Binding of prostaglandin E2 to cultured bovine adrenal chromaffin cells and its effect on catecholamine secretion.
We have previously shown that plasma membranes from adrenal medulla possess specific high-affinity binding sites for prostaglandins (PGs) E1 and E2. We have now investigated the binding of PGE2 to intact bovine adrenal chromaffin cells and the effects of prostaglandins on the release of catecholamines from these cells. Adrenal chromaffin cells specifically bound PGE2 with a dissociation constant of 2 nM and a concentration of about 40,000 binding sites per cell. Low concentrations of PGE2 inhibited the nicotine-stimulated release of catecholamines from these cells. The effect of PGE2 was biphasic, the maximal inhibitory effect being observed at a concentration of between 1 and 10 nM. Higher concentrations (1 microM) of PGE2 had minimal inhibitory effects on nicotine-evoked noradrenaline release, but instead had a direct stimulatory effect in the absence of cholinergic agonists. Although the stimulatory effects of high concentrations of PGE2 were reproducibly observed in all cell preparations, only about one-half of the cultures tested responded to the inhibitory effects of this prostaglandin. It is possible that PGE2 plays a modulatory role in the regulation of catecholamine secretion from the adrenal medulla.
Karaplis
A C
AC
Endocrine Laboratory, Royal Victoria Hospital, Montreal, Quebec, Canada.
Funk
C D
CD
Powell
W S
WS
D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002837:Chromaffin Granules / Q000378:metabolism*; D002838:Chromaffin System / Q000378:metabolism*; D000242:Cyclic AMP / Q000032:analysis; D015232:Dinoprostone / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D019204:GTP-Binding Proteins / Q000502:physiology; D009538:Nicotine / Q000494:pharmacology; D009638:Norepinephrine / Q000378:metabolism*; D010716:Phosphatidylinositols / Q000378:metabolism; D011453:Prostaglandins / Q000494:pharmacology
D010716:Phosphatidylinositols; D011453:Prostaglandins; D009538:Nicotine; D000242:Cyclic AMP; D019204:GTP-Binding Proteins; D015232:Dinoprostone; D009638:Norepinephrine