Publication Abstract

Urine of reproductively mature female rainbow trout, Oncorhynchus mykiss (Walbaum), contains a priming pheromone which enhances plasma levels of sex steroids and gonadotrophin II in males

Urine of reproductively mature femalerainbow trout, Oncorhynchus mykiss (Walbaum), contains a priming pheromone whichenhances plasma levels of sex steroids and gonadotrophin II in males

A.P. Scott, N.R. Liley and E.L.M. Vermeirssen

Urine of reproductively mature female rainbow trout was shown to contain apriming pheromone which raised the levels of 17α,20β-dihydroxy-4-pregnen- 3-one (17,20β-P), testosterone and gonadotrophin II in the blood plasma ofreproductively mature male rainbow trout. Milt volumes however, were unaffected.

Because it had been established in a previous study thatthe sulphated form of 17,20β-P is abundant in the urine of spawning rainbow trout, synthetic 17a,20β-dihydroxy-4-pregnen-3-one20-sulphate was also tested for pheromonal activity. It was found to have only a small andinconsistent priming effect on steroid levels and did not alter the orientation orspawning activity of males.

It was also shown that, in the majority ofexperiments, there was a significant drop, over the course of 24 h, in the levels of 17,20βP and testosterone in thecontrol groups of males.

Reference:

A.P. Scott, N.R. Liley and E.L.M. Vermeirssen, 1994. Urine of reproductively mature femalerainbow trout, Oncorhynchus mykiss (Walbaum), contains a priming pheromone which enhancesplasma levels of sex steroids and gonadotrophin II in males. Journal of FishBiology, 44: 131-147.

 

A.P. Scott*, N.R. Liley and E.L.M. Vermeirssen*

Journal of Fish Biology, 44: 131-147