Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0042755 (masculinization)
 2,562 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The period of maximal feminizing action of 17beta-estradiol (E(2)) upon sex ratio is before 10 days posthatching in tilapia (Oreochromis mossambicus). The effect of E(2) at this time is mimicked by para-chlorophenylalanine (p-CPA), a serotonin (5-hydroxytryptamine; 5-HT) synthesis inhibitor. The effect of E(2) on sexual differentiation may be mediated by the 5-HT system, which is consistent with the suggestion in mammals. The masculinizing actions of 17alpha-methyltestosterone (MT) are most potent later at up to day 20 of age, and may depend on MT induction of aromatase activity. In the present study, the effects of gonadal steroids and p-CPA on brain aromatase and estrogen receptor (ER) mRNA expression during the critical period of sexual differentiation were investigated. Treatment of tilapia with E(2) resulted in a significant decrease in the expression of brain aromatase and ERalpha between days 0 and 10, but not subsequently. The effect of E(2) at this time can be mimicked by p-CPA. Treatment of tilapia with MT, by contrast, resulted in a significant increase in brain aromatase, ERalpha and ERbeta mRNA expression when given between days 10 and 20. The downregulation of brain aromatase and ERalpha mRNA expression by E(2) before 10 days of age and, in turn, the upregulation of brain aromatase and ERalpha and ERbeta mRNA expression by MT at up to day 20 of age coincide with the period in which E(2) and MT have the maximal effect on gonadal feminization and masculinization, respectively.
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PMID:Estradiol and para-chlorophenylalanine downregulate the expression of brain aromatase and estrogen receptor-alpha mRNA during the critical period of feminization in tilapia (Oreochromis mossambicus). 1169 64

cDNA sequences of serotonin (5-hydroxytryptamine, 5-HT) 1A and 1D receptors were cloned from the tilapia, Oreochromis mossambicus, brain. The influence of both gonadal steroids and temperature on the ontogenetic expression of brain 5-HT1A and 5-HT1D receptors from days 5 to 15 post-hatch, a critical period of sexual differentiation, was investigated using quantitative real-time reverse transcription-polymerase chain reaction. Neither estrogen nor methyltestosterone had an effect on the ontogenetic expression of 5-HT1A or 5-HT1D receptors. Between days 5 and 10 post-hatch, a critical period for low-temperature-induced feminization, we found no significant difference in the ontogenetic expression of 5-HT1A between exposure to low and elevated temperature. A similar result was found for 5-HT1D. Between days 10 and 15 post-hatch, a critical period for elevated-temperature-induced masculinization, the ontogenetic expression of neither brain 5-HT1A nor 5-HT1D was altered by exposure to elevated temperature. These results suggest that neither brain 5-HT1A nor 5-HT1D plays a critical role in either gonadal steroid- or temperature-induced sexual differentiation.
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PMID:Influence of temperature and gonadal steroids on the ontogenetic expression of brain serotonin 1A and 1D receptors during the critical period of sexual differentiation in tilapia, Oreochromis mossambicus. 1635 46