Ovary

Zebrafish Gonadotropins and Their Receptors: I. Cloning and Characterization of Zebrafish Follicle-Stimulating Hormone and Luteinizing Hormone Receptors - Evidence for Their Distinct Functions in Follicle Development

Abstract
In the present study, we cloned and characterized zebrafish FSH receptor (Fshr) and LH receptor (Lhr). Both fshr and lhr were abundantly expressed in the zebrafish gonads; however, they could also be detected in the kidney and liver, respectively. When over-expressed in mammalian cell lines together with a cAMP-responsive reporter gene, zebrafish Fshr responded to goldfish pituitary extract but not hCG, whereas Lhr could be activated by both. It was further demonstrated that Fshr was specific to bovine FSH, while Lhr could be stimulated by both bovine FSH and LH. Low level of fshr expression could be detected in the immature ovary, but the level steadily increased during vitellogenesis of the first cohort of developing follicles. In contrast, the expression of lhr could barely be detected in the immature ovary, but it became detectable at the beginning of vitellogenesis and steadily increased afterwards with the peak level reached at the full-grown stage. At the follicle level, the expression of fshr was very weak in the follicles of primary growth stage, but significantly increased with the follicles entering vitellogenesis. However, after reaching the maximal level in the mid-vitellogenic follicles, the level of fshr expression dropped slightly but significantly at the full-grown stage. In comparison, the expression of lhr obviously lagged behind that of fshr. Its expression became detectable only when the follicles started to accumulate yolk granules, but the level rose steadily afterwards and reached the peak at the full-grown stage prior to oocyte maturation. These results suggest differential roles for Fshr and Lhr in zebrafish ovarian follicle development.

Key words: Ovary • Follicle-stimulating hormone • Follicle-stimulating hormone receptor • Follicular development • Luteinizing hormone

This article has been cited by other articles:

				E. Sambroni, F. Le Gac, B. Breton, and J.-J. Lareyre Functional specificity of the rainbow trout (Oncorhynchus mykiss) gonadotropin receptors as assayed in a mammalian cell line J. Endocrinol., November 1, 2007; 195(2): 213 - 228. [Abstract] [Full Text] [PDF]

				G. Pidoux, P. Gerbaud, O. Marpeau, J. Guibourdenche, F. Ferreira, J. Badet, D. Evain-Brion, and J.-L. Frendo Human Placental Development Is Impaired by Abnormal Human Chorionic Gonadotropin Signaling in Trisomy 21 Pregnancies Endocrinology, November 1, 2007; 148(11): 5403 - 5413. [Abstract] [Full Text] [PDF]

				L. Liu and W. Ge Growth Differentiation Factor 9 and Its Spatiotemporal Expression and Regulation in the Zebrafish Ovary Biol Reprod, February 1, 2007; 76(2): 294 - 302. [Abstract] [Full Text] [PDF]

				H. Ko, W. Park, D.-J. Kim, M. Kobayashi, and Y. C. Sohn Biological activities of recombinant Manchurian trout FSH and LH: their receptor specificity, steroidogenic and vitellogenic potencies J. Mol. Endocrinol., January 1, 2007; 38(1): 99 - 111. [Abstract] [Full Text] [PDF]

				B. Campbell, J. Dickey, B. Beckman, G. Young, A. Pierce, H. Fukada, and P. Swanson Previtellogenic Oocyte Growth in Salmon: Relationships among Body Growth, Plasma Insulin-Like Growth Factor-1, Estradiol-17beta, Follicle-Stimulating Hormone and Expression of Ovarian Genes for Insulin-Like Growth Factors, Steroidogenic-Acute Regulatory Protein and Receptors for Gonadotropins, Growth Hormone, and Somatolactin Biol Reprod, July 1, 2006; 75(1): 34 - 44. [Abstract] [Full Text] [PDF]