Chronic treatment with LH-RH in golden hamsters.

Male golden hamsters were treated with low doses (50 or 100 ng) or high doses (500-1000 ng) of LH-RH for periods of 10 to 21 days. Gonadal atrophy was induced by blinding. Treatment of intact hamsters with high doses of LH-RH reduced pituitary sensitivity to a test dose of LH-RH given at the end of the experiment. Concomitantly, testis and seminal vesicles were reduced in weight. In blind hamsters with gonadal atrophy, low dose treatment with LH-RH for 21 days reversed testicular atrophy and restored spermatogenesis, while the high dose treatment partly reversed testicular atrophy (viz. increased tubular diameter) but inhibited spermatogenesis. Low dose treatment also increased testicular and seminal vesicles weight in blinded hamsters, whereas high dose treatment did not change these parameters. It is concluded, that a positive effect on testicular functiion may only be obtained by low dose treatment with LH-RH, whereas high dose treatment induces a negative feedback blocking the effect of LH-RH on pituitary gonadotrophin secretion.