THE VARIATION OF NEUTROPHIL ALKALINE PHOSPHATASE DURING THE MENSTRUAL CYCLE

Summary

The variation of neutrophil alkaline phosphatase (N.A.P.) activity during the menstrual cycle was investigated in 9 normal females, 7 females taking various oral contraceptives, and an infertile female receiving gonadotrophin therapy. The day to day variation of N.A.P. values in 2 males and the range of values in 272 normal adults and 72 pregnant women were also determined. Adult females have a significantly higher N.A.P. value than males. Normal females show two physiological peaks of N.A.P. activity during the menstrual cycle, the first at ovulation, and a second in the luteal phase. The variation of N.A.P. in the menstrual cycle is probably related to fluctuating oestrogen levels. In most cases these peaks are not affected by oral contraceptive administration which is often associated with high enzyme levels as in pregnancy. The N.A.P. response varies with different oral contraceptives. The present study provides further evidence that combined oral contraceptive preparations do not always inhibit ovulation. Daily N.A.P. estimations should prove useful in the assessment of menstrual function, and the investigation of infertility.