科研之友
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摘要
Testosterone (T) and its metabolites are important in the regulation of reproductive behavior in males of a variety of vertebrate species. Aromatase converts T to estradiol and 5 alpha-reductase converts T to 5 alpha-dihydrotestosterone (DHT). Male green anole reproduction depends on androgens, yet 5 alpha-reductase in the brain is not sexually dimorphic and does not vary with season. In contrast. aromatase activity in the male brain is increased during the breeding compared to non-breeding season, and males have higher levels than females during the breeding season. Aromatase is important for female, but not male, sexual behaviors. The present experiment was conducted to determine whether 5 alpha-reductase and aromatase are regulated by T. Enzyme activity was quantified in whole brain homogenates in both the breeding and non-breeding seasons in males and females that bad been treated with either a T or blank implant. In males only, T increased 5 alpha-reductase activity regardless of season and up-regulated aromatase during the breeding season specifically. Thus, regulation of both enzymes occurs in males, whereas females do not show parallel sensitivity to T. When considered with previous results, the data suggest that aromatase might influence a male function associated with the breeding season other than sexual behavior. 5 alpha-Reductase can be mediated by T availability, but this regulation may not serve a sex- or season-specific purpose.
- 出版日期2010-3-1
