A sequential radioimmunoassay procedure for unconjugated and conjugated estrone, estradiol-17 beta and estriol in male human plasma was developed. The blank values in this assay for unconjugated estrone, estradiol-17 beta, estriol conjugated estrone, estradiol-17 beta and conjugated estriol were 0.36 +/- 1.14 pg, 3.90 +/- 2.75 pg, 2.25 +/- 2.08 pg, 0.92 +/- 1.51 pg, 5.02 +/- 2.86 pg and 3.12 +/- 2.97 pg, respectively. Mean values of unconjugated estrone, estradiol-17 beta, estriol, conjugated estrone, estradiol-17 beta and conjugated estriol in plasma from 28 normal adult males were 38.4 +/- 13.4 pg/ml, 32.6 +/- 9.90 pg/ml, 4.06 +/- 3.68 pg/ml, 34.2 +/- 13.8 pg/ml, 40.4 +/- 12.3 pg/ml and 31.8 +/- 7.41 pg/ml, respectively. Both unconjugated and conjugated estrogen levels in patients with liver cirrhosis were elevated and conjugated estrogen, especially estriol levels, in patients with renal insufficiency were markedly elevated.</p