Publication Abstract

Plasma growth hormone levels during sexual maturation in diploid and triploid rainbow trout, Oncorhychus mykiss

J.P.Sumpter, R.F. Lincoln, V.J. Bye, J.F. Carragher and P.Y. le Bail

Plasma growth hormone concentrations were determined in diploid and triploid rainbow trout (Oncorhynchus mykiss) of both sexes during sexual maturation. Diploid females grow large ovaries, whereas triploid female trout show no ovarian development. The results suggest that the elevated growth hormone concentration in mature male trout was a consequence not of reproduction per se, but of the loss of condition that accompanied spawning. This hypothesis was supported by the results from the females. These results suggest that it was the nutritional insufficiency accompanying reproduction in male fish that caused the elevation in growth hormone concentration.

Reference:

J.P.Sumpter, R.F. Lincoln, V.J. Bye, J.F. Carragher and P.Y. le Bail, 1991. Plasma growth hormone levels during sexual maturation in diploid and triploid rainbow trout, Oncorhychus mykiss. General and Comparative Endocrinology, 83: 103-110.