Estrous cycle delay and inhibition of gonadotropin and prolactin release during sympathetic nerve degeneration after superior cervical ganglionectomy of rats.

The changes in the activity of the pituitary-gonadal axis during sympathetic nerve degeneration after superior cervical ganglionectomy (SCGx) were examined in female rats. In a first experiment SCGx performed at 24.00 h of diestrus II, 17 h in advance to the critical period for gonadotropin and prolactin (PRL) release, caused a delay of 1 day or more in estrous cyclicity, while SCGx at 24.00 h on estrus did not modify the estrous cycle. In a second experiment ovariectomized rats injected subcutaneously with estradiol-progesterone or vehicle were subjected to SCGx 17 h before the expected maxima in luteinizing hormone (LH), follicle-stimulating hormone (FSH), and PRL serum levels. A significant decrease of serum gonadotropin and PRL concentration was found in SCGx, steroid-treated rats. In a third experiment groups of rats injected with estradiol-progesterone and killed at 15.00, 16.00, 17.00, or 18.00 h at or around the time of maximal FSH, LH, and PRL release were used. SCGx performed 17 h before killing caused a generally depressive effect of LH, FSH, and PRL release. In a fourth experiment ovariectomized rats were subjected to pinealectomy and, 1 week later, to estradiol-progesterone treatment and SCGx as in experiment 2. Pinealectomy did not modify the depression of steroid-induced LH, FSH, and PRL release found during wallerian degeneration of sympathetic nerves after SCGx. In a fifth experiment the effect of alpha 1- and/or beta-adrenoceptor blockade on SCGx-induced inhibition of hormone release was assessed in estradiol-progesterone treated, spayed rats.(ABSTRACT TRUNCATED AT 250 WORDS)