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.
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.
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
D002364:Caseins; D012313:RNA; D011388:Prolactin; D013006:Growth Hormone; D002262:Carboxy-Lyases; D009955:Ornithine Decarboxylase; D007930:Leucine; D014529:Uridine