Ethinylestradiol (EE, 17a-ethynyl-l,3,5(lO)-estratriene-3,l'IP-diol) 30 pg daily, in combination with 150 pg per day of desogestrel (Org 2969, 17a-ethynyl-18-methyl-l lmethylene-4-estrene-17P-01) or levonorgestrel (17~-ethynyl-18-methyl-4-estrene-17P-ol-3-one), was administered to two groups of 10 healthy human women who had been without hormonal treatment during 3 months prior to the study. The preparations were given for three 21-day cycles with 7-day intervals. Blood samples were taken before treatment and at the end of the third treatment period. Serum sex-hormone binding globulin (SHBG), ceruloplasmin, ornsomucoid, Cl-esterase inhibitor and C4 were analyzed by electroimmunoassay and transcortin was assayed as cortisol-binding capacity. Serum testosterone was assayed by radioimmunoassay of methylenedichloride extracts using an antiserum with about 20% cross-reactivity for dihydrotestosterone (DHT).The increases in serum ceruloplasmin and transcortin concentrations were the same in both groups (about 80% and 100-140%, respectively), whereas no significant change was noted for the orosomucoid, C1-esterase inhibitor or C4 concentrations. The SHBG concentration, how-Res Commun 72:489, 1976.