Physiological testosterone replenishment in healthy elderly men does not normalize pituitary growth hormone output: evidence against the connection between senile hypogonadism and somatopause

The Journal of Clinical Endocrinology and Metabolism
John J OrregoA L Barkan

Abstract

Normal aging in men is accompanied by lower serum testosterone (T), GH, and IGF-I concentrations. The mechanisms of the age-related diminution in the activity of the somatotropic axis (somatopause) are uncertain. Several explanations have been proposed, including a lower hypothalamic GHRH output. The aim of the present study was to test the hypothesis that the physiological hypogonadism that accompanies normal aging is responsible for GHRH deficiency. We assessed the suppressibility of spontaneous and GHRH-stimulated GH secretion by a specific competitive GHRH receptor antagonist in seven elderly (61-76 yr old) and six young (20-23 yr old) healthy nonobese men. Elderly men then received transdermal T (5 mg/d) for 5-6 wk and had the same experiment repeated. Mean final total T, free T, and dihydrotestosterone increased in elderly men [521.5 +/- 56.3 vs. 395.4 +/- 57.2 ng/dl (P = 0.021), 13.8 +/- 1.3 vs. 10.1 +/- 1.7 pg/ml (P = 0.017), and 71.4 +/- 8.9 vs. 41 +/- 8.1 ng/dl (P = 0.004), respectively] to the levels found in their younger controls, but estradiol did not change (19.1 +/- 2.5 vs. 18.5 +/- 2.9 pg/ml; P = 0.67). GH pulse frequency or amplitude and maximum GH were not altered, and the integrated GH concentrations actuall...Continue Reading

Citations

Apr 9, 2009·The Journal of Clinical Endocrinology and Metabolism·Johannes D Veldhuis, Cyril Y Bowers
Mar 6, 2007·Endocrinology and Metabolism Clinics of North America·Naila Goldenberg, Ariel Barkan
Jun 7, 2007·American Journal of Physiology. Endocrinology and Metabolism·Ranganath MuniyappaMarc R Blackman
Jun 26, 2020·International Journal of Urology : Official Journal of the Japanese Urological Association·Keisuke IshikawaShigeo Horie
Mar 22, 2012·Endocrine Reviews·Manthos G GiannoulisPeter Sonksen

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