Testicular androgen-binding protein (ABP): comparison of abp in rabbit testis and epididymis with a similar androgen-binding protein (TeBG) in rabbit serum

Androgen binding proteins of testis, epididymis, and plasma in man and monkey.

“…Previous analysis by PAGE2 recognized only a single binding protein component in the testis of nonprimates, indistinguishable from TeBG (4,7,25). In contrast, using PAGE at a pH of 7.8, 0WC, and a wide range of gel concentrations, we were able to recognize, in both monkey and human, multiple species of DHT-binding proteins (which appear related to each other as size and charge isomers) but only one species of human and monkey TeBG.…”

“…These properties also characterize a plasma ABP, testosterone-estradiol-binding globulin (TeBG), that does not occur in the rat but does occur in most other speices, including man (6). When rat ABP and human TeBG (4) or rabbit ABP and rabbit TeBG (7) have been compared, marked similarity has been noted.…”

Age Related Effects on Androgen Binding Protein (ABP) in Sheep Testis and Epididymis1

“…This protein binds 5n-DHT with high affinity (Ka= 0.18 x 109 M -I ) , has a molecular weight of about 70 000 daltons and an electrophoretic mobility of 0.52-0.56 on PAGE. It seems to be similar to that described in the rat (Ritztn et al 1971(Ritztn et al , 1973Hansson et al 1974) and in the rabbit (Danzo et al 1973(Danzo et al , 1974Hansson-et al 1975b). Our results also confirmed the presence of ABP in the ram as observed in the rete testis fluid and in epididymal and seminal plasma (Jegou et al 1976(Jegou et al , 1977(Jegou et al , 1978a.…”

Androgen Binding Proteins and Androgen Levels in the Human Testis and Epididymis

“…The present data therefore support the existence of two classes of androgen binding proteins in the human testis and epididymis, one with properties similar to intracellular androgen receptors and the other with properties reminiscent of serum TeBG and the androgen binding protein (ABP) found in the reproductive tract of other species including rat (Hansson et al 1973), rabbit, ram and bull (Hansson et al 1975a). Since ABP and TeBG within the same species (e. g. rabbit) have identical physio-chemical (Hansson et al 1975b) and immunological properties (Weddington et al 1975), it was important to ascertain to what extent contamination of the human testicular homogenate with serum TeBG was contributing to the observed androgen binding. The high correlation between the levels of CBG (an exclusive blood protein) and androgen binding implies that much of the binding can be explained by blood contamination.…”