Opioidergic control of gonadotropin secretion in the female rabbit: divergent effects of morphine on secretion of follicle-stimulating hormone and luteinizing hormone

The nature of secretion of luteinizing hormone (LH) and follicle-stimulating hormone (FSH) was followed in female rabbits on a daily basis from age 36 to 60 days by sequential 5-min blood sampling over 1- to 2-h periods each day. Both LH and FSH were found to be secreted in a pulsatile manner. The mean LH pulse amplitude over the 25 days was 0.95 +/- 0.32 ng/mL and for FSH it was 10.15 +/- 1.11 ng/mL. Mean plasma LH levels were significantly …