Endocrine Relationships of Leukocyte Alkaline Phosphatase

Leukocyte alkaline phosphatase activity has been noted to be different in men and women. The mean leukocyte alkaline phosphatase activity for 74 normal men, aged 19 to 60 years, was 23 mg. of phosphorus per 10¹⁰ polvmorphonuclear leukocytes per hour. The corresponding mean value for 75 normal young women, age 19-48 years, was 35 (p < .001). No significant differences between boys and girls occurred until the time of puberty. After the menopause, the values for women approached the values for men. Women treated with androgens had lower leukocyte alkaline phosphatase activity than did control women. These results suggest that androgenic hormones inhibit this enzyme, and that other, as yet undefined endocrine influences, also affect its level of activity.

In vitro tests with various concentrations of androgens and estrogens failed to provide conclusive evidence of direct effect on leukocytes although some degree of direct inhibition by androgens was suggested. Studies using saponin to effect enzyme release from leukocyte granules did not demonstrate whether the differences between men and women are differences of enzyme release or of content of leukocyte alkaline phosphatase.