Secretory piece and plasma proteins in human cervical mucus during the cycle

Proteins of human cervical mucus were quantified on polyacrylamide gels and their concentrations relative to the mucous glycoprotein were calculated. In contrast with the cyclic variation to be expected in the ratio between albumin and the mucous glycoprotein, we found a constant ratio between IgA-related secretory piece and mucous glycoprotein. Secretory piece appeared to be an important protein in the mucus with respect to its concentration. No significant differences in the amount of mucus, its cyclic variation, protein concentration and composition could be found when normal mucus was compared from women sterilized by tubal ligation.