Studies on the pituitary responsiveness to luteinizing hormone-releasing hormone (lh-rh) in intact male rats of different ages

The pituitary response to a punned porcine LH-RH was investigated in male rats of IS, 25, 30, 35, 45, 60, and 240 days of age. Significant amounts of LH were released after administration of LH-RH in all the ages studied. The maximal response was seen, however, between 35 and 45 days of age, the lowest being at 15 and 240 days of age. No evidence of pituitary LH depletion after LH-RH was observed in any of the groups studied. LH-RH elicited a significant FSH release at 25, 30, 35, and 45 days of age. No significant FSH release was observed at 15, 60, and 240 days of age. The maximal response in terms of FSH release was recorded between 25 and 35 days of age. No apparent pituitary FSH depletion could be seen after LH-RH administration in any of the groups studied.