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Purpose: To evaluate the utility of Insulin-like growth factor I (IGF-I) standard deviation score (SDS) as a surrogate marker of severity of hypopituitarism in adults with pituitary pathology., Methods: We performed a retrospective data analysis, including 269 consecutive patients with pituitary disease attending a tertiary endocrine clinic in 1990-2015. The medical files were reviewed for the complete pituitary hormone profile, including IGF-I, and clinical data. Age-adjusted assay reference ranges of IGF-I were used to calculate IGF-I SDS for each patient. The main outcome measures were positive and negative predictive values of low and high IGF-I SDS, respectively, for the various pituitary hormone deficiencies., Results: IGF-I SDS correlated negatively with the number of altered pituitary axes (p < 0.001). Gonadotropin was affected in 76.6 % of cases, followed by thyrotropin (58.4 %), corticotropin (49.1 %), and prolactin (22.7 %). Positive and negative predictive values yielded a clear trend for the probability of low/high IGF-I SDS for all affected pituitary axes. Rates of diabetes insipidus correlated with IGF-I SDS values both for the full study population, and specifically for patients with non-functioning pituitary adenomas., Conclusions: IGF-I SDS can be used to evaluate the somatotroph function, as a valid substitute to absolute IGF-I levels. Moreover, IGF-I SDS predicted the extent of hypopituitarism in adults with pituitary disease, and thus can serve as a marker of hypopituitarism severity.

Context: Data on pituitary imaging in adult male patients presenting with hypogonadotrophic hypogonadism (HH) and no known pituitary disease are scarce., Objective: To assess the usefulness of pituitary imaging in the evaluation of men presenting with HH after excluding known pituitary disorders and hyperprolactinemia., Design: A historical prospective cohort of males with HH., Patients: Men who presented for endocrine evaluation from 2011 to 2014 with testosterone levels <10.4 nmol/L (300 ng/mL), normal LH and FSH levels and no known pituitary disease., Results: Seventy-five men were included in the analysis. Their mean age and BMI were 53.4 ± 14.8 years and 30.7 ± 5.2 kg/m2, respectively. Mean total testosterone, LH, and FSH were 6.2 ± 1.7 nmol/L, 3.4 ± 2 and 4.7 ± 3.1 mIU/L, respectively. Prolactin level within the normal range was obtained in all men (mean 161 ± 61, range 41-347 mIU/L). Sixty-two men had pituitary MRI and 13 performed CT. In 61 (81.3%) men pituitary imaging was normal. Microadenoma was found in 8 (10.7%), empty sella and thickened pituitary stalk in one patient (1.3%) each. In other four patients (5.3%) a small or mildly asymmetric pituitary gland was noted. No correlation was found between testosterone level and the presence of pituitary anomalies., Conclusions: This study suggests that the use of routine hypothalamic-pituitary imaging in the evaluation of IHH, in the absence of clinical characteristics of other hormonal loss or sellar compression symptoms, will not increase the diagnostic yield of sellar structural abnormalities over that reported in the general population.

Objective: Nonfunctioning pituitary adenomas (NFPAs) are the most common type of pituitary adenomas diagnosed in older patients. However, there are insufficient data regarding the clinical course, risk of regrowth, and long-term prognosis in elderly versus younger patients., Methods: This retrospective cohort study observed 105 adult patients with NFPAs diagnosed between 1995 and 2012. Patients were stratified into 3 age groups: 18 to 44 years (29 patients), 45 to 64 years (38 patients), and 65 years and over (38 patients). The impact of age on presenting symptoms, disease course, and outcome was analyzed., Results: Adenoma size was larger in patients <45 years (mean, 2.9 ± 1.2 cm) compared to patients aged 45 to 64 years and those ≥65 years old (2.3 ± 0.9 and 2.5 ± 0.8 cm, respectively; P = .05), with transsphenoidal surgery being the treatment of choice in all 3 groups (83, 92, and 84%, not significant). After a mean follow-up of 6 years, there were higher recovery rates from hypopituitarism in patients <45 years old (58% vs. 27% and 24%; P = .04). Visual fields improved in most affected patients in each group following surgery (74, 94, and 86%), with a trend toward more full normalization in the youngest age group (58% vs. 44% and 41%; P = .09). There were no significant differences in the risk of remnant growth (29 to 39%), rates of radiation therapy, or need for repeated surgeries. There was no disease-related mortality., Conclusion: Elderly patients with NFPA have lower rates of recovery from hypopituitarism after treatment compared to younger patients, but the rates of regrowth and need for salvage surgery are similar.

Although pituitary adenomas are usually benign, unique trophic mechanisms restraining cell proliferation are unclear. As GH-secreting adenomas are associated with p53/p21-dependent senescence, we tested mechanisms constraining non-functioning pituitary adenoma growth. Thirty six gonadotroph-derived non-functioning pituitary adenomas all exhibited DNA damage, but undetectable p21 expression. However, these adenomas all expressed p16, and >90% abundantly expressed cytoplasmic clusterin associated with induction of the Cdk inhibitor p15 in 70% of gonadotroph and in 26% of somatotroph lineage adenomas (p  =  0.006). Murine LβT2 and αT3 gonadotroph pituitary cells, and αGSU.PTTG transgenic mice with targeted gonadotroph cell adenomas also abundantly expressed clusterin and exhibited features of oncogene-induced senescence as evidenced by C/EBPβ and C/EBPδ induction. In turn, C/EBPs activated the clusterin promoter ∼5 fold, and elevated clusterin subsequently elicited p15 and p16 expression, acting to arrest murine gonadotroph cell proliferation. In contrast, specific clusterin suppression by RNAis enhanced gonadotroph proliferation. FOXL2, a tissue-specific gonadotroph lineage factor, also induced the clusterin promoter ∼3 fold in αT3 pituitary cells. As nine of 12 pituitary carcinomas were devoid of clusterin expression, this protein may limit proliferation of benign adenomatous pituitary cells. These results point to lineage-specific pathways restricting uncontrolled murine and human pituitary gonadotroph adenoma cell growth.