Regulation of aromatase mRNA and estradiol biosynthesis in rat ovarian granulosa and luteal cells by prolactin

• Published in: Molecular endocrinology (Baltimore, Md.) Vol. 4; no. 1; pp. 13 - 21
• Main Authors: KRASNOW, J. S, HICKEY, G. J, RICHARDS, J. S
• Format: Journal Article
• Language: English
• Published: Bethesda, MD Endocrine Society 1990
• Subjects: Animals; Aromatase - biosynthesis; Aromatase - genetics; Biological and medical sciences; Cells, Cultured; Dopamine Agents - pharmacology; Estradiol - biosynthesis; Female; Fundamental and applied biological sciences. Psychology; Gene expression; Gestational Age; Granulosa Cells; Luteal Cells; Molecular and cellular biology; Molecular genetics; Placental Hormones - pharmacology; Pregnancy; Prolactin - pharmacology; Rats; Rats, Inbred Strains; RNA, Messenger - biosynthesis; RNA, Messenger - drug effects; Enzyme; Estrogen; Biosynthesis; Gene expression; Estradiol; Ovarian hormone; Dose activity relation; Northern blotting; Ovary; Regulation(control); Messenger RNA; Ovulatory cycle; Immunoblotting assay; Oestrogen synthase; Granulosa; Sex steroid hormone; Ovarian follicle
• ISSN: 0888-8809; 1944-9917
• DOI: 10.1210/mend-4-1-13

Regulation by PRL of aromatase (P450arom) mRNA and protein and estradiol (E) biosynthesis was examined in granulosa cells during early stages of luteinization in vitro and in vivo. PRL caused a dose-dependent (10-1000 ng/ml) decrease in P450arom mRNA and E biosynthesis (greater than 99%) in luteinized rat granulosa cells in vitro, even when the cells were cultured in the presence of insulin and hydrocortisone (hormones known to synergize with PRL to induce proteins in mammary tissue) or in the presence of forskolin (a nonhormonal stimulator of cAMP). PRL also prevented the marked increases in aromatase mRNA and E biosynthesis stimulated by FSH and forskolin in nonluteinized preovulatory granulosa cells in culture. These effects of PRL on granulosa cells in culture were specific for aromatase and were not observed for other proteins, such as cholesterol side-chain cleavage cytochrome P450 (P450scc) and alpha 2-macroglobulin. PRL also decreased P450arom mRNA and protein during the early stages of luteinization in vivo. PRL administered to rats beginning day 1 postovulation to mimic hormone release during pseudopregnancy reduced the progressive increase in P450arom mRNA occurring in corpora lutea on days 3-4 in ovulated rats not treated with PRL. CB 154, a dopamine agonist that inhibits pituitary release of PRL, caused P450arom mRNA and protein to decrease 50% if given to pregnant rats on days 8-10 of gestation, but increased P450arom mRNA and protein if given to pregnant rats on days 10-12 of gestation. These diverse effects of PRL in pregnancy suggest that placental factors may modify the response of luteal cells to PRL during gestation.