Accumulation of glycoprotein gonadotropin in the pituitary of juvenile rainbow trout in response to androgens and C21-steroids, including 11-steroids

Abstract

Effects of steroids on the accumulation of glycoprotein gonadotropin (GTH) in pituitaries of juvenile trout were investigated by means of scanning cytophotometry applied to immunocytochemical preparations, and with the use of a radioimmunoassay. Effects on other aspects of GTH-cell activity were analyzed by measuring the size of the gonadotrops and their nuclei. Progesterone added to aquarium water and methyltestosterone incorporated into the food showed a pronounced stimulatory effect on the accumulation of GTH. To a lesser extent, treatment with cortisol, cortisone, and desoxycorticosterone acetate administered to aquarium water, and 11 beta-hydroxy-androstenedione added to the food resulted in an increase of the hypophysial content of GTH. Steroids stimulating the accumulation of GTH in the pituitary also exhibited a positive effect on GTH-cell activity as indicated by an increase in the size of gonadotropic cells. Progesterone incorporated into the food did not influence the GTH-content and the GTH-cell activity. It is suggested that the route of administration of an exogenous steroid is essential for its effect on GTH cells in trout. Comparison of GTH values reveals an excellent correlation between the data from the radioimmunoassay and those from the corresponding densitometric measurements. No correlation was observed between values of morphometrically determined GTH-cell activity and the densitometric values reflecting hypophysial GTH content.

Pubertal development of male African catfish,Clarias gariepinus. In vitro steroidogenesis by testis and interrenal tissue and plasma levels of sexual steroids

“…Thus, an effect of andrggens of interrenal origin on the maturation of the BPG axis is unlikely. However, it cannot be excluded that cortisol has a weak stimulatory (van den Hurk et al 1984;Dufour et al 1983) or inhibitory effect (van den Hurk and van Oordt 1985) on the BPG axis in juvenile fish. In addition, these data suggest that interrenal androgen production may be a characteristic of adult male catfish.…”

Steroidogenesis in pre- and postspawned ovaries of feral African catfish, Clarias gariepinus

“…Thus it seems that the high postvitellogenic level of testosterone results from a reduced aromatase activity in the ovaries. The androgen might be involved in GTH synthesis and storage prior to the prespawning GTH surge (Peter and Crim, 19'79;Gielen and Goos, 1983;Kagawa et al, 1983;Van Den Hurk et al, 1984;De Leeuw et al, 1986).…”

Effects of Castration and Androgen‐treatment on Pituitary and Testes of the Three‐spined Stickleback, Gasterosteus aculeatus L., in the Breeding Season

“…The suppressive effect of MT on stickleback GTH cells in the breeding season, found in the present study, is in marked contrast to the stimulation of GTH-cells (increase of GER dilations) after MT treatment in short photoperiod in winter (Borg et al 1984). In juvenile salmonids (Crim and Evans 1979, Gielen et al 1982, van den Hurk 1982. van den Hurk et al 1984 and the silver eel (Olivereau and Olivereau 1979), steroid treatments caused a dramatic increase in pituitary GTH content.…”