Skip to main content
ARS Home » Research » Publications at this Location » Publication #101900
Title: MODULATION OF IN VITRO DNA SYNTHESIS IN THE CHICKEN OVARIAN GRANULOSA CELL FOLLICULAR HIERARCHY BY FOLLICLE-STIMULATING HORMONE AND LUTEINZING HORMONE

Author
item MCELROY, A - TEXAS A&M UNIVERSITY
item CALDWELL, D - TEXAS A&M UNIVERSITY
item Proudman, John
item HARGIS, B - TEXAS A&M UNIVERSITY

Submitted to: Poultry Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 10/20/2003
Publication Date: 1/1/2004
Citation: Mcelroy, A.P., Caldwell, D.J., Proudman, J.A., Hargis, B.M. 2004. Modulation of in vitro DNA synthesis in the chicken ovarian granulosa cell follicular hierarchy by follicle-stimulating hormone and luteinzing hormone. Poultry Science. 83:500-506.

Interpretive Summary: The bird ovary contains a series of follicles awaiting ovulation but, unlike mammals, ovarian follicles are arranged in a hierarchy of size in the bird, such that a follicle may mature and be ovulated each day. The frequency with which follicles enter and pass through this hierarchy determines the rate of egg production, but this process is poorly understood. Luteinizing hormone (LH) and follicle-stimulating hormone (FSH) are critical to regulating the growth and ovulation of follicles. LH stimulates progesterone production by the largest follicle (F1), leading to ovulation. The most commonly hypothesized role for FSH, which apparently has weak effects on production of steroid hormones in large follicles, is one of stimulation of growth of the follicles and maintenance of the hierarchical size of the follicles. Since the growing follicle undergoes a five-fold increase in the number of granulosa cells during the 5 to 7 days prior to ovulation, the present study was conducted to determine whether L or FSH influence the proliferation of these cells. Results showed that both ovine and chicken FSH markedly stimulate DNA synthesis in granulosa cells from the F1 follicle, indicative of a stimulation of cell proliferation. Ovine LH was maximally effective at a dose of 10 ng/ml or less, and was approximately 10 times more potent than chicken FSH. Neither ovine LH nor chicken LH showed any effect on granulosa cell proliferation at doses up to 100 ng/ml. These findings indicate a mechanism by which FSH may reduce hatching egg production by either slowing follicle growth or causing multiple hierarchies. These results may also be used by scientists to develop a sensitive and specific bioassay for FSH.

Technical Abstract: The steroidogenic profile of ovarian follicles in the domestic hen preovulatory hierarchy has been partially characterized, however, the factor(s) responsible for the growth of the follicle and the contributing granulosa cell proliferation have not yet been fully described, particularly concerning the role of follicle-stimulating hormone (FSH) may play. In the present study, F1 ovarian follicles were collected from Single Comb White Leghorn hens and the effects of ovine or chicken derived FSH (oFSH or cFSH) or luteinizing hormone (oLH or cLH) on granulosa cell progesterone or tritiated thymidine incorporation, indicative of DNA synthesis, were evaluated. Consistent with previous reports, oLH significantly (P<0.05) stimulated progesterone synthesis by granulosa cells from the F1 follicle in a concentration-related manner. However, oFSH resulted in progesterone production only at the highest concentration (100 ng/ml) evaluated. Conversely, oFSH or cFSH significantly and consistently stimulated DNA synthesis by F1 granulosa cells in a concentration-related manner, as compared to basal levels of DNA synthesis within cell pools. In contrast to the oLH-stimulated progesterone synthesis, neither oLH nor cLH caused marked or consistent changes in granulosa cell DNA synthesis. These in vitro data support the proposed role for FSH in granulosa cell proliferation, possibly contributing to follicle growth, and suggest that in vitro incorporation of tritiated thymidine by granlosa cells from the F1 follicle may provide a sensitive and selective bioassay for chicken gonadotropin preparations.