title: Effect of various concentrations of prolactin and growth hormone on the magnitude of stimulation of RNA synthesis, casein synthesis and ornithine decarboxylase activity in mouse mammary gland explants.
abstract: The effects of various concentrations of prolactin and growth hormone on the rates of [3H]-uridine incorporation into RNA, [3H]-leucine incorporation into casein, and ornithine decarboxylase (ODC) activity were determined in mouse mammary gland explants. The lowest concentrations of prolactin which produced significant responses were between 5 and 25 ng/ml. Growth hormone, in contrast, produced significant response at concentrations between 250 and 1,000 ng/ml. The prolactin actions on RNA and casein synthesis were essentially all-or-none type responses, i.e. the magnitude of the responses were maximal at about 10 ng/ml prolactin. The action of prolactin on ODC activity was quite different; a concentration-response relationship was observed with prolactin at concentrations from 10 t 250 ng/ml. It is apparent from these studies that different concentrations of prolactin are required to produce optimal actions on different biochemical parameters in cultured mammary tissues.
mesh_terms: D000818:Animals; D002262:Carboxy-Lyases / Q000378:metabolism*; D002364:Caseins / Q000096:biosynthesis*; D046508:Culture Techniques; D004305:Dose-Response Relationship, Drug; D005260:Female; D013006:Growth Hormone / Q000494:pharmacology*; D007930:Leucine / Q000378:metabolism; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000378:metabolism*; D051379:Mice; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology*; D012313:RNA / Q000096:biosynthesis*; D014529:Uridine / Q000378:metabolism
chemical_list: D002364:Caseins; D012313:RNA; D011388:Prolactin; D013006:Growth Hormone; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; D007930:Leucine; D014529:Uridine