5n-3) and docosapentaenoic acid (22:5n-3) was studied in vivo, in rats and humans, after they ingested a single dose of triacylglycerols containing [13C]22:6n-3 ([13C]22:6-triacylglycerol), without 22:6n-3 dietary supplementation. The amount of apparent retroconversion and the distribution of the three n-3 polyunsaturated fatty acids (PUFAs) in plasma lipid classes were followed as a function of time by measuring the appearance of 13C in these PUFAs with gas-chromatography combustion-isotope ratio mass spectrometry. This [13C]22:6n-3 retroconversion, calculated by summing the amounts of [13C]22:5n-3 and [13C]20:5n-3 in plasma lipids, was lower in humans than in rats, reaching a maximum of approximately 9% of the total plasma [13C]22:6n-3 in rats, but only 1.4% in humans. The incorporation of [13C]22:6n-3 and [13C]22:5n-3 in lipid classes followed their endogenous distribution with a maximal accumulation in phospholipids, but a low incorporation into cholesterol esters (CEs), whereas [13C]20:5n-3 was equally present in phospholipids and CEs. The ratio of the amount of HDL-CE to HDL-phosphatidylcholine for [13C]20:5n-3 was higher than for [13C]22:6n-3, indicating a selectivity of the lecithin-cholesterol acyltransferase enzyme with regard to these PUFAs, which may be related to the differences in their biological properties after fish oil feeding. The occurrence of a weak basal 22:6n-3 retroconversion in humans supports feeding this pure PUFA in cases in which 20:5n-3 presents undesirable side effects and when specific alterations of blood lipids are expected.

The aim of the present study was to compare the metabolic fate of repeated doses of fructose or glucose ingested every 30 min during long-duration moderate-intensity exercise in men. Healthy volunteers exercised for 3 h on a treadmill at 45% of their maximal oxygen consumption rate. "Naturally labeled" [13C]glucose or [13C]fructose was given orally at 25-g doses every 30 min (total feeding: 150 g; n = 6 in each group). Substrate utilization was evaluated by indirect calorimetry, and exogenous sugar oxidation was measured by isotope ratio mass spectrometry on expired CO2. Results were corrected for baseline drift in 13C/12C ratio in expired air due to exercise alone. Fructose conversion to plasma glucose was measured combining gas chromatography and isotope ratio mass spectrometry. Most of the ingested glucose was oxidized: 81 +/- 4 vs. 57 +/- 2 g/3 h for fructose (2P < 0.005). Exogenous glucose covered 20.8 +/- 1.4% of the total energy need (+/- 6.7 MJ) compared with 14.0 +/- 0.6% for fructose (2P < 0.005). The contribution of total carbohydrates was significantly higher and that of lipids significantly lower with glucose than with fructose. The blood glucose response was similar in both protocols. From 90 to 180 min, 55–60% of circulating glucose was derived from ingested fructose. In conclusion, when ingested repeatedly during moderate-intensity prolonged exercise, fructose is metabolically less available than glucose, despite a high rate of conversion to circulating glucose.

Defective regulation of gene expression may be involved in the pathogenesis of type 2 diabetes. We have characterized the concerted regulation by insulin (3-h hyperinsulinemic clamp) of the expression of 10 genes related to insulin action in skeletal muscle and in subcutaneous adipose tissue, and we have verified whether a defective regulation of some of them could be specifically encountered in tissues of type 2 diabetic patients. Basal mRNA levels (determined by reverse transcriptase-competitive polymerase chain reaction) of insulin receptor, insulin receptor substrate-1, p85alpha phosphatidylinositol 3-kinase (PI3K), p110alphaPI3K, p110betaPI3K, GLUT4, glycogen synthase, and sterol regulatory-element-binding protein-1c (SREBP-1c) were similar in muscle of control (n = 17), type 2 diabetic (n = 9), type 1 diabetic (n = 9), and nondiabetic obese (n = 9) subjects. In muscle, the expression of hexokinase II was decreased in type 2 diabetic patients (P0.01). In adipose tissue, SREBP-1c (P0.01) mRNA expression was reduced in obese (nondiabetic and type 2 diabetic) subjects and was negatively correlated with the BMI of the subjects (r = -0.63, P = 0.02). Insulin (+/-1,000 pmol/l) induced a two- to threefold increase (P0.05) in hexokinase II, p85alphaPI3K, and SREBP-1c mRNA levels in muscle and in adipose tissue in control subjects, in insulin-resistant nondiabetic obese patients, and in hyperglycemic type 1 diabetic subjects. Upregulation of these genes was completely blunted in type 2 diabetic patients. This study thus provides evidence for a specific defect in the regulation of a group of important genes in response to insulin in peripheral tissues of type 2 diabetic patients.

An association with subcutaneous adipose tissue TNFalpha expression and insulin resistance has been suggested in obesity/type-2 diabetes, but this has not been examined directly. In the first part of the study we investigated whether this association is present in 7 lean, 10 obese nondiabetic and 9 type-2 diabetic men. In the second part of the study we examined the relationship between adipose tissue TNFalpha mRNA levels and BMI in 81 nondiabetic subjects spanning a wide range of BMIs.Subcutaneous adipose tissue TNFalpha mRNA levels and insulin sensitivity were determined with quantitative RT-competitive PCR and hyperinsulinaemic clamp, respectively.Subcutaneous adipose tissue TNFalpha mRNA levels were similar in 7 lean and 10 obese nondiabetic and 9 type-2 diabetic men (P = 0.68), and did not change in response to 240-min hyperinsulinaemia. TNFalpha mRNA levels and insulin sensitivity were not correlated. Unexpectedly, no correlation between TNFalpha mRNA and BMI was found. The relationship between adipose tissue TNFalpha mRNA and BMI was examined further in 31 male and 50 female nondiabetic subjects. The subcutaneous adipose tissue TNFalpha mRNA level correlated with BMI in all subjects (rS = 0.32, P0.01), and in a subgroup analysis in men (rS = 0.55, P0.01) but not in women (rS = - 0.08). The correlation in men was dependent on a fourfold higher TNFalpha mRNA level in 5 morbidly obese men while there was no difference in TNFalpha mRNA levels in lean or obese men.Subcutaneous adipose tissue TNFalpha expression does not correlate with insulin sensitivity in nondiabetic or type-2 diabetic men; is not regulated by acute hyperinsulinaemia; and is increased only in morbidly obese men.

To assess the effects of angiotensin converting enzyme (ACE) inhibitor on insulin action in obesity, five normotensive non-diabetic obese women were examined on two occasions as part of a double-blind, randomized, cross-over study involving ten days of treatment with either 1.25 mg ramipril or placebo. The study consisted of a euglycaemic hyperinsulinaemic clamp (two periods of insulin infusion at rates of 0.4 and 1 mU/kg/min, 2 h for each step) combined with indirect calorimetry. The most notable results involved a significantly faster time-course of glucose infusion rates during the first 30 min of each insulin infusion period [analysed by calculating slopes (S1 and S2)] after ramipril than placebo administration. The mean glucose infusion rates reached during the last 30 min of each insulin infusion period (G1 and G2), as well as the increases in carbohydrate oxidation rates during the clamp (C1-C0 and C2-C0) and the decreases in plasma nonesterified fatty acids (A0-A1 and A0-A2), were not significantly different after ramipril and placebo. According to robust principal component analysis of S1, S2, G1, G2, C1, C2, A1 and A2 (orthogonally to C0 and A0), insulin sensitivity was improved with ramipril as compared to placebo (p = 0.013). This study strongly suggests that a low dose of an ACE inhibitor increases the activation phase of insulin action in normotensive nondiabetic obese patients and may accelerate insulin action.

Morbid obesity, defined by Body Mass Index (BMI)40 kg/m2, has an adverse effect on longevity due to a variety of illnesses. Among the numerous techniques proposed to control morbid obesity, Vertical Banded Gastroplasty (VBG) changes eating behavior. The aim of this study was to analyse the long term results of VBG.Between October 1987 and July 1993, 62 patients, 7 men and 55 women, from 20 to 68 years old (Mean: 37.4 +/- 9 ans), underwent VBG for morbid obesity. Preoperative mean weight and BMI were 123 +/- 27 kg and 47.3 +/- 9.8 kg/m2 respectively. Associated diseases were diabetes mellitus (n = 31), hypertension (N = 29), hypercholesterolemia (N = 10), hypertriglyceridemia (N = 21) and joint diseases (N = 18).VBG was performed with a 50 mm marlex mesh in 20 cases and with a 47 to 50 mm silastic ring in 42 cases. On patient died 3 years later from alcoholic liver cirrhosis and 4 were lost to follow-up. With a mean follow-up of 31 months, mean weight and BMI were 86 +/- 21 kg (p0.001) and 32.1 +/- 9.8 kg/m2 (p0.001) respectively. Removal of the ring was performed in 3 cases, 1 because of neurologic complications and 2 at the patient's request. Eight patients (13%) failed to achieve satisfactory weight loss. Diabetes mellitus and hypertension resolved in 19 cases, hypercholesterolemia resolved in 7 cases and hypertriglyceridemia resolved in 11.VBG provides significant weight loss which reduces the frequency of medical disorders associated with obesity. This result was achieved in 87% of patients. The surgical procedure for morbid obesity must be decided conjointly with endocrinologist, psychiatrist and surgical staff for good long-term results.

Multiple Endocrine Neoplasia type 1 (MEN 1) is an autosomal dominant familial syndrome characterized by involvement of several endocrine glands, including parathyroid, pancreatic islet cells, anterior pituitary and diffuse neuroendocrine tissues (carcinoids). The gene causing this syndrome has been localized to chromosome 11 but was not cloned up-to-date. Pre-clinical diagnosis in predisposed MEN 1 families was based on the use of genetic linkage analysis with polymorphic DNA probes flanking the disease locus. The set-up collaborative multi-disciplinar medical and surgical network facilitates further clinical and genetic studies on MEN 1 families. Semiological course of the disease is complex and the main objective in clinical follow-up of patients and related is to limit the probability of misdiagnosis. The present report describe the clinical and genetic analysis in a MEN 1 family and the difficulties related to diagnose the disease. An interesting observation on two cases of hyperprolactinemia by two individuals further excluded by genetic analysis assess the potential risk of bias in genetic linkage studies in non-well documented families. Concerted analysis of genetic and bio-clinical data permitted the evaluation of each patient and to exclude the risk of MEN 1 in all children tested. This example demonstrates the need of a complete clinical information previously to genetic analysis and a multi-disciplinar and collaborative approach in follow-up of patients in each family.

We report the renal and metabolic effects of a 40 day administration of recombinant human growth hormone in a 31 years old diabetic and GH-deficient patient who underwent a kidney and pancreas transplantation. The data show an increase in glomerular filtration rate, tubular reabsorption of phosphate, and plasma hemoglobin level. Anabolism is suggested from a decrease in serum urea nitrogen and an increase in muscle mass (increase in plasma creatinine). These positive effects might be partly explained by an overcome of endogenous growth hormone resistance when administering pharmacological doses of recombinant growth hormone.

Background and Objective: Reports of multiple primary tumors are not new. However, we have noted a disproportionate number of patients with melanoma in whom lymphoma develops and wanted to define the incidence of this association. Design: All 664 patients with melanoma treated at Yale-New Haven Hospital, Conn, during the 5-year period from 1986 to 1991 were reviewed. The incidence of all the associated malignant neoplasms among our patients with melanoma was compared with the incidence that would be expected in the normal population adjusted for age, race, and sex. Results: Among the 664 patients, 54 (8.1%) had one or more additional malignant neoplasms. Of the 10 different malignant tumor types recorded, lymphomas were the most prevalent. This incidence of lymphoma among the melanoma patients was 12 of 664, resulting in an incidence of 548 per 100 000 population, 16 times higher ( P Conclusions: The incidence of a second malignant neoplasm in our patients with melanoma was 8.1%. Lymphoma was a particularly common type of second malignancy, showing an incidence more than 16-fold higher than that expected in the normal population. It is particularly important, from a clinical point of view, to be aware of this when clinically palpable lymph nodes develop in areas not normally the site of regional lymphatic drainage of the primary melanoma. (Arch Surg. 1995;130:1056-1061)

Using gas chromatography-isotope ratio mass spectrometry, the detection, with a good reproducibility and in a single step, of the 13C content of glycoprotein neutral sugars, glycogen glucose, and ribonucleic acid ribose allowed us to trace incorporation into intestinal macromolecules of sugars derived from dietary glucose, labeled either naturally (as corn starch) or artificially. The 13C enrichment of glycoprotein neutral sugars was strong and rapid and plateaued up to the end of the experiment, whereas the 13C content of ribose increased linearly with time. By contrast, with artificially enriched dietary glucose, no significant 13C enrichment was detected in glycogen, suggesting that this macromolecule does not directly derive from dietary glucose. These results suggest differential control of sugars involved in the synthesis of intestinal macromolecules and demonstrate that this technique would be sensitive and reliable enough to be applied in man for serum glycoprotein sugar determinations.

Glucose-6-phosphatase (Glc6Pase) is a liver microsomal protein exhibiting a high specificity for glucose-6-phosphate (Glc6P) when present in the intact membrane. On the contrary, Glc6Pase of detergent-treated liver microsomes is able to hydrolyze both Glc6P and mannose-6-phosphate (Man6P) with the same affinities and rates (Km and Vmax) at pH 6.5 [Ajzannay, A., Minassian, C., Riou, J.P., and Mithieux, G. (1993) Eur. J. Biochem. 212, 335-338]. We have carried out competition experiments between constant micromolar concentrations of [U-14C]Glc6P and [U-14C]Man6P and increasing millimolar concentrations of unlabeled Glc6P and Man6P. The rate of hydrolysis of [U-14C]Glc6P was progressively inhibited as the competitor concentration increased, but it was significantly higher in the presence of Man6P than in the presence of Glc6P (twofold higher at 20 mM). In the same manner, the rate of hydrolysis of [U-14C]Man6P was inhibited by increasing concentrations of competitor, but it was significantly higher when the competitor was Man6P than when the competitor was Glc6P. These data provide direct evidence that, in the presence of both Glc6P and Man6P, Glc6Pase is able to exhibit a specific, albeit limited, kinetic behavior towards the former after detergent treatment of the membrane. They also emphasize the role of the membrane in the acquisition of the final specificity of Glc6Pase under physiological conditions.

We have used a new enzyme-linked immunoassay (ELISA) to measure the urinary excretion of type I collagen peptides (CrossLaps) released during bone matrix degradation in a sample of healthy adults comprising 146 women and 60 men, aged 31-89 yr, and in patients with metabolic bone disease. The intra- and interassay coefficients of variation were less than 10% and 13%, respectively. The recovery of CrossLaps antigen from urine samples ranged from 92-115%, and the ELISA was linear for serial sample dilutions. The CrossLaps assay does not cross-react with either free pyridinoline (Pyr) or free deoxypyridinoline (D-Pyr). CrossLaps measured by ELISA and the total excretion of Pyr measured by high performance liquid chromatography were highly correlated in normal women (n = 91; r = 0.73; P0.001). Urinary CrossLaps excretion increased with age in women, but not in men. In women, the menopause was reflected by a mean 141% increase in CrossLaps excretion [from an average 217 to 524 micrograms/mmol creatinine (Cr)] that was higher than the mean increase in total D-Pyr (+91%) and total Pyr (+47%) measured by HPLC and the mean increase in bone alkaline phophatase (+48%) and osteocalcin (+41%). Urinary CrossLaps excretion was increased from control values in Paget's disease (n = 32; mean, 1810 +/- 2300 micrograms/mmol Cr; P0.001), in patients with primary hyperparathyroidism (n = 10; mean, 780 +/- 380 micrograms/mmol Cr; P0.001), and in patients with hyperthyroidism (n = 27; mean, 1280 +/- 970 micrograms/mmol Cr; P0.001), with Z-scores (number of SD from the mean of sex- and age-matched controls) of 4.4 +/- 6.6, 1.5 +/- 1.2, and 6.7 +/- 6.5, respectively. In patients with Paget's disease, CrossLaps values were highly correlated with urinary hydroxyproline levels (r = 0.91; P0.001), and the decrease in urinary CrossLaps excretion was greater than that in urinary hydroxyproline (-71% vs. -17%; P0.001) after 3 days of i.v. treatment with the bisphosphonate pamidronate. In patients with hyperthyroidism, CrossLaps excretion was elevated above the normal range in most patients (78%) and returned to normal within 1 month of treatment for hyperthyroidism. It is concluded that this new convenient assay represents a sensitive and specific index of the bone resorption rate, and that it should be useful for the clinical investigation and therapeutic monitoring of patients with osteoporosis and other metabolic bone diseases.

Detection of subjects from a multiple endocrine neoplasia type 1 family must rest on clinical, biochemical and radiological data, since study of the genome is unable to detect these subjects. In the new family described here, 6 out of the 14 subjects explored were affected. One had a confirmed pancreatic endocrine tumour and in 3 others a pancreatic endocrine tumour was highly probable, since insulin and glucagon levels, as well as ultrasonic exploration of the pancreas were pathological. Measurements of gastrointestinal hormones gave normal results in all cases. We conclude that to detect this endocrine neoplasia in subjects at risk it seems necessary to measure plasma insulin levels and perform an abdominal ultrasonography.

Accurate determination of energy requirement and nutrients metabolism is essential to improve physiological knowledge and for physiopathological purpose in human nutrition. This evaluation is an absolute necessity for food industry. Energy expenditure could be precisely determined by indirect calorimetry or doubly labeled water technic. Nutrients metabolism and substrates turn-over studies are now accessible without health hazard using tracers labelled with stable isotopes. These three methods are the basic tools for the new Research Nutrition Center which are now in progress.

Accurate determination of energy requirement and nutrients metabolism is essential to improve physiological knowledge and for physiopathological purpose in human nutrition. This evaluation is an absolute necessity for food industry. Energy expenditure could be precisely determined by indirect calorimetry or doubly labeled water technic. Nutrients metabolism (kinetics?) and substrates turn-over studies are now accessible without health hazard using tracers labelled with stable isotopes. These three methods are the basic tools for the new Research Nutrition Center which are now in progress.

We have recently shown that the Ca.EGTA and Mg.EDTA complexes, but not free Ca2+ or Mg2+, inhibit the liver glucose-6-phosphatase (Mithieux, G., Vega, F. V., Beylot, M., and Riou, J. P. (1990) J. Biol. Chem. 265, 7257-7259). In this work, we report that, when complexed with Mg2+, two endogenous dicarboxylic keto acids (alpha-ketoglutarate (alpha-KG) and oxaloacetate (OAA] inhibit the glucose-6-phosphatase activity at low concentrations of substrate. This phenomenon is specific for complexes of Mg2+ with alpha-KG and OAA since 1) the complexes of Mg2+ with a number of other di- or tricarboxylic acids having high structural analogy with alpha-KG and OAA (oxalate, malate, succinate, citrate, aspartate, and glutamate) do not inhibit the glucose-6-phosphatase activity and 2) the Ca.alpha-KG and Ca.OAA chelates do not inhibit the glucose-6-phosphatase activity. In the presence of Mg.alpha-KG or Mg.OAA chelates, the enzyme displays sigmoid kinetics; the Hanes plots deviate from linearity, indicating the positive cooperative dependence of the velocity upon the substrate concentration. Hill coefficients (equal to 1 in the absence of the chelates) of 1.23 and 1.33 have been determined in the presence of Mg.alpha-KG and Mg.OAA complexes, respectively. The disruption of microsomal integrity by detergents abolishes the effect of Mg.alpha-KG and Mg.OAA, suggesting that the magnesium chelates inhibit the translocase component of the glucose-6-phosphatase system.

It has recently been reported that free Ca2+, a second hormonal messenger in the liver, can modulate the activity of liver glucose-6-phosphatase by inhibition (van de Werve, G. (1989) J. Biol. Chem. 264, 6033-6036) or activation (Yamagushi, M., Mori, S., and Suketa, Y. (1989) Chem. Pharm. Bull. (Tokyo) 37, 388-390). Such a controversial role for Ca2+ is reinvestigated by comparing the effect of the addition of free Ca2+ (10(-10) to 20.10(-3) M) under the form of CaCl2 or of Ca-EGTA buffers. We show that the glucose-6-phosphatase activity is: 1) increased in the presence of CaCl2 at concentrations higher than 10(-4) M and unaffected in the presence of CaCl2 at lower concentrations; 2) decreased in the presence of Ca-EGTA buffers yielding free Ca2+ concentrations higher than 10(-8) M; 3) the latter effect is not depending on free Ca2+ or free EGTA concentrations, but on Ca.EGTA complex concentration. In addition, these effects can be reproduced in the same concentration ranges by MgCl2 and Mg-EDTA buffers, respectively. It is concluded that a physiological role for free Ca2+ on the activity of liver glucose-6-phosphatase remains to be established.

In order to determine if intraperitoneal insulin infusion could improve the insulin resistance of type 1 diabetic patients we have used the englycaemic insulin clamp technique in order to study the effects of insulin on glucose disposal in four C peptide negative type 1 diabetic patients treated by continuous subcutaneous or intraperitoneal insulin infusion and in five control subjects. Compared to control subjects, the diabetic patients treated by subcutaneous insulin infusion had a decreased maximal capacity of glucose utilization (diabetics: 12.6 +/- 0.3 mg.kg-1.min-1; controls: 15.7 +/- 0.7 mg/kg-1.min-1, p less than 0.01) and a trend towards higher half-maximally effective insulin concentrations (diabetics: 70 +/- 11 mU/l-1, controls: 48 +/- 4 mU/l-1). Treatment of the diabetic patients by intraperitoneal insulin infusion for 2 months decreased their mean peripheral free insulin levels (during subcutaneous infusion: 23.5 +/- 2.2 mU/l-1; during intraperitoneal infusion: 18.4 +/- 1.4 mU/l-1, p less than 0.05). However, mean daily insulin requirements were not decreased (during subcutaneous infusion: 0.59 +/- 0.05 U/kg-1.day-1; during intraperitoneal infusion: 0.57 +/- 0.03 U/kg-1.min-1). Moreover, the diabetic patients had a consistently lower maximal capacity of glucose utilization (12.6 +/- 0.7 mg kg-1.min-1) than control subjects (p less than 0.01) without modification of the half-maximally effective insulin concentration (62 +/- 10 mU.l-1). In conclusion, the only benefit of intraperitoneal insulin infusion was a reduction of peripheral free insulin levels; this decrease of peripheral insulinaemia was not associated with an improvement in the insulin resistance of diabetic patients.

Hydroxyproline excretion was increased by hyperthyroid patients. This increase was related to thyroid hormone levels. Propranolol administration induced a decrease in hydroxyproline excretion and in immunoreactive triiodothyronine. Indometacin administration induced a decrease in urinary excretion of prostaglandins but had no effect on hydroxyproline excretion. These data suggest that the increased bone resorption of hyperthyroidism may involve a catecholamine beta receptor-dependent mechanism and is probably independent of prostaglandins.

Rat hepatic pyruvate kinase (type L) has been purified to homogeneity by a simple, rapid procedure involving DEAE-cellulose chromatography and elution from a blue Sepharose column. The enzyme was homogeneous by the criteria of sodium dodecyl sulfate disc gel electrophoresis, had a subunit molecular weight of 57,000, and a specific activity of 558 units/mg of protein at 30 degrees. In order to test whether the enzyme is phosphorylated in vivo, rats were injected with radioactive inorganic phosphate. Incorporation into pyruvate kinase was determined after purification of the enzyme to homogeneity as well as after specific immunoprecipitation of the enzyme from partially purified preparations. Sodium dodecyl sulfate disc gel electrophoresis revealed that 32P was incorporated into the enzyme in both cases. Glucagon administration in vivo resulted in a 200 to 300% increase in the incorporation of 32P into the enzyme which was correlated with an inhibition of enzyme activity and an elevation of hepatic levels of cyclic AMP. These results represent the first demonstration of in vivo phosphorylation of a hepatic glycolytic enzyme and strongly support the hypothesis that glucagon regulates pyruvate kinase activity, at least in part, by a phosphorylation mechanism.

In order to evaluate the role of beta-receptor mediated effects of catecholamines in the metabolic deterioration following insulin withdrawal in insulin-dependent diabetic patients we have measured in 5 patients metabolic substrate and hormone concentrations during a 6 hours arrest of insulin infusion, without or with a simultaneous infusion of propranolol. During insulin deprivation plasma epinephrine and norepinephrine increased slightly (from 107 +/- 10 ng/L to 173 +/- 6 ng/L and from 307 +/- 37 ng/L to 518 +/- 77/ng/L respectively (p less than 0.05), cortisol decreased physiologically, but growth hormone and glucagon were not significantly modified. Free insulin decreased progressively from 12.2 +/- 2.5 mU/L to 5.4 +/- 1.1 mU/L (p less than 0.01). Blood glucose and ketone bodies rose sharply before any significant change in catecholamine levels. Plasma free fatty acids and blood glycerol increased progressively and their rise appeared somewhat temporally related to the variations of catecholamine levels. The addition of propranolol to insulin deprivation did not modify the changes in hormone concentrations in spite of a slightly greater rise of epinephrine (from 78 +/- 4 ng/L to 179 +/- 7 ng/L, p less than 0.05) and norepinephrine (from 395 +/- 80 ng/L to 679 +/- 153 ng/L, p less than 0.05). The rises of glucose and ketone bodies were unaffected whereas the increases of free fatty acids and glycerol were slightly blunted. In conclusion, we have no evidence for a beta-adrenergic mediated role for catecholamines in the development of hyperglycaemia and ketonaemia in non-stressed insulin deprived diabetic patients, and only small evidence for a permissive effect on lipolysis.

Lean body mass and muscle protein breakdown were evaluated in euthyroid and hyperthyroid subjects by measuring the urinary excretion of creatinine and 3-methylhistidine. Since catecholamines probably have an inhibitory effect on muscle protein catabolism through a beta-receptor mechanism, the effects of propranolol on 3-methylhistidine excretion were also evaluated in hyperthyroid subjects. Hyperthyroid subjects had a lower lean body mass (34.9 +/- 6.3 kg versus 47.7 +/- 8.9 kg, p less than 0.001) and a greater 3-methylhistidine excretion (25.1 +/- 7.4 versus 19.0 +/- 4.8 mumol/mmol creatinine, p less than 0.05) than euthyroid subjects. Propranolol administered orally to hyperthyroid subjects decreased pulse rate (p less than 0.01) and plasma triiodothyronine concentrations (from 5.40 +/- 2.28 to 3.61 +/- 1.61 nmol/l, p less than 0.01), but did not modify urinary 3-methylhistidine excretion (24.8 +/- 8.7 versus 25.1 +/- 7.4 mumol/mmol creatinine). These results suggest that muscle wasting in hyperthyroidism is related to increased protein catabolism. This increased protein breakdown is not modified by short term administration of propranolol, a beta-blocking agent widely used in the management of hyperthyroidism.

The hormonal control of [14C]glucose synthesis from [U-14C-A1dihydroxyacetone was studied in hepatocytes from fed and starved rats. In cells from fed rats, glucagon lowered the concentration of substrate giving half-half-maximal rates of incorporation while it had little or no effect on the maximal rate. Inhibitors of gluconeogenesis from pyruvate had no effect on the ability of the hormone to stimulate the synthesis of [14C]glucose from dihydroxyacetone. The concentrations of glucagon and epinephrine giving half-maximal stimulation from dihydroxacetone were 0.3 to 0.4 mM and 0.3 to 0.5 muM, respectively. The meaximal catecholamine stimulation was much less than the maximal stimulation by glucagon and was mediated largely by the alpha receptor. Insulin had no effect on the basal rate of [14C]clucose synthesis but inhibited the effect of submaximal concentration of glucagon or of any concentration of catecholamine. Glucagon had no effect on the uptake of dihydroxyacetone but suppressed its conversion to lactate and pyruvate. This suppression accounted for most of the increase in glucose synthesis. In cells from gasted rats, where lactate production is greatly reduced and the rate of glucose synthesis is elevated, glucagon did not stimulate gluconeogenesis from dihydroxyacetone. Findings with glycerol as substrate were similar to those with dihyroxyacetone. Ethanol also stimulated glucose production from dihydroxyacetone while reducing proportionately the production of lactate. Ethanol is known to generate reducing equivalents fro clyceraldehyde-3-phosphate dehydrogenase and presumably thereby inhibits carbon flux to lactate at this site. Its effect was additive with that of glucagon. Estimates of the steady state levels of intermediary metabolites and flux rates suggested that glucagon activated conversion of fructose diphosphate to fructose 6-phosphate and suppressed conversion of phosphoenolpyruvate to pyruvate. More direct evidence for an inhibition of pyruvate kinase was the observation that brief exposure of cells to glucagon caused up to 70% inhibition of the enzyme activity in homogenates of these cells. The inhibition was not seen when the enzyme was assayed with 20 muM fructose diphosphate. The effect of glucagon to lower fructose diphosphate levels in intact cells may promote the inhibition of pyruvate kinase. The inhibition of pyruvate kinase may reduce recycling in the pathway of gluconeogenesis from major physiological substrates and probably accounts fromsome but not all the stimulatory effect of glucagon.

We studied the effect of VIP on the ATPase activities from basolateral membranes prepared from rat enterocytes. Under the standard conditions of assay for membrane ATPases (millimolar ATP concentration) VIP has no effect, neither on the Na, K ATPase activity (ouabain sensitive) nor on the Mg ATPase activity (ouabain insensitive). These results suggest that short-term effects of VIP on ionic permeability and metabolism of enterocytes, are not mediated through modifications of the Na/K ratio by the Na, K ATPase or through modifications of another membrane ATPase activities.

We have determined peripheral venous somatostatin like immunoreactivity (SLI) levels in 11 normal subjects (blood glucose--BG--: 4.4 +/- 0.1 mM; ketone bodies--KB--: 90 +/- 12 microM; plasma free fatty acids--FFA --: 340 +/- 42 microM), 4 Biostator controlled insulin dependent diabetics (BG: 5.4 +/- 0.2 mM; FFA: 418 +/- 38 microM; KB: 226 +/- 41 microM) and 7 poorly controlled ketotic diabetics (BG: 10.8 +/- 1.3 mM; FFA: 915 +/- 19 microM; KB: 2490 +/- 576 microM). SLI was determined again after 48 to 96 hours of intravenous insulin infusion for the 7 ketotic diabetics and after transient interruption of insulin infusion for the Biostator controlled diabetics. Relative to normal subjects ketotic diabetics had elevated SLI levels (29.7 +/- 5.9 vs 13.5 +/- 1.8 ng/L, p less than 0.01) whereas biostator-controlled patient had near to normal values (20.4 +/- 6.4 ng/L, p greater than 0.30). Transient arrest of insulin infusion in the Biostator controlled diabetics resulted only in a mild metabolic deterioration (BG: 12.8 +/- 2.1 mM; FFA: 640 +/- 146 microM; KB: 950 +/- 163 microM) without a significant rise of SLI. Intravenous insulin infusion in the initially ketotic patients decreased BG and KB in each subject (p less than 0.01) but decreased FFA (1097 +/- 170 to 453 +/- 74 microM, p less than 0.05) and SLI (34.0 +/- 12.0 to 9.8 +/- 2.4 ng/L, p less than 0.05) only in 4 patients whereas both FFA (737 +/- 107 to 725 +/- 25 microM) and SLI (27.6 +/- 4.7 to 20.3 +/- 4.7 ng/L) levels remained stable in the other 3. These results suggest that SLI levels in type I diabetics are dependent the degree of metabolic control and could be related to the variations of FFA concentrations.

A 31 years old man with an adrenocortical carcinoma was studied. Clinically he had a bilateral and recidiving gynecomastia and showed high urinary oestrogens, 17 cetosteroids, tetra-hydro-desoxy-cortisol and pregnandiol excretion with normal cortisol production. A partial increase on ACTH, no suppression on dexamethasone and no variation on HCG administration were observed. The surgical resection of the tumor normalized this urinary excretion. The serum dehydro-epiandrosterone (DHEA) and sulfate (DHEAS), oestrone, oestradiol, androstenedione (A) levels were greatly elevated. No variations of the cortisol, A, DHEA and DHEAS was noted after ACTH injection. In vitro the lack of ACTH's action was related to an anomaly of ACTH receptor with normal protein kinase activity.

We have indirectly assessed the role of free fatty acids (FFA) and of hepatic ketogenesis in the regulation of ketone body levels in euthyroid and hyperthyroid subjects. All studies were performed under controlled dietary conditions (35 and 45 kcal/kg body weight/day respectively for euthyroid and hyperthyroid subjects). In the post-absorptive state hyperthyroid patients had normal, glucagon levels and, in spite of increased insulinemia (p less than 0.02), elevated concentrations of blood glucose (p less than 0.01), glycerol (p less than 0.001) and ketone bodies (p less than 0.05). In the face of this hyperketonaemia, there was no significant increase of plasma FFA, suggesting possible increased hepatic conversion of FFA to ketone bodies. However, when FFA were acutely raised to high levels, the induced rise of ketone bodies was similar in hyperthyroid and euthyroid subjects. Oral propranolol administration to hyperthyroid patients in the post-absorptive state decreased the concentrations of glycerol (p less than 0.05) and ketone bodies (p less than 0.05) without altering insulin concentrations. Ketone bodies fell without any significant decrease of FFA suggesting a possible direct effect of propranolol administration on hepatic ketogenesis. However, the ketone body response to raised FFA levels was unaffected by propranolol. We have evidence in hyperthyroid patients of increased lipolysis and ketogenesis in spite of increased daily caloric intake. These results suggest that these metabolic abnormalities are not merely due to relative starvation. We have tentative evidence for modification of the intra-hepatic conversion of FFA to ketone bodies in the post-absorptive state but no supporting evidence when FFA levels were experimentally raised.

In order to elucidate the mechanism of the Farquharson phenomenon, we studied the thyrotropin function in three groups of patients who had had high plasma levels of thyroid hormones for prolonged period of time : 3 patients (group A) had taken thyroid hormones for several years. One month after discontinuation of the treatment two of them were hypothyroid; in both of them plasma TSH did not increase after injection of TRH. Spontaneous recovery occured in those two patients respectively five and nineteen months after the end of the drug administration. One year after having stopped the treatment the third patient was apparently euthyroid; however, she was proved to have a complete TSH deficiency. Group B consisted of 27 patients who were studied after surgical ablation of toxic adenoma. Four of them were hypothyroid one to four months after surgery and had no response to TRH. Fifteen out of the 23 remaining patients were euthyroid but had such a lack of response to TRH from 5 days to one year after surgery. Group C consisted of forty three patients treated for Graves' disease and who had been euthyroid for at least one year following the treatment. Seven of them exhibited no or a subnormal response to TRH. Finally, thirteen patients (from groups A, B and C) who did not respond to TRH were given 10 mg TRH orally twice a day for two weeks. A normalization of the TRH test was then demonstrated in three patients and a partial recovery in three others. Thus, there is a frequent thyrotropin deficiency after prolonged high levels of plasma thyroid hormones which can disappear spontaneously or after chronic TRH administration.

Thyroid hormone effects have been studied in both rats and human. In rats ketone body levels are increased by thyroid hormone excess at the initial phase of starvation. Glucose levels are also increased at the initial and late phase of starvation. Ketone bodies production of isolated liver cells from thyroidectomized fed rats (14 +/- 0,2 muMol/g/h) are decreased when compared with cells from thyroidectomized fed rats treated with triiodothyronine 63 +/- 3 muMol/g/h). These changes are related to a direct effect of T3. Ketone bodies levels are increased in Grave's diseases. The increase is significantly correlated to thyroid hormone levels.

The hormonal and metabolic events occurring during an oral glucose load have been extensively characterised in man. The use of tracers, the splanchnic hepatic balance technique and indirect calorimetry [1] have permitted the measurement of most, if not all the kinetic parameters of glucose metabolism. Despite this extensive work the mechanisms involved in the regulation of glycaemia are still the subject of debate and research. Most of the sophisticated methodology used still needs to be applied to various carbohydrate nutrients which are usually transformed inside the body into glucose before being oxidised, stored or recycled. The aim of this short review is not to provide extensive data on the glycaemic index of various carbohydrates, but to focus on the respective roles of hormones and glucose per se, and to underline some remaining methodological problems in this kind of study.

Members of the peroxisome proliferator-activated receptor (PPAR) family might be involved in pathologies with altered lipid metabolism. They participate in the control of the expression of genes involved in lipid metabolism and adipocyte differentiation. In addition, thiazolidinediones improve insulin resistance in vivo by activating PPAR gamma. However, little is known regarding their tissue distribution and relative expression in humans. Using a quantitative and sensitive reverse transcription (RT)-competitive polymerase chain reaction (PCR) assay, we determined the distribution and relative mRNA expression of the four PPARs (alpha,beta, gamma1, and gamma2) and liver X receptor-alpha (LXR alpha) in the main tissues implicated in lipid metabolism. PPAR alpha and LXR alpha were mainly expressed in liver, while PPAR gamma1 predominated in adipose tissue and large intestine. We found that PPAR gamma2 mRNA was a minor isoform, even in adipose tissue, thus causing question of its role in humans. PPAR beta mRNA was present in all the tissues tested at low levels. In addition, PPAR gamma mRNA was barely detectable in skeletal muscle, suggesting that improvement of insulin resistance with thiazolidinediones may not result from a direct effect of these agents on PPAR gamma in muscle. Obesity and NIDDM were not associated with change in PPARs and LXR alpha expression in adipose tissue. The mRNA levels of PPAR gamma1, the predominant form in adipocytes, did not correlate with BMI, leptin mRNA levels, or fasting insulinemia in 29 subjects with various degrees of obesity. These results indicated that obesity is not associated with alteration in PPAR gene expression in abdominal subcutaneous adipose tissue in humans.