Saponin effects of prolactin-like stimulation of ornithine decarboxylase activity in mouse mammary gland explants.
Saponin, a naturally occurring plant glycoside, was found to elicit a prolactin-like stimulation of ornithine decarboxylase (ODC) activity in mouse mammary gland explants. A dose-response activation of ODC was observed with saponin at concentrations between 2 and 10 micrograms/ml. At concentrations of 10 and 15 micrograms/ml, saponin effected a response similar to that of PRL; when tested in concert, PRL and saponin caused a nonadditive response. The time-course of the saponin and PRL effects on ODC activation were not different; a maximum response occurred 2-4 hours after addition of saponin. The saponin and PRL responses were abolished by antibiotics (puromycin and cyclohexamide) that inhibit protein synthesis, but not by actinomycin D which inhibits RNA synthesis. Finally, saponin, by itself, did not affect the rate of milk product formation, but at higher concentrations (above 0.5 microgram/ml) impaired the PRL stimulation of lipid and casein synthesis.
Koduri
P B
PB
Department of Physiology, Wayne State University School of Medicine, Detroit, Michigan.
Rillema
J A
JA
D000818:Animals; D002364:Caseins / Q000096:biosynthesis; D003513:Cycloheximide / Q000494:pharmacology; D003609:Dactinomycin / Q000494:pharmacology; D004305:Dose-Response Relationship, Drug; D005260:Female; D007700:Kinetics; D007774:Lactation / Q000187:drug effects; D008055:Lipids / Q000096:biosynthesis; D008321:Mammary Glands, Animal / Q000187:drug effects / Q000201:enzymology*; D051379:Mice; D009955:Ornithine Decarboxylase / Q000378:metabolism*; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology*; D011691:Puromycin / Q000494:pharmacology; D012503:Saponins / Q000008:administration & dosage / Q000494:pharmacology*
D002364:Caseins; D008055:Lipids; D012503:Saponins; D003609:Dactinomycin; D011691:Puromycin; D011388:Prolactin; D003513:Cycloheximide; D009955:Ornithine Decarboxylase