Bidder's organ and aromatase activity in the male toad Bufo arenarum.

SCAIA MARIA FLORENCIA; REGUEIRA ELEONORA; CEBALLOS NORA RAQUEL

Carlos Paz, Cordoba

Congreso; XLIV Reunion Anual de la Sociedad Argentina de Investigacion Bioquimica y Biologia Molecular.; 2008

SAIB

The Bidder´s organ (BO) is a rudimentary ovary located at the anterior end of the testis in male true toads (Bufonidae), its development being arrested by the presence of functional testes. Since Bufo arenarum testes lack aromatase activity (ARO), it has been suggested that BO could be the source of circulating estradiol (E2). The main goal of this work is to determine the expression of ARO and other steroidogenic enzymes in BO as well as the correlation between glucocorticoids (GC), androgens and the development of BO. The expression of the cytochrome P450 SCC and 3beta-hydroxysteroid dehydrogenase/isomerase was detected by immunocytochemistry and substrate conversion, respectively. Moreover, ARO activity was detected by the conversion of testosterone (T) into E2 and by Westernblot analysis. These results indicate BO has the capacity to synthesize estrogens from cholesterol. In addition, specific activity of ARO, expressed as nmole per mg protein, increased with organ development. The presence and weight of BO positively correlates with T concentration but no correlation between those parameters and GC was found. Finally, the presence of ARO activity in BO encouraged us to study this enzyme in other peripheric organs. Results indicate that ARO activity is also present in liver but not in fat bodies, suggesting that the liver could contribute to the overall production of E2.