Unusually high concentrations of Zn alpha 2-glycoprotein and the lack of alpha 2HS-glycoprotein in human ejaculates.

Ejaculates of 132 nonvasectomized and 129 vasectomized men were assayed for their Zn alpha 2- and alpha 2HS-glycoprotein contents by radial immunodiffusion. The respective mean concentrations of Zn alpha 2-glycoprotein were 319 and 309 mg/L, respectively, but these fluids were devoid of alpha 2HS-glycoprotein. In comparison, the concentration of these two proteins in serum of normal men were 62 and 617 mg/L for Zn alpha 2- and alpha 2HS-glycoprotein, respectively. Because albumin in the ejaculates is 100-fold less concentrated than in serum, the fivefold increase in the concentration of Zn alpha 2-glycoprotein of the ejaculates represents about a 500-fold enrichment of this protein in the ejaculates over the concentration expected by comparison with albumin.