β-Glucuronidase levels in patients with fibrocystic breast disease

Certain enzymes in tissues and body fluids may, through reversal of the detoxification process, influence the composition and availability of steroid hormones, toxins, and carcinogens. The ubiquitous enzyme β-glucuronidase, which hydrolyzes glucuronide conjugates, thereby reversing one of the main detoxification and excretion pathways, was found to vary in concentration in different cysts over a 300-fold range. The distribution was a continuum, devoid of discrete sub-populations. Evidence obtained on selected cyst fluids of high and low β-glucuronidase activities indicated that the level of the enzyme significantly influenced the ratio of unconjugated: glucuronidated estradiol. The patients with fibrocystic breast disease fell into 2 distinct subpopulations on the basis of their serum β-glucuronidase activity. In one group the activity was near normal, while in the second group the average serum β-glucuronidase activity was 3-fold higher than in the women who did not have benign breast disease.