Prevention of bone mineral loss in postmenopausal women by norethisterone.

The effect of norethisterone on bone mineral metabolism was examined in 43 postmenopausal women. A significant decline in serum calcium, phosphate, and alkaline phosphatase in urinary calcium/creatinine ratio and in tubular maximum reabsorption of phosphate was demonstrated. There was no alteration in urinary hydroxyproline/creatinine ratio. The bone mineral content measured over two years by single photon absorptiometry was compared in 20 patients receiving norethisterone and a matched control group receiving placebo. There was significant protection against bone loss in the norethisterone group.