Abstract: 13

EFFECTS OF HORMONES, SEX-REVERSAL, & COMPLETE OR PARTIAL GONADECTOMY ON REGENERATION OF ABLATED GONADS IN RAINBOW TROUT.

C A Kersten^{1 *}, M Krisfalusi^{1 *}, J E Parsons² , J G Cloud^{1 *}
Department of Biological Sciences, University of Idaho, Moscow, Idaho ¹
Troutlodge, Sumner, Washington ²

Sexual plasticity in fishes has been demonstrated by the ability to sex-reverse these organisms during early embryology. Gonadal regeneration following surgical ablation has been reported in several species. In mature goldfish, regeneration of testes and ovotestes has been observed following ovariectomy and administration of 11-ketotestosterone. The objectives of this investigation were to identify the conditions for and the controls of gonadal regeneration in rainbow trout (RBT). Two groups of RBT were bilaterally gonadectomized (Gx). In experiment 1, masculinized females were either completely or incompletely Gx. In experiment 2, male and female RBT were either Gx or left intact and given estradiol or testosterone implants. In experiment 1, only those fish with a gonadal remnant following surgery regenerated their gonads (0.01>p>0.005). In all cases, masculinized females regenerated testicular tissue. In experiment 2, Gx males regenerated testicular tissue and females regenerated ovarian tissue regardless of the administered hormone. Intact fish were not sex-reversed as a result of hormone administration. Taken together, these results indicate that a gonadal remnant is necessary for regeneration, that regeneration in sex-reversed fish is dependent upon its phenotype, and that the sex of a regenerating gonad is not reversed with the levels of estradiol or testosterone used in this study.

    This abstract is being presented on Sunday, August 1 at 8:00 AM to 10:15 AM at CUB 2nd Floor Ballroom.