Dehydroepiandrosterone sulfate in plasma: hydrolysis, extraction and radioimmunoassay

At pH 4.5, the hydrolysis of 3 β-hydroxy-5-androsten-17-one 3-sulfate (DHA-SO 4) to DHA was complete within 75 min at 120° or 4h at 100°. In the same conditions, the 3 α-SO 4 of androsterone was stable, and only 8.5% of the 3 α-SO 4 of epiandrosterone hydrolysed to epiandrosterone. Of the sulfates of 5-androstene-3 β,17 β-diol, 100% of the 3 β-mono-SO 4, 2% of the 17 β-mono-SO 4 and none of the 3 β,17 β-di-SO 4 was converted to 5-androstenediol. Denatured plasma proteins adsorbed DHA. The recovery of DHA from plasma diluted 1:100 before hydrolysis was 91.0 ± 3.5% and from plasma diluted 1:10, 58.7 ± 6.2% (mean ± S.D.). In similar conditions the recovery of cholesterol from plasma diluted 1:20, was 0.12 − 1.76% (mean, 0.44%). A radioimmunoassay for DHA in extracts of hydrolysed plasma is described. Results for normal subjects in the age range 17–45y were 192 ± 73 μg/dl (22 men) and 158 ± 57 μg/dl (40 women).