Pituitary response to LHRH during chronic renal insufficiency in the male rat

Chronic renal insufficiency was induced in young adult male rats by a 2-step 5/6 nephrectomy. Four weeks after surgery the rats were anesthetized with ketamine and injected with saline or 1, 5, 10, 50, or 100 ng of LHRH/100 g BW and blood samples were collected at various times and assayed for LH. A second group of rats was injected with saline or 5, 10, 50, 100, or 200 ng of LHRH/100 g BW and serum samples assayed for FSH. A third experiment tested for the presence of a self-priming effect of LHRH on LH secretion. Rats were primed with three iv injections of 10 ng of LHRH/100 g BW or saline at 30-min intervals and challenged with 50 ng of LHRH/100 g BW 30 min after the last priming injection. Ten min after the challenge injection, the LH increment was determined. The data indicate that male rats suffering from chronic renal insufficiency have an impaired LH response to low doses of LHRH, essentially normal FSH responses to most doses of LHRH examined, and lack a self-priming effect of LHRH on LH secretion. These results suggest that part of the reproductive abnormalities found in chronic renal failure may be due to alterations in pituitary LH responses.