Effects of pretreatment with tetradecanoyl phorbol acetate on regulation of growth hormone and prolactin secretion from ovine anterior pituitary cells.
Tetradecanoyl phorbol acetate (TPA) stimulates growth hormone (GH) and prolactin secretion from ovine anterior pituitary cells. Pretreatment of the cells with TPA abolishes this effect, presumably due to down-regulation of protein kinase C. Such pretreatment did not alter effects of thyrotropin-releasing hormone or dopamine on prolactin secretion, suggesting no involvement of protein kinase C. Pretreatment with TPA attenuated actions of GH-releasing hormone on GH release (but not actions on cyclic AMP levels), possibly due to depletion of cellular stores of GH. Such pretreatment also attenuated inhibition of GH release by somatostatin, possibly due to phosphorylation of receptors or associated proteins by protein kinase C.
Boyd
R S
RS
Biochemistry Laboratory, School of Biological Sciences, University of Sussex, Falmer, Brighton, England.
Wallis
M
M
D000818:Animals; D002478:Cells, Cultured; D000242:Cyclic AMP / Q000378:metabolism; D004298:Dopamine / Q000494:pharmacology; D007987:Gonadotropin-Releasing Hormone / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D010903:Pituitary Gland, Anterior / Q000187:drug effects / Q000378:metabolism*; D011388:Prolactin / Q000378:metabolism*; D011493:Protein Kinase C / Q000378:metabolism; D012756:Sheep; D013755:Tetradecanoylphorbol Acetate / Q000494:pharmacology*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology
D007987:Gonadotropin-Releasing Hormone; D013973:Thyrotropin-Releasing Hormone; D011388:Prolactin; D013006:Growth Hormone; D000242:Cyclic AMP; D011493:Protein Kinase C; D013755:Tetradecanoylphorbol Acetate; D004298:Dopamine