Induction of exocytosis in permeabilized pituitary cells by alpha- and beta-type protein kinase C.
Protein kinase C is now recognized to comprise a family of closely related subspecies (PKCs). When cultured rat pituitary cells were permeabilized by digitonin for 5 min in the absence of Ca2+, endogenous PKC activity was decreased by 72%. PKC depletion was also achieved by prior treatment (24 hr) with high concentrations of phorbol 12-myristate 13-acetate (PMA). When purified activated brain PKCs were added for 30 min to PMA-pretreated, digitonin-permeabilized cells, only alpha- and beta- but not gamma-type PKC stimulated luteinizing hormone release. Since PKC was implicated as a mediator of gonadotropin secretion, gonadotropin-releasing hormone might utilize alpha- and beta-type PKCs for stimulation of gonadotropin secretion; alpha- and beta-type PKCs might participate also in other exocytotic responses in diverse biological systems in which PKC was implicated.
Naor
Z
Z
Department of Biochemistry, George S. Wise Faculty of Life Sciences, Tel Aviv University, Ramat Aviv, Israel.
Dan-Cohen
H
H
Hermon
J
J
Limor
R
R
D000818:Animals; D001921:Brain / Q000201:enzymology*; D002463:Cell Membrane Permeability; D002478:Cells, Cultured; D004072:Digitonin; D004789:Enzyme Activation; D005089:Exocytosis / Q000187:drug effects; D005260:Female; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D007527:Isoenzymes / Q000378:metabolism*; D007700:Kinetics; D007986:Luteinizing Hormone / Q000378:metabolism; D008297:Male; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D011919:Rats, Inbred Strains; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology
D007527:Isoenzymes; D007987:Gonadotropin-Releasing Hormone; D007986:Luteinizing Hormone; D011493:Protein Kinase C; D004072:Digitonin; D013755:Tetradecanoylphorbol Acetate