ISSN:
1095-8649
Source:
Blackwell Publishing Journal Backfiles 1879-2005
Topics:
Biology
Notes:
Male and female Carassius auratus were exposed to safe (SC; 0.01 ppm) and sublethal (SL; 0·1 ppm) concentrations of an organochlorine pesticide γ-hexachlorocyclohexane (γ-HCH) for 4 weeks during the pre-spawning phase (June) of the annual reproductive cycle. Gonadosomatic index and gonadotropin levels were significantly lower after exposure to both γ-HCH concentrations than in control fish. After 4 weeks exposure, gonadal tissue from control, SC and SL exposed fish was incubated with carp hypophyseal homogenate (chh). The chh stimulated production of testosterone, 17,20β-dihydroxy-4-pregnen-3-one (17,20βP), 11-deoxycortisol, and 11-ketotesterone (11-KT) was estimated in the unconjugated (free) and conjugated (glucuronide) fractions by radioimmunoassay. In both sexes, testosterone production was greatly decreased in γ-HCH exposed fish compared to controls. 17,20βP production was low in all fish and was unaffected by γ-HCH. Free 11-deoxycortisol production by testicular fragments was higher in SL and SC compared with controls, while conjugated 11-deoxycortisol was increased only higher in the SL. In ovarian fragments from exposed fish, free 11-deoxycortisol decreased while glucuronide concentrations increased compared with controls. 11-KT production was significantly decreased in testicular fragments of exposed fish. The results indicate that γ-HCH inhibits gonadal recrudescence by decreasing both gonadotropin secretion and its potential for stimulation of steroidogenesis.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1111/j.1095-8649.1994.tb01198.x
