title: Depletion of pituitary prolactin by cysteamine is due to loss of immunological activity.
abstract: The mechanism by which cysteamine reduces the PRL content of pituitary cells was studied in primary cultures of estradiol-induced pituitary tumors in Fischer 344 rats. The PRL content of these cells was effectively decreased by cysteamine, with an IC50 of 0.2 mM. Cells previously labeled with [3H]leucine were exposed to cysteamine (0.25 mM), and the intracellular content of [3H]PRL was measured by immunological or nonimmunological means, that is by immunoprecipitation and electrophoresis or by electrophoresis alone. The intracellular concentration of immunoreactive [3H]PRL was reduced by 53% by cysteamine, whereas [3H]PRL quantified by electrophoresis alone was not significantly affected. Our data indicate that cysteamine reduces the PRL content of pituitary tumor cells by causing the loss of its immunoreactivity.
mesh_terms: D000818:Animals; D002478:Cells, Cultured; D003543:Cysteamine / Q000494:pharmacology*; D005260:Female; D007106:Immune Sera; D007118:Immunoassay; D010911:Pituitary Neoplasms / Q000378:metabolism*; D011388:Prolactin / Q000276:immunology / Q000378:metabolism*; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D007106:Immune Sera; D003543:Cysteamine; D011388:Prolactin