title: Suppression of 20 alpha-hydroxysteroid dehydrogenase activity in cultured rat luteal cells by prolactin.
abstract: 20alpha-Hydroxysteroid dehydrogenase (20 alpha-SDH) activity increases in the cycling corpus luteum of the rat, beginning at 14.00 h on the day of diestrus, but remains low in corpora lutea of pregnancy throughout the first 19 days of gestation. When cells derived from 7-day-old corpora lutea of pregnant rats were cultured for 7 or 12 days, there was a spontaneous rise in 20 alpha-SDH activity from an initial value of 0.44 +/- 0.27 to 4.1 +/- 0.7 units/mg supernatant protein. Addition of LH (NIH-S-18; 2.0 mug/ml) or prostaglandin F2alpha (2.8 X 10(-5) M) to the medium from day 4 to the end of incubation period caused a slight but significant reduction in 20 alpha-SDH activity (20%, P less than 0.05). Supplementation of the medium with ovine prolactin (HIH-P-S11; 10.0 mug/ml) from the time of seeding or from the 2nd to 4th day of culture reduced the activity of 20 alpha-SDH measured on day 12 by 61% (P less than 0.001). This finding suggests that the suppression of 20 alpha-SDH by prolactin, hitherto demonstrated only in vivo results from a direct action of the hormone on the luteal cell.
mesh_terms: D000818:Animals; D003338:Corpus Luteum / Q000201:enzymology*; D003864:Depression, Chemical; D005260:Female; D006913:Hydroxysteroid Dehydrogenases / Q000378:metabolism*; D008184:Luteal Cells / Q000166:cytology / Q000201:enzymology*; D007986:Luteinizing Hormone / Q000494:pharmacology; D011247:Pregnancy; D011388:Prolactin / Q000494:pharmacology*; D011460:Prostaglandins F / Q000494:pharmacology; D051381:Rats; D013997:Time Factors
chemical_list: D011460:Prostaglandins F; D011388:Prolactin; D007986:Luteinizing Hormone; D006913:Hydroxysteroid Dehydrogenases