Effects of RHC 80267, a diglyceride lipase inhibitor, on prolactin secretion and calcium uptake in GH3 pituitary cells.
The effect of the diglyceride lipase inhibitor RHC 80267 on the prolactin secretory process was examined in clonal anterior pituitary GH3 cells. This compound reduced basal prolactin secretion as well as secretion induced by TRH and phospholipase C but not that induced by phorbol myristate acetate. Although exogenous phospholipase C increased diglyceride, no increase in the products of diglyceride lipase was detected. Moreover, low doses of RHC 80267 were observed to effectively block potassium-stimulated 45calcium influx. It is unlikely that RHC 80267 inhibits prolactin release solely by inhibiting diglyceride lipase. These data suggest blockade of plasma membrane calcium channels as an alternate mechanism for the inhibitory actions of RHC 80267 on intact GH3 cells. These observations may have implications for RHC 80267 action in other cell types.
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D003510:Cyclohexanes / Q000494:pharmacology*; D003512:Cyclohexanones / Q000494:pharmacology*; D008071:Lipoprotein Lipase / Q000037:antagonists & inhibitors*; D010903:Pituitary Gland, Anterior / Q000187:drug effects* / Q000378:metabolism; D011188:Potassium / Q000494:pharmacology; D011388:Prolactin / Q000378:metabolism*; D051381:Rats; D010738:Type C Phospholipases / Q000378:metabolism
D003510:Cyclohexanes; D003512:Cyclohexanones; C036535:1,6-bis(cyclohexyloximinocarbonyl)hexane; D011388:Prolactin; D008071:Lipoprotein Lipase; D010738:Type C Phospholipases; D011188:Potassium; D002118:Calcium