Androgen-Binding Proteins from Human Hyperplastic Prostate as Evaluated by Electrophoresis

Abstract

Until 1972 it was shown that the androgen action in the prostatic tissue was through receptor proteins. In 1975 the synthesis of methyltrienolone (MT) opened a new field in searching receptor proteins. This synthetic androgen discriminates between receptors and other proteins such as TeBG and albumin. The main purpose in this investigation was to obtain the electrophoretic patterns of human prostatic androgen-binding proteins and compare them with those of other tissues from male genital tract (e.g., testes and epididymis), using as a reference the already described pattern in blood serum. The experimentation was carried out with cytosol (105,000 g) and nuclear fractions from the homogenized tissue. Both fractions were incubated with the tritiated steroids and then treated with dextran-coated charcoal. Polyacrylamide gel electrophoresis (PAGE) was then performed at pH 8.3 with acrylamide (T) 7.7%. The prostatic cytosol incubated with ³H-dihydrolestosterone (³H-DHT) revealed radioactive areas with the following average electrophoretic mobilities relative to Bromophenol Blue (Rf): 0.195, 0.285, 0.815, 0.910. When cytosol was incubated with ³H-MT the pattern showed radioactive peaks with Rf 0.280, 0.570, and 0.969. The nuclear fraction bound ³H-DHT in 0.190, 0.455, 0.570, 0.660, and 1.055 and bound ³H-MT in Rf 1.01. We concluded from these results that the electrophoretic patterns in the prostate gland shared some radioactive areas resembling TeBG and albumin, although they present low binding capacity. The other peaks with different electrophoretic mobilities are in the process of further identification.

Key Words:

• Androgen-binding proteins
• Prostate
• Hyperplasia
• Electrophoretic patterns