Serum sex-steroid binding protein in the fresh water teleost "Anguila criolla", Symbranchus marmoratus (Symbranchyformes)

CERIANI CAROLINA; CANOSA LUIS F; FRIDMAN OSVALDO

Revista de Ictiologia

Instituto de Ictiologia del NE

Año: 1994 vol. 2/3 p. 21 - 26

0327-6090

The properties of a sex-steroid binding protein (SBP) in the serum  of the anguila criolla Symbranchus marmoratus, were partially characterized. Anguila criolla SBP binds to estradiol-17b(E2) with limited capacity and moderated affinity. E2 is the most effective competitor for serum (3H)-E2 binding sites of all the steroids tested on female and male serum. At 50% displacement, the order in which the competitors displaced (3H)-E2 was E2  > Testosterone (T) > dehydroepiandrosterone (DHEA) > 5a-dihydrotestosterone (DHT). 17a-hydroiprogesterone (17a-HOP), deoxycorticosterone (DOC), corticosterone (CORT), and progesterone (P) did not reach 50% displacement, even at maximal concentrations. DOC only displaced 50% the bound (3H)-E2 in serum from male anguila criolla. No sex difference in either the association constant or the binding capacity was observed. The Scatchard plot was non-linear, an indicative of at least two binding sites.