Monday, July 21, 2008

Prevalence of GH and other anterior pituitary hormone deficiencies in adults with nonsecreting pituitary microadenomas and normal serum IGF-1 levels

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Prevalence of GH and other anterior pituitary hormone deficiencies in adults with nonsecreting pituitary microadenomas and normal serum IGF-1 levels

Authors: Yuen, Kevin C. J.; Cook, David M.; Sahasranam, Prem; Patel, Pragnesh; Ghods, David E.; Shahinian, Hrayr K.; Friedman, Theodore C.

Source: Clinical Endocrinology, Volume 69, Number 2, August 2008 , pp. 292-298(7)

Publisher: Blackwell Publishing

Abstract:
Summary Objective

GH is usually the first pituitary hormone to be affected following a pathological insult to the pituitary; however, data on the prevalence of GH deficiency in patients with nonsecreting pituitary microadenomas and normal serum IGF-1 levels are scarce. This study aims to evaluate the prevalence of GH and other anterior pituitary hormone deficiencies, and to determine whether microadenomas per se could be associated with reduced GH response rates to GHRH-arginine stimulation.

Design

Analytical, retrospective, two-site case-control study.

Patients and methods

Thirty-eight patients with nonsecreting pituitary microadenomas (mean size 4·2 mm) and normal serum IGF-1 levels were studied. Anterior pituitary function testing, including the GHRH-arginine test to examine GH reserve, was performed in all patients. Serum IGF-1 levels and peak GH levels in the patients that passed the GHRH-arginine test were compared with 22 age- and BMI-matched healthy controls.

Results

Nineteen patients (50%) failed the GHRH-arginine test and had higher body mass index (BMI) than those that passed the GHRH-arginine test and healthy controls. Peak GH levels in patients that passed the GHRH-arginine test were lower compared to healthy controls and 19 patients (50%) had at least one other pituitary hormone deficit. A negative correlation (r = -0·42, P < 0·01) between peak GH levels and BMI was identified, but no correlations were found between peak GH and serum IGF-1 levels.

Conclusions

Our data demonstrated that a substantial number of patients with nonsecreting pituitary microadenomas failed the GHRH-arginine test despite normal serum IGF-1 levels, and had at least one other pituitary hormone deficiency, suggesting that nonsecreting microadenomas may not be clinically harmless. We therefore recommend long-term follow-up with periodic basal pituitary function testing, and to consider dynamic pituitary testing should clinical symptoms arise in these patients.

Document Type: Research article

DOI: 10.1111/j.1365-2265.2008.03201.x

Affiliations: 1: Department of Endocrinology, Oregon Health and Science University, Portland, OR 97239-3098, USA, 2: Division of Endocrinology, Metabolism and Molecular Medicine, The Charles Drew University of Medicine and Science, Los Angeles, CA 90059, USA and 3: Skull Base Institute, Los Angeles, CA 90048, USA

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