CYTOGENETIC ANIMAL

Author: ZAPATERO CABALLERO HELENA.
Year: 2003.
University: COMPLUTENSE DE MADRID.
Place of defense: FACULTAD DE CIENCIAS BIOLÓGICAS.
Place of preparation: HOSPITAL CARLOS III. MADRID.

Summary: The proper expression of GnRH receptor gene (R-GnRH) in the cells gonadotropas pituitary signaling is critical for GnRH and thus for the release of gonadotropins and sexual development. In this paper we studied the ontogeny of the expression of gene R-GnRH during puberal development of Wistar rats (male and female) as well as the changes that occur in aging (male). In addition, we studied the expression pituitary of R-GnRH a model described as hipogonadal: obese Zucker rats. We have demonstrated that the expression of gene R-GnRH in Wistar male rats increases progesivamente from day 5 postnatal until day 25, with an acceleration to achieve maximum day 35, onset of puberty in males. The expression of beta subunits of gonadotropins follows a pattern similar to the receptor but delayed temporarily. Furthermore, we demonstrated the existence of a clear sexual dimorphism, as the data ontogeny gene expression of R-GnRH in female rats shows a peak early in the 20 days, with subsequent decline, also supported by the expression of subnidades beta gonadotropins. In both cases, the expression of the alpha subunit, which is common to LH and FSH, presents a distinct pattern of expression, suggesting its regulation by various other signs of GnRH. Cetrorelix, GnRH antagonist, completely abolishes the expression of genes involved in the development puberal, R-GnRH, Lhbeta and FSHbeta in both sexes. This demonstrates that his expression depends on hypothalamic GnRH. However, it modifies the expression of the alpha subunit, which reaffirms its independent regulation of GnRH. We have shown a decline in levels of mRNA R-GnRH in aging that can contribute to hypogonadotropic hypogonadism from this period. We have also studied the expression of the gene R-GnRH in rats hipogonadal Zucker, with many metabolic disorders, and we have seen that the changes are not significant in rats have, except for an increase in LH reflecting a possible ovarian resistance to its action . In males, surprisingly their phenotype hipogonadal is accompanied by a sharp increase in the expression of genes of gonadotropo, that this increase will translate into greater functionality shaft.