title: Hypoxia promotes progesterone synthesis during luteinization in bovine granulosa cells.
abstract: To determine whether hypoxia has an effect on luteinization, we examined the influence of hypoxia on a model of bovine luteinizing and non-luteinizing granulosa cell culture. The granulosa cells were obtained from small antral follicles (≤ 6 mm in diameter). To induce luteinization, the cells were treated for 24 h with insulin (2 µg/ml), forskolin (10 µM) or insulin in combination with forskolin at 20% O2. After 24 h, progesterone (P4) production was higher in the treated cells, which we defined as luteinizing granulosa cells, than in non-treated cells, which we defined as non-luteinizing granulosa cells. P4 production by non-luteinizing granulosa cells was not affected by hypoxia (24 h at 10% and 5% O2), while P4 production by granulosa cells treated with insulin in combination with forskolin was significantly increased under hypoxia (24 h at 10% and 5% O2). Because hypoxia affected P4 production by the luteinizing granulosa cells but not by the non-luteinizing granulosa cells, hypoxia seems to promote P4 production during, rather than before, luteinization. In the cells treated with insulin in combination with forskolin, mRNA and protein expression of steroidogenic acute regulatory protein (StAR) and protein expression of 3β-hydroxysteroid dehydrogenase (3β-HSD) increased under 10% O2, while mRNA and protein expressions of key protein and enzymes in P4 biosynthesis did not increase under 5% O2. The overall results suggest that hypoxia plays a role in progressing and completing the luteinization by enhancing P4 production through StAR as well as 3β-HSD expressions in the early time of establishing the corpus luteum.
authors.affiliation: Laboratory of Reproductive Physiology, Graduate School of Environmental and Life Science, Okayama University, Okayama 700-8530, Japan.
authors.lastname: Fadhillah
authors.forename: Shin
authors.initials: S
authors.lastname: Yoshioka
authors.forename: Ryo
authors.initials: R
authors.lastname: Nishimura
authors.forename: Kiyoshi
authors.initials: K
authors.lastname: Okuda
mesh_terms: D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D002417:Cattle; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D004305:Dose-Response Relationship, Drug; D005260:Female; D015870:Gene Expression / Q000187:drug effects; D006107:Granulosa Cells / Q000187:drug effects / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D051795:Hypoxia-Inducible Factor 1, alpha Subunit / Q000235:genetics / Q000378:metabolism; D034461:Luteinization / Q000187:drug effects / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011374:Progesterone / Q000096:biosynthesis*; D000098682:Steroidogenic Acute Regulatory Protein
chemical_list: D051795:Hypoxia-Inducible Factor 1, alpha Subunit; D010750:Phosphoproteins; D000098682:Steroidogenic Acute Regulatory Protein; D011374:Progesterone; D015096:3-Hydroxysteroid Dehydrogenases; D002786:Cholesterol Side-Chain Cleavage Enzyme; D010100:Oxygen