Studies on pregnancy-associated globulin.

Using a radial immunodiffusion technique the serum levels of pregnancy-associated globulin (PAG) have been measured in eighteen females before and during administration of combined oestrogen/progestogen oral contraceptives, in twenty-eight females before and after the oestrogen or progestogen component of oral contraceptives and in ten males before and during stilboestrol therapy for prostatic carcinoma. Significant increases in PAG levels were observed during administration of (1) combined oestrogen/progestogen oral contraceptives, (2) the oestrogen component of the oral contraceptive and (3) stilboestrol. No change was observed after administration of the progestogen component. The serum PAG levels have also been determined in seventy-three patients with primary biliary cirrhosis, seventy-three hospital in-patients and forty-six patients with various malignant diseases. A marked increase in the percentage of PAG positive sera was observed in all disease groups, particularly in malignant disease. However, compared with late pregnancy, the serum levels in all three groups were low. Preliminary experiments have failed to show that this globulin possesses immunosuppressive properties.