11ß-hydroxylase and androgen receptor mRNA expression in the ovary, testis and brain of the protogynous hermaphrodite Thalassoma duperrey
Morrey, C.E.; Nagahama, Y. (2000). 11ß-hydroxylase and androgen receptor mRNA expression in the ovary, testis and brain of the protogynous hermaphrodite Thalassoma duperrey, in: Norberg, B. et al. (Ed.) Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. pp. 157-159
In: Norberg, B. et al. (2000). Proceedings of the 6th International Symposium on the Reproductive Physiology of Fish, Bergen, Norway, July 4-9, 1999. International Symposium on the Reproductive Physiology of Fish, 6. Department of Fisheries and Marine Biology, University of Bergen: Bergen. ISBN 82-7461-048-2. 499 pp., more
In: International Symposium on the Reproductive Physiology of Fish. Museo Nacional de Ciencias Naturales. , more
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| Authors | | Top |
- Morrey, C.E.
- Nagahama, Y.
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| Abstract |
In Thalassoma duperrey, distinct changes in steroidogenic enzyme expression correlate with sex change. As the gonad redifferentiates from an ovary to a testis, expression of ovarian aromatase is down-regulated while 11 beta -hydroxylase (11 beta -OH) is up-regulated indicating the importance of the respective hormones, estradiol (E2) and 11-ketotestosterone (11-KT) to phenotypic sex. Whereas aromatase is absent in the testis, 11 beta -OH is present at substantial levels in the ovary suggesting a potential role in normal ovarian physiology as well as testicular differentiation. To determine whether the ovary can respond directly to 11-KT, we cloned and characterized the expression of an androgen receptor (AR) from T. duperrey. Specific RT-PCR for T. duperrey AR amplified a 403 bp product from Initial and Terminal Phase testes, brains and ovaries indicating the ovary may be directly responsive to 11-KT via the AR; however, the physiological function of 11-KT in the ovary remains unresolved. Up-regulation of AR mRNA expression at Stage 3/4 of sex change suggests an important role for 11-KT in initiating the proliferation of spermatogonia and spermatogenesis. Similarly, 11-KT is generally assumed to act in the brain to control male-specific behavior; therefore, we also characterized expression of AR and 11 beta -OH mRNA in the brain. RT-PCR analysis revealed AR mRNA expression is highest in TP male brains corresponding with male-typical behaviors. 11 beta -OH mRNA expression also appears to be highest in TP males, although it is widely distributed throughout the brain of both sexes. 11-KT has long been thought to act on the brain; however, the source of 11-KT was assumed to be gonadal. These results indicate conversion of T to 11-KT may actually occur within the brain. Consequently, mechanisms of 11-KT action in the brain may parallel the E2 mechanisms described for mammalian sexual behavior. The results of this study support a role of androgens in testicular function and male behavior as well as ovarian development in the protogynous wrasse T. duperrey. |
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