The effect of a single injection of testosterone propionate and estradiol benzoate on the LH-RH induced release of FSH and LH in the male rat.

Male adult, intact rats were treated with 1000 or 2000 mug/kg testosterone propionate (TP), 500 or 1000 mug/kg estradiol benzoate (EB) or ol. arachidis only. 30 min, 24h, 48h and 7 days later they were injected with 5 mug/kg LH-RH or saline solution. 30 min after this FSH, LH and testosterone were determined in plasma by radioimmunoassay. It is shown that pretreatment with 500 mug/kg TP enhances significantly the FSH release after LH-RH even on day 7, while the greater dose of TP does not significantly affect the release of FSH. The LH-RH induced release of LH is also increased by the pretreatment with 500 mug/kg TP, while 2000 mug/kg TP do not alter the reaction to LH-RH. EB in both doses does not influence the LH-RH induced release of FSH and LH.