MODULATION OF GLYCOPROTEIN-HORMONE-ALPHA-SUBUNIT AND GONADOTROPIN-II-BETA-SUBUNIT MESSENGER-RNA LEVELS IN THE PITUITARY-GLAND OF MATURE MALE AFRICAN CATFISH, CLARIAS-GARIEPINUS

The cDNAs encoding the glycoprotein hormone alpha-subunit (GP alpha) a nd the gonadotropin II beta-subunit (GTH II beta) were cloned from the pituitary gland of the African catfish, Clarias gariepinus. Using RNa se protection analysis, we studied the steady-state mRNA levels of GP alpha as well as GTH II beta in the pituitary gland of adult male catf ish. Castration of adult male catfish resulted in a significant decrea se of GTH II beta mRNA levels, whereas there was no change in the GP a lpha mRNA levels. Treatment of intact males with a single dose of 11-k etotestosterone (11-KT) resulted in dose-dependent increases in mRNA l evels of both GP alpha and GTH II beta. We conclude that 11-KT, a prom inent, non-aromatizable teleost androgen, has a stimulatory effect on the pituitary mRNA levels of GP alpha and GTH II beta of adult male fi sh.