Acetylcholine stimulates growth hormone secretion, phosphatidyl inositol labelling, 45Ca2+ efflux and cyclic GMP accumulation in bovine anterior pituitary glands.
Acetylcholine (25 micromol/l) in the presence of the choline esterase inhibitor physostigmine (67 micromol/l) increased the release of growth hormone and efflux of 45Ca2+ from perifused bovine pituitary slices; the time taken for the maximal response to occur was the same. In batch incubations, acetylcholine (1 micromol/l--1 mmol/l) increased pituitary cyclic GMP concentrations in the pituitary gland within 2 min, and increased incorporation of [3H]inositol and [32P]phosphate into pituitary phosphatidyl inositol within 15 min. Cyclic AMP concentrations were not significantly changed 2 or 5 min after acetylcholine addition. All the tissue responses were inhibited by prior exposure of the tissue to atropine (1 micromol/l) but not by tubocurarine (10 micromol/l--1mmol/l), indicating that the responses were mediated by receptors of the muscarinic type. The similarities between these responses and those to known hypothalamic hypophysiotrophic hormones are discussed.
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D001285:Atropine / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002417:Cattle; D006152:Cyclic GMP / Q000096:biosynthesis*; D013006:Growth Hormone / Q000378:metabolism*; D066298:In Vitro Techniques; D010716:Phosphatidylinositols / Q000378:metabolism*; D010830:Physostigmine / Q000494:pharmacology; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D012636:Secretory Rate / Q000187:drug effects; D013268:Stimulation, Chemical; D014403:Tubocurarine / Q000494:pharmacology
D010716:Phosphatidylinositols; D001285:Atropine; D013006:Growth Hormone; D010830:Physostigmine; D006152:Cyclic GMP; D000109:Acetylcholine; D002118:Calcium; D014403:Tubocurarine