Two pathways of placental lactogen secretion by cultured human trophoblast.
To assess the relative importance of regulated and of constitutive secretion of placental lactogen, a cell culture model of term human trophoblast was utilized. Time courses of secretion revealed a constant secretion rate over 9 days of culture, with relatively small constant intracellular hormone concentration. Potassium, 21 mM, produced a slight but significant increase in hormone secretion into the medium. Growth hormone-releasing hormone (5 X 10(-10)-5 X 10(-9)) stimulated a 27-48% increase in placental lactogen secretion. The data suggest a major process of constitutive secretion and a minor role for regulated secretion from a storage pool.
D002478:Cells, Cultured; D005260:Female; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D006801:Humans; D010928:Placental Lactogen / Q000378:metabolism*; D011188:Potassium / Q000494:pharmacology; D011247:Pregnancy; D014327:Trophoblasts / Q000187:drug effects / Q000378:metabolism*
D013007:Growth Hormone-Releasing Hormone; D010928:Placental Lactogen; D011188:Potassium