Effects of serotonin on gonadotropin and growth hormone release from in vitro perifused goldfish pituitary fragments.

GUSTAVO M SOMOZA; RICHARD E PETER; GUSTAVO M SOMOZA

GENERAL AND COMPARATIVE ENDOCRINOLOGY

ACADEMIC PRESS INC ELSEVIER SCIENCE

Año: 1991 vol. 82 p. 103 - 110

0016-6480

The effects of serotonin (S-HT) on gonadotropin and growth hormone release from perifused goldfish (Carassias auratus, L.) pituitary glands were studied. Serotonin, at micromolar concentrations, caused a dose-related release of gonadotropin and an inhibition of growth hormone release in pituitaries from goldfish at different sexual stages. At lower concentrations 5-HT continued to inhibit growth hormone release, but had no effects on gonadotropin release. The stimulatory effects of 5-HT on gonadotropin release could be blocked by ketanserin and cyproheptadine; however, these two antagonists had no effects on 5-HT inhibition of growth hormone release. Perifusion with melatonin had no effect on the release of gonadotropin or growth hormone release. These results demonstrate that 5-HT has a stimulatory effect on gonadotropin secretion, probably through a S-HT, receptor type, and an inhibitory effect on growth hormone through an unidentified receptor type. We hypothesize that the effects on gonadotropin release are due to direct actions on gonadotrophs, whereas the effects on growth hormone release may be due to stimulation of somatostatin release from neurosecretory terminals in the pituitary.