Effect of Chronic Secretagogue Exposure on Pro-Adrenocorticotropin/Endorphin Production and Secretion in Primary Cultures of Rat Anterior Pituitary*

摘要: The effects of rat CRF, arginine vasopressin (VP), oxytocin (OXY), and isoproterenol (ISO) on the biosynthesis release pro-ACTH/endorphin-derived peptides by monolayer cultures anterior pituitary cells in complete serum-free medium (CSFM) were studied. When exposed to hormone for 3 h, VP, OXY, ISO each able stimulate secretion immunoactive into culture medium. To determine chronic secretagogue exposure corticotrope function, 14 days, total production was measured immunoassay (cumulative secreted plus cell content). In absence increased 3.6 +/- 0.2-fold (mean SEM) over period from 2-14 days; CRF treatment brought about a 7.9 0.7-fold increase same (P less than 0.0025) or 2.2-fold control cells. Total not affected with VP (100 nM), OXY nM); response unaltered inclusion ISO. examine secretagogues more directly, grown CSFM containing 7 days then incubated radiolabeled amino acid 15 min. newly synthesized pro-ACTH/endorphin quantified immunoprecipitation sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE). Cells 1.9 times labeled that VP. Chronic 8-bromo-cAMP stimulated both synthesis peptides, suggesting capable producing sustained elevation intracellular cAMP levels will prohormone synthesis.