Estrogens and the urogenital tract. Studies on steroid hormone receptors and a clinical study on a new estradiol-releasing vaginal ring.

Estrogen receptors and progesterone receptors were detected and quantified in female pelvic floor muscles, urogenital ligaments and in uterus (myometrium) by use of monoclonal antibody assay techniques. Qualitative assessment with immunohistochemical methods further localized the estrogen receptors and progesterone receptors to the nuclei of connective tissue cells and striated muscle cells in the levator ani muscle, and to the cell nuclei of smooth muscle cells in the round ligament. These findings fulfil a prerequisite for viewing the pelvic floor and the round ligament as target organs for estrogens. The results also contribute to the understanding of the etiological role the reduction in estrogen levels has on the increased incidence of prolapse and urinary incontinence after the menopause. For treatment of urogenital mucosal atrophy a new vaginal silicone ring releasing 5-10 micrograms estradiol/24 h for a minimum of 90 days has been developed. The efficacy, safety and acceptability of the ring were studied in 222 postmenopausal women with symptoms and signs of atrophic vaginal mucosa. The maturation of the vaginal epithelium, as measured by cytological parameters, was significantly improved during treatment. There were significant decreases in vaginal pH, and these changes correlated well with the cytological evaluation. No proliferation of the endometrium was encountered. The therapy had a significant effect on symptoms and on signs of atrophic vaginitis, with cure/improvement registered in > or = 90%. The patient acceptability was high. It is concluded that a vaginal silicone ring giving a continuous release of an ultra-low dose of estradiol is an effective and safe treatment for urogenital estrogen deficiency. No addition of progestogen is needed.