The cAMP-dependent signalling cascade in the two luteal cell types of the pregnant rat corpus luteum.
Corpora lutea of rats, like those of many other species, contain two sub-populations of luteal cells. In this report we sought to determine whether the luteinizing hormone (LH)- and beta-adrenergic cAMP signal transduction pathways known to be present in rat corpora lutea were segregated into separate luteal cell types. Results showed that large rat luteal cells, obtained on day 3 of pregnancy, exhibited elevated LH- and most notably epinephrine-stimulated adenylyl cyclase activities but equivalent cAMP-dependent catalytic protein kinase and total regulatory subunit cAMP binding activities compared to small luteal cells. Progesterone production by the large cell was greater than that by the small cell but both cells were equally sensitive to stimulation of progesterone by LH. However, neither the large nor the small rat luteal cell produced significant progesterone in response to epinephrine despite a marked epinephrine-stimulated adenylyl cyclase in both cell populations. The LH-stimulated progesterone synthetic response of the two sub-populations of rat luteal cells is more similar to that of the developing monkey corpus luteum and contrasts sharply with that of ruminants.
Nelson
S E
SE
Department of Physiology and Biophysics, University of Illinois College of Medicine, IL 60612.
Gibori
G
G
Hunzicker-Dunn
M
M
D000262:Adenylyl Cyclases / Q000378:metabolism; D000818:Animals; D002478:Cells, Cultured; D005576:Colforsin / Q000494:pharmacology; D003338:Corpus Luteum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D000242:Cyclic AMP / Q000378:metabolism / Q000502:physiology*; D004837:Epinephrine / Q000494:pharmacology; D005260:Female; D007986:Luteinizing Hormone / Q000502:physiology; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000378:metabolism*; D011374:Progesterone / Q000096:biosynthesis; D011494:Protein Kinases / Q000378:metabolism; D051381:Rats; D015398:Signal Transduction / Q000502:physiology*
D005576:Colforsin; D011374:Progesterone; D007986:Luteinizing Hormone; D000242:Cyclic AMP; D011494:Protein Kinases; D000262:Adenylyl Cyclases; D004837:Epinephrine