title: Further studies on in vitro steroidogenesis by luteal cells from long-term hypophysectomized rats.
abstract: Immature pregnant mare's serum gonadotropin-treated rats were hypophysectomized on the day of ovulation (Day 1 of luteal function), and luteal steroidogenesis and human chorionic gonadotropin (hCG) and prolactin (Prl) binding sites were determined on Days 5, 10, 20 and 30 (H5- H30 ) compared with intact rats on Days 5 or 10 (C5 or C10). On H5, dispersed luteal cells secreted large amounts of progesterone (P), 20 alpha-dihydroprogesterone (20 alpha-DHP), 17 alpha-hydroxyprogesterone (17 alpha-OHP), and small amounts of testosterone (T) and estradiol-17 beta (E2), but between H10 and H30 , reduced levels of all steroids were produced except for 20 alpha-DHP. Addition of large amount of pregnenolone (P5) or P (100-1000 ng) to dispersed luteal cells increased production of P and 20 alpha-DHP in C5 and H5 rats. The higher serum levels and basal in vitro production of 20 alpha-DHP from H5 to H30 indicates that 20 alpha-oxidoreductase persists in the corpora lutea (CL) at high levels and that 3 beta-ol-dehydrogenase is also present but with P rapidly shunted into its principal metabolite. From H5 to H30 , addition of 10 ng P to luteal cells increased the production of 17 alpha-OHP and addition of 10 ng androstenedione (A) or T enhanced production of T and E2, indicating that 17 alpha-oxidoreductase, 17 beta-hydroxysteroid dehydrogenase and aromatase also persist in the CL. In vitro addition of 10 ng LH significantly stimulated production of P from luteal cells on C5 and H5, whereas on C10 and H10, 100 ng LH was required and on H20 and H30 , 1 microgram LH produced a minimal increase in P.(ABSTRACT TRUNCATED AT 250 WORDS)
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D004092:20-alpha-Dihydroprogesterone / Q000096:biosynthesis; D000818:Animals; D006063:Chorionic Gonadotropin / Q000378:metabolism; D003338:Corpus Luteum / Q000378:metabolism*; D004958:Estradiol / Q000096:biosynthesis; D005260:Female; D012739:Gonadal Steroid Hormones / Q000096:biosynthesis*; D006908:Hydroxyprogesterones / Q000096:biosynthesis; D007016:Hypophysectomy; D008184:Luteal Cells / Q000187:drug effects / Q000378:metabolism*; D007986:Luteinizing Hormone / Q000494:pharmacology; D011284:Pregnenolone / Q000494:pharmacology; D011374:Progesterone / Q000096:biosynthesis* / Q000494:pharmacology; D011388:Prolactin / Q000378:metabolism; D051381:Rats; D013739:Testosterone / Q000096:biosynthesis
chemical_list: D006063:Chorionic Gonadotropin; D012739:Gonadal Steroid Hormones; D006908:Hydroxyprogesterones; D004092:20-alpha-Dihydroprogesterone; D013739:Testosterone; D011374:Progesterone; D004958:Estradiol; D019326:17-alpha-Hydroxyprogesterone; D011284:Pregnenolone; D011388:Prolactin; D007986:Luteinizing Hormone