Direct effects of a luteinizing hormone-releasing hormone agonist on intratesticular levels of testosterone and interstitial fluid formation in intact male rats.

Abstract

The direct effects of an LHRH agonist (LHRHA) on testicular interstitial fluid (IF) formation and IF levels of testosterone were studied in intact male rats aged 55-87 days. Under ether anesthesia, doses of LHRH-A ranging from 0.1-10 ng were injected into the right (R) testis, whereas the left (L) testis was injected with the injection vehicle and used to control for any peripheral effects of LHRH-A resulting from pituitary LH release. Overall control animals were injected in both R and L testes with vehicle alone. LHRH-A caused a significant (P < 0.001) and dose-dependent increase in levels of testosterone in IF from the R but not from the L (control) testis at 2-6 h after injection. With lower doses of LHRH-A (0.1-1 ng), this increase occurred in the absence of any increase in serum LH levels. In contrast, injection of 10 ng LHRH-A caused sustained LH release, and although this led to a massive increase in the IF levels of testosterone in the L (control) testis, levels in IF from the R (LHRH-A injected)...