부산대학교 도서관

Homozygous carriers (BB) of the Booroola fecundity gene FecBare characterized by high plasma concentrations of immunoreactive or biologically active FSH and, to a lesser extent, of immunoreactive LH, relative to non-carriers (++). Bovine cDNA probes for the α gonadotrophin, FSHβand LHβgenes were used to investigate FecB-specific differences in the mRNA species for the gonadotrophin subunits in pituitaries obtained from ++ and BB mid-luteal phase ovary-intact ewes, ovariectomized ewes and ovary-intact or ovariectomized ewes with hypothalamic–pituitary disconnection (HPD) given the same regimen of pulsatile GnRH. No FecB-specific differences in the number or size of mRNA transcripts detected by northern blotting were noted for any of these genes. Densitometry of the northern blots revealed no significant FecB-specific differences in the relative amounts of mRNA encoding α gonadotrophin, FSHβ or LHβ in the pituitaries from any of the experimental groups of ++ and BB sheep. Furthermore, there were no significant FecB-specific differences in the pituitary content of FSH or LH in these animals, despite significantly higher plasma concentrations of FSH in the ovary-intact and ovariectomized HPD groups. These data show that whereas the FecBgene causes increased plasma concentrations of FSH, no consistent effects can be demonstrated on pituitary gonadotrophin content or on gonadotrophin subunit gene transcription, using northern analysis. We suggest that the increased FSH secretion observed in FecB-carriers does not arise from an effect of the FecBgene on the size or stability of the gonadotrophin subunit mRNA, but is more likely to arise from differences in post-translational modification or secretion of the FSH protein in FecB-carriers.