Glycogen metabolism of normal human myometrium and leiomyoma--possible hormonal control.

Glycogen concentration and the activities of enzymes of glycogen metabolism in myometrium of pre- and postmenopausal and pregnant women and in myomas were determined. Glycogen concentration in muscle from nonpregnant women was about 3 mg/g and rose to 13 mg/g in tissues obtained during cesarean sections. The activities of glycogen synthase phosphatase and phosphorylase were also markedly higher in myometrium of pregnant women. In 5 out of 8 myomas glycogen concentration and enzyme activities were similar to those found at the end of pregnancy. These observations suggest that glycogen metabolism of the myometrium is under the control of hormones and that the local hormonal environment of myomas may be different from that of the surrounding tissue.