Serotonin and acetylcholine affect the release of prolactin and growth hormone from pituitary glands of domestic fowl in vitro in the presence of hypothalamic tissue

Abstract

Anterior pituitary glands from broiler fowl were incubated alone or with hypothalamic tissue in medium containing either serotonin or serotoninergic drugs, acetylcholine or cholinergic drugs, and the release of prolactin (Prl) and growth hormone (GH) measured by homologous radioimmunoassays. The neurotransmitters and drugs affected the release of hormones from the pituitary gland only when hypothalamic tissue was also present. Serotonin and its agonist quipazine stimulated the release of Prl and inhibited release of GH in a concentration-related manner. The antagonist methysergide blocked the effects of serotonin and quipazine on Prl. Acetylcholine and its agonist pilocarpine also stimulated release of Prl and inhibited release of GH in a concentration-related manner. Atropine blocked these responses. The results show that serotonin and acetylcholine affect pituitary hormone secretion by acting on the hypothalamus. They may stimulate the secretion of a Prl releasing hormone and somatostatin.

Effect of Aging on the Activities of Acetylcholinesterase, Na+, K+-ATPase and Mg2+-ATPase in Rat Pituitary and Hypothalamus

“…Moreover, endocrine responses were greater in older subjects than young subjects for CRH, ACTH, beta-endorphin and cortisol (Peskind et al, 1995). This age-related choliner gic activity decrease may result in stimulation of somatostatin, inactivation of growth hormonereleasing hormone (GH RH ) and prolactin secre tion by acting on the hypothalamus (Hall et al, 1984;Muller et al, 1995) and modulation of neu rohypophysial vasopressin secretion (Michels et a l, 1991).…”

Stimulation of Growth Hormone Release by 5-Hydroxytryptamine (5-HT) in Cultured Rat Anterior Pituitary Cell Aggregates: Evidence for Mediation by 5-HT2B, 5-HT7, 5-HT1B, and Ketanserin-Sensitive Receptors

“…5-HT affects GH release through the serotoninergic projections from the medial and dorsal raphe nucleus of the brain stem to the hypothalamus (4). In vivo-manipulated 5-HT neurotransmission or treatment with serotonin agonists or antagonists suggests a stimulatory, inhibitory, no role, or controversial findings of 5-HT in GH release, depending on the physiological condition and species (5)(6)(7)(8)(9)(10)(11)(12)(13)(14)(15)(16)(17)(18)(19). The disparity in findings is probably related to the complexity of the serotoninergic system and the many receptor subtypes involved.…”

Evaluation of quaternized and neutral muscarinic receptor ligands in normal and DES-treated rat

“…Further characterization of this model verified the increases in serum prolactin levels and pituitary weight, and documented increases in percent prolactin secreting cells (Otto et al, 1986a). Although the role of the mAChR receptor in the pituitary has yet to be sharply defined, there is evidence for cholinergic control of prolactin secretion (Carmeliet and Denef, 1988;Hall et al, 1984;Sharif, 1988). Comparison of mAChR antagonist localization in normal rat pituitary with localization in a prolactinoma model might reveal differences in mAChR density that would aid in understanding the role of cholinergic influence in the pituitary.…”