Urinary glycosaminoglycan excretion during the menstrual cycle in normal young women.

PURPOSE We investigated whether the menstrual cycle affects urinary glycosaminoglycan (GAG) excretion in normal young women. MATERIALS AND METHODS Urine samples from 10 healthy women 19 to 21 years old were collected daily during the whole menstrual cycle. Concentration of total urinary GAG was assessed as mug hexuronic acid per mg creatinine. Proportions of sulfated GAG species were determined by agarose gel electrophoresis. RESULTS Mean excretion values +/- SD for period days 4 to 13 and 15 to 28 of the cycle were significantly different (0.445 +/- 0.041 vs 0.356 +/- 0.035 microg/mg, p <0.001). Correlation between values for the first and second halves of the cycle showed that this difference was consistent irrespective of individual variations in GAG excretion (r = 0.9757, p <0.001). Proportions of urinary sulfated GAG did not change during the cycle. CONCLUSIONS Excretion of total urinary GAG during the normal menstrual cycle of young women has a biphasic pattern with significantly higher values occurring in the first half of the cycle. This variation implies modulation by estrogens and consequently it should be considered when comparing the GAG concentration in urine samples from women of childbearing age.