|
|
||||||||
Department of Animal Science, Oklahoma State University, Stillwater, Oklahoma 74078, USA
1 Department of Obstetrics and Gynecology, Stanford University School of Medicine, Stanford, California 94305-5317, USA
(Requests for offprints should be addressed to L J Spicer; Email: igf1Leo{at}okstate.edu)
In addition to gonadotropins, steroidogenesis and proliferation of granulosa cells during follicular development are controlled by a number of intraovarian factors including growth differentiation factor-9 (GDF-9), bone morphogenetic protein-4 (BMP-4), and IGF-I. The objective of this study was to determine the effect of GDF-9 and BMP-4 and their interaction with IGF-I and FSH on ovarian granulosa cell function in cattle. Granulosa cells from small (15 mm) and large (822 mm) follicles were collected from bovine ovaries and cultured for 48 h in medium containing 10% fetal calf serum and then treated with various hormones in serum-free medium for an additional 48 h. We evaluated the effects of GDF-9 (150600 ng/ml) and BMP-4 (30 ng/ml) during a 2-day exposure on hormone-induced steroidogenesis and cell proliferation. In FSH plus IGF-I-treated granulosa cells obtained from small follicles, 300 ng/ml GDF-9 reduced (P<0.05) progesterone production by 15% and 600 ng/ml GDF-9 completely blocked (P<0.01) the IGF-I-induced increase in progesterone production. In comparison, 300 and 600 ng/ml GDF-9 decreased (P<0.05) estradiol production by 27% and 71% respectively, whereas 150 ng/ml GDF-9 was without effect (P>0.10). Treatment with 600 ng/ml GDF-9 increased (P<0.05) numbers (by 28%) of granulosa cells from small follicles. In the same cells treated with FSH but not IGF-I, co-treatment with 600 ng/ml GDF-9 decreased (P<0.05) progesterone production (by 28%), increased (P<0.05) cell numbers (by 60%), and had no effect (P>0.10) on estradiol production. In FSH plus IGF-I-treated granulosa cells obtained from large follicles, GDF-9 caused a dose-dependent decrease (P<0.05) in IGF-I-induced progesterone (by 1348%) and estradiol (by 2051%) production. In contrast, GDF-9 increased basal and IGF-I-induced granulosa cell numbers by over 2-fold. Furthermore, treatment with BMP-4 also inhibited (P<0.05) steroidogenesis by 2742% but had no effect on cell numbers. To elucidate downstream signaling pathways, granulosa cells from small follicles were transfected with similar to mothers against decapentaplegics (Smad) binding element (CAGA)- or BMP response element (BRE)-promoter reporter constructs. Treatment with GDF-9 (but not BMP-4) activated the Smad3-induced CAGA promoter activity, whereas BMP-4 (but not GDF-9) activated the Smad1/5/8-induced BRE promoter activity. We have concluded that bovine granulosa cells are targets of both GDF-9 and BMP-4, and that oocyte-derived GDF-9 may simultaneously promote granulosa cell proliferation and prevent premature differentiation of the granulosa cells during growth of follicles, whereas theca-derived BMP-4 may also prevent premature follicular differentiation.
This article has been cited by other articles:
![]() |
L. J Spicer, P. Y Aad, D. T Allen, S. Mazerbourg, A. H Payne, and A. J Hsueh Growth Differentiation Factor 9 (GDF9) Stimulates Proliferation and Inhibits Steroidogenesis by Bovine Theca Cells: Influence of Follicle Size on Responses to GDF9 Biol Reprod, February 1, 2008; 78(2): 243 - 253. [Abstract] [Full Text] [PDF] |
||||
![]() |
A. Bettegowda, J. Yao, A. Sen, Q. Li, K.-B. Lee, Y. Kobayashi, O. V. Patel, P. M. Coussens, J. J. Ireland, and G. W. Smith JY-1, an oocyte-specific gene, regulates granulosa cell function and early embryonic development in cattle PNAS, November 6, 2007; 104(45): 17602 - 17607. [Abstract] [Full Text] [PDF] |
||||
![]() |
J Buratini Jr., M.G.L Pinto, A.C Castilho, R.L Amorim, I.C Giometti, V.M Portela, E.S Nicola, and C.A Price Expression and Function of Fibroblast Growth Factor 10 and Its Receptor, Fibroblast Growth Factor Receptor 2B, in Bovine Follicles Biol Reprod, October 1, 2007; 77(4): 743 - 750. [Abstract] [Full Text] [PDF] |
||||
| HOME | HELP | CONTACT US | SUBSCRIPTIONS | ARCHIVE | SEARCH | TABLE OF CONTENTS |