Shortly after superior cervical
ganglionectomy (SCGx) peripheral sympathetic nerve terminals in the median eminence degenerate, the
neurotransmitter is released, and a transient period of increased postsynaptic ensues. The present experiments were undertaken to examine, in the anterograde degeneration paradigm after SCGx, the participation of peripheral sympathetic nerves in feedback regulation of
gonadotropin release in pubertal rats. Groups of 18 days old or 26 days old rats of both sexes were subjected to
castration or its
sham-operation, and 4 h later to SCGx or
sham-SCGx. Twenty-four h later, the rats were decapitated and serum
luteinizing hormone (LH) and
follicle-stimulating hormone (FSH) levels were measured by RIA. In 19 days old male rats, the post-
castration increase of circulating LH, but not of FSH, was prevented by the
wallerian degeneration of sympathetic nerves after acute SCGx. At the 27th day of life, acute SCGx prevented FSH, but not LH, post-
orchidectomy rise. In female rats, SCGx blunted the
oophorectomy-induced increase of
gonadotropin levels at both examined ages. SCGx brought about a significant decrease of serum LH levels in 19 days old,
sham-castrated female rats. At the 19th day of life, acute SCGx decreased serum LH and FSH in neonatally orchidectomized rats, but not in neonatally androgenized female rats. The data are in favor of a negative influence of peripheral sympathetic neurons on
gonadotropin release in prepubertal rats, predominantly in female rats.