Effects of aromatizable and nonaromatizable androgens on the sex inversion of red-spotted grouper Epinephelus akaaraReport as inadecuate




Effects of aromatizable and nonaromatizable androgens on the sex inversion of red-spotted grouper Epinephelus akaara - Download this document for free, or read online. Document in PDF available to download.

Fish Physiology and Biochemistry

, 32:25

Received: 12 April 2005Accepted: 04 December 2005

Abstract

The effects of aromatizable 17α-methyltestosterone MT and non-aromatizable 17α-methyldihydrotestosterone MDHT on sex inversion in red-spotted grouper, Epinephelus akaara, were investigated. Fish were implanted with MT, MDHT and MT+AI aromatase inhibitor, AI respectively for one month. The results showed that the three treated groups turned into transitional stage with intersex gonads, which contained atretic oocytes and spermatogenic germ cells at all stages of spermatogenesis. The controls did not change sex. The gonads of more than half MT-implanted fish were in early transitional stages of sex inversion, whereas those of more than half MDHT and MT+AI-implanted fish were in late transitional stages of sex inversion. No difference in serum estradiol-17β E2 levels between the controls and the treated groups were observed, whereas 11-ketotestosterone 11-KT and testosterone T levels increased in all treated groups. Significantly lower gonadosomatic index GSI and gonadal aromatase activity were observed in the treated groups, which were in accordance with the lower mRNA expression of P450aromA. However, P450aromB mRNA expression increased in the MT group, while it did not change in the MDHT group. These results suggest that the sex inversion of red-spotted grouper by MT and MDHT implantation might be due to the suppression of P450aromA gene expression, and resulting in both the decrease of the ovarian estrogen –secretion, as well as the increase in the 11-KT levels. Furthermore, the main reason for MT being less effective than MDHT might be due to partial aromatization of MT to estrogen.

Keywordsaromatase inhibitor Epinephelus akaara methyltestosterone methyldihydrotestosterone sex inversion sex steroids  Download fulltext PDF



Author: Guang-Li Li - Xiao-Chun Liu - Hao-Ran Lin

Source: https://link.springer.com/



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