ISSN:
1095-8649
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
The gonadosomatic index (GSI) of pre–pubertal male rainbow trout, which had been injected biweekly with partially purified salmon gonadotropin (sG–G100, 50 μ mUg kg−1 body weight), increased from 0.05 to 1.85 over 21 weeks from injection, while control GSI remained below 0.05. Plasma testosterone (T) increased from 2 to 11.34 ng ml−1 by week 21 in injected fish, while control level remained below 1.5 ng ml−1. In injected fish plasma 11–ketotestosterone (KT) and 17,20–dihydroxyprogesterone (17α20βP) levels increased from 20.2 to 41.9 and 8.9 to 219.7 ng ml−1 respectively. Plasma T, 11–KT, and 17α20βP were all correlated with the GSI (P〈0–001) in injected fish. The most advanced stage of germ cells present in the control fish were spermatogonia. However, in injected fish spermatozoa were present by week 21. Eggs fertilized at this time with spermatozoa from injected fish achieved a 78% fertilization rate, whereas the testicular homogenate was incapable of fertilizing eggs.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1095-8649.1994.tb01270.x
Permalink