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Updated: Jul 28, 2026
11:51
Combining Behavioral Endocrinology and Experimental Economics: Testosterone and Social Decision Making
Published on: March 2, 2011
Testosterone suppression of the HPT axis
J H MacIndoe1, P J Perry, W R Yates
1Department of Psychiatry, College of Medicine, University of Iowa, Iowa City, USA.
Summary
Androgenic-anabolic steroid injections impair sperm production and suppress key hormones. However, normal male gonadal function and hormone levels fully recovered after stopping the drug.
Area of Science:
- Endocrinology
- Reproductive Medicine
- Pharmacology
Background:
- Mechanisms of androgenic-anabolic steroid (AAS) impact on male gonadal function are not fully understood.
- Previous studies indicate AAS can suppress normal gonadal function in experimental settings.
Purpose of the Study:
- To investigate the effects of varying doses of testosterone cypionate (TC) on male gonadal function.
- To determine the recovery of the hypothalamic-pituitary-testicular axis after TC cessation.
Main Methods:
- Subjects received weekly injections of testosterone cypionate (TC) placebo, followed by TC doses of 100 mg/wk, 250 mg/wk, or 500 mg/wk.
- After active treatment, subjects received 12 weeks of TC placebo injections.
- Hormonal levels (LH, FSH) and pituitary responses to LHRH were monitored.
Main Results:
- Spermatogenesis was impaired at all TC doses, with inconsistent and non-dose-dependent reductions in sperm count.
- Basal luteinizing hormone (LH) and follicle-stimulating hormone (FSH) became undetectable within 2-6 weeks.
- Pituitary gonadotropin responses to LHRH diminished progressively, with LH responses suppressed last.
Conclusions:
- Exogenous testosterone administration significantly suppresses spermatogenesis and the hypothalamic-pituitary-testicular axis.
- Reversal of these inhibitory effects occurred after the cessation of drug treatment.
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