|Budget Amount *help
¥3,300,000 (Direct Cost : ¥3,300,000)
Fiscal Year 1998 : ¥1,300,000 (Direct Cost : ¥1,300,000)
Fiscal Year 1997 : ¥2,000,000 (Direct Cost : ¥2,000,000)
In teleosts, it is considered that two types of GTH, GTH-I and GTH-II, are produced in the pituitary, and their molecules arc comprised of common alpha and distinct beta subunits. In order to understand regulation of gonadal development by two GTHs at molecular level, we examined gene expression of GTH-Ibeta and -IIbeta subunits, and then characterized GTH-Ibeta and -IIbeta genes in goldfish.
Seasonal changes. In females, pituitary mRNA levels of the GTH-Ibeta and -IIbeta increased synchronously in early spawning period, while in males, only GTH-IIbeta mRNA levels, but not GTH I beta, showed an increase. Effect of sex steroids. Testosterone and estradiol-17beta exerted an inhibitory effect on GTH-Ibeta gene expression but a stimulatory effect on GTH-IIbeta gene expression.
Characterization of the genes. Both genes consisted of three exons separated by two introns.
However, the pattern of the location of the putative regulatory elements was distinct between the 5-flanking regions of the GTH-Ibeta and -IIbeta genes.
Although the studies on GTH gene expressions are limited in teleosts, these studies indicate that the gene expressions of GTH-Ibeta and GTH-IIbeta are differentially regulated by sex steroids in goldfish, probably via upstream regulatory regions of the genes.