Bradykinin stimulates phosphoinositide metabolism and prolactin secretion in rat anterior pituitary cells.
Bradykinin stimulated prolactin secretion from monolayer cultures of rat anterior pituitary cells, the stimulation being greater from the cells of male rats. This stimulated secretion was accompanied by a rise in total inositol phosphate accumulation, suggesting that the action of bradykinin is mediated by phosphoinositide hydrolysis. The increase in inositol phosphate accumulation was biphasic; a further sharp rise occurred when the concentration of bradykinin exceeded 1 mumol/l. This may indicate that bradykinin acts on other cell types in the pituitary gland. Bradykinin had no effect on growth hormone secretion from cells of normal pituitary glands, or on prolactin secretion and phosphoinositide metabolism in GH3 rat pituitary tumour cells. Bradykinin receptor antagonists (both B1 and B2) had no effect on either bradykinin-stimulated inositol phosphate accumulation or prolactin secretion. Kallikreins, the enzymes responsible for the generation of kinins, are known to be present in the adenohypophysis. Therefore, the results presented here would suggest that kinins may have a role as paracrine agents in the pituitary gland.
Jones
T H
TH
Department of Human Metabolism and Clinical Biochemistry, University of Sheffield Medical School.
Brown
B L
BL
Dobson
P R
PR
D000818:Animals; D001920:Bradykinin / Q000494:pharmacology / Q000502:physiology*; D002478:Cells, Cultured; D005260:Female; D013006:Growth Hormone / Q000378:metabolism; D008297:Male; D010716:Phosphatidylinositols / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000166:cytology / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter / Q000378:metabolism
D010716:Phosphatidylinositols; D018002:Receptors, Bradykinin; D017981:Receptors, Neurotransmitter; D011388:Prolactin; D013006:Growth Hormone; D001920:Bradykinin