Effects of ovarian theca cells on granulosa cell differentiation during gonadotropin-independent follicular growth in cattle.
We investigated the effects of theca cells or FSH on granulosa cell differentiation and steroid production during bovine early follicular growth, using a co-culture system in which granulosa and theca cells were cultured on opposite sides of a collagen membrane. Follicular cells were isolated from early antral follicles (2-4 mm) that were assumed to be in gonadotropin-independent phase and just before recruitment into a follicular wave. Granulosa cells were cultured under serum-free conditions with and without theca cells or recombinant human FSH to test their effects on granulosa cell differentiation. Messenger RNA levels for P450 aromatase (aromatase), P450 cholesterol side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD), LH receptor (LHr), and steroidogenic acute regulatory protein (StAR) in granulosa cells were measured by real-time quantitative RT-PCR analysis. FSH enhanced aromatase mRNA expression in granulosa cells, but did not alter estradiol production. FSH also enhanced mRNA expression for P450scc, LHr, and StAR in granulosa cells, resulting in an increase in progesterone production. In contrast, theca cells enhanced aromatase mRNA expression in granulosa cells resulting in an increase in estradiol production. Theca cells did not alter progesterone production and mRNA expression in granulosa cells for P450scc, 3beta-HSD, LHr, and StAR. The results of the present study indicate that theca cells are involved in both rate-limiting steps in estrogen production, i.e., androgen substrate production and aromatase regulation, and that theca cell-derived factors regulate estradiol and progesterone production in a way that reflects steroidogenesis during the follicular phase of the estrous cycle.
Orisaka
Makoto
M
Department of Obstetrics and Gynecology, University of Fukui, Fukui, Japan.
Mizutani
Tetsuya
T
Tajima
Kimihisa
K
Orisaka
Sanae
S
Shukunami
Ken-ichi
K
Miyamoto
Kaoru
K
Kotsuji
Fumikazu
F
D015096:3-Hydroxysteroid Dehydrogenases / Q000235:genetics / Q000378:metabolism; D000818:Animals; D001141:Aromatase / Q000235:genetics / Q000378:metabolism; D002417:Cattle; D002454:Cell Differentiation / Q000502:physiology*; D049109:Cell Proliferation; D002478:Cells, Cultured; D002786:Cholesterol Side-Chain Cleavage Enzyme / Q000235:genetics / Q000378:metabolism; D018920:Coculture Techniques; D016895:Culture Media, Serum-Free; D003577:Cytochrome P-450 Enzyme System; D005260:Female; D005640:Follicle Stimulating Hormone / Q000235:genetics / Q000378:metabolism; D006062:Gonadotropins / Q000235:genetics / Q000378:metabolism*; D006107:Granulosa Cells / Q000166:cytology / Q000502:physiology*; D006801:Humans; D006080:Ovarian Follicle / Q000166:cytology* / Q000254:growth & development* / Q000378:metabolism; D010750:Phosphoproteins / Q000235:genetics / Q000378:metabolism; D011974:Receptors, LH / Q000235:genetics / Q000378:metabolism; D013799:Theca Cells / Q000166:cytology / Q000378:metabolism*; D000098682:Steroidogenic Acute Regulatory Protein
D016895:Culture Media, Serum-Free; D006062:Gonadotropins; D010750:Phosphoproteins; D011974:Receptors, LH; D000098682:Steroidogenic Acute Regulatory Protein; D005640:Follicle Stimulating Hormone; D003577:Cytochrome P-450 Enzyme System; D015096:3-Hydroxysteroid Dehydrogenases; D001141:Aromatase; D002786:Cholesterol Side-Chain Cleavage Enzyme