Fish gonadotropin receptors: Molecular characterization and expression during gametogenesis

Abstract

In teleost fish, as in mammals, two types of gonadotropins (GTHs) —follicle stimulating hormone (FSH) and luteinizing hormone (LH)— play important roles in regulating gametogenesis. To comprehensively understand the molecular mechanism of endocrine regulation of fish gametogenesis, we cloned two types of GTH receptor (GTHR) cDNAs from three species of teleosts: amago salmon, tilapia and sunrise sculpin. The receptors were classified into two structurally related groups, homologous with mammalian receptors for FSH and LH (FSHR and LHR). The two types of receptors from amago salmon were reconstituted in COS-7 cells and functionally identified as FSHR and LHR. We examined changes in their mRNA levels during the course of gametogenesis. In general, the genes for both receptors showed similar expression profiles in males, with a peak at spermiation. In females, the FSHR gene was highly expressed during vitellogenesis, whereas the LHR gene showed a reverse pattern and was elevated only during final maturation. © 2002, The Japanese Society of Fisheries Science. All rights reserved.