Determination of sex hormone-binding globulin in human semen by selective ammonium sulphate precipitation.
A simple method was developed to measure the SHBG capacities of human serum, semen and sperm cells. After suitable dilution, disintegration and addition of labelled dihydrotestosterone-1,2-3 H or testosterone-1,2-3 H, the SHBG was precipitated by the addition of saturated ammonium sulphate in a final concentration of 42.3%. The precipitate was centrifuged and the activity of the non-bound, labelled steroid was counted in an aliquot of the supernatant. Subtraction of this result from the total activity yielded the SHBG-bound steroid in microgram/100 ml or nmol/l. Examination of 52 males gave normal values of means = 13.91 nmol/l (S.E.M. = 0,746) dihydrotestosterone binding globulin (DHTBG) and means = 11.67 nmol/l (S.E.M. = 0.555) testosterone binding globulin (TBG) in serum, while the concentrations in the seminal plasma were means = 10.89 nmol/l (S.E.M. = 0,723) DHTBG and means = 8.93 nmol/l (S.E.M. = 0.625) TBG. means = 5.57 ng/mg protein (S.E.M. = 0.516) DHTBG and means = 4.91 ng/mg protein (S.E.M. = 0.440) TBG were found in the disintegrated sperm cells.
D000645:Ammonium Sulfate; D000727:Androgen-Binding Protein / Q000032:analysis; D013196:Dihydrotestosterone / Q000378:metabolism; D006801:Humans; D008297:Male; D008722:Methods; D012661:Semen / Q000032:analysis*; D012738:Sex Hormone-Binding Globulin / Q000032:analysis*; D013094:Spermatozoa / Q000032:analysis; D013739:Testosterone / Q000378:metabolism
D000727:Androgen-Binding Protein; D012738:Sex Hormone-Binding Globulin; D013196:Dihydrotestosterone; D013739:Testosterone; D000645:Ammonium Sulfate