The role of sex hormone binding globulin (SHBG) in conversion of testosterone to 5 α-dihydrotestosterone and androstenedione in skin from suprapubic area of women. Part 1. In vitro study with skin sections

The influence of sex hormone binding globulin (SHBG) on testosterone metabolism into 5 alpha-dihydrotestosterone and androstenedione in skin sections from the suprapubic area women of reproductive age was investigated. The SHBG was obtained by precipitating plasma proteins of women in the third trimester of pregnancy with ammonium sulphate. Steroids were isolated from the incubation medium by extraction with acetone and reextraction with ether and purified using column chromatography on aluminum oxide, thin layer chromatography (TLC) on silica gel and following formation of acetyl derivatives the thin layer chromatography on silica gel was again carried out. Individual recovery of androstenedione was calculated using radioisotope and the recovery of 5 alpha-dihydrotestosterone was determined with gas chromatography. Mean value of identified 5 alpha-dihydrotestosterone in the presence of inactive globulin was 52.77 fg/mg, whereas following the addition of active globulin the value decreased to 19.62 fg/mg. Mean value of identified androstenedione in preparations with inactive globulin (62.97 fg/mg), in the presence of active globulin was also reduced to 18.15 fg/mg. (author)