Steroid hormone receptors in the female lower urinary tract

The preliminary results of a study to estimate the level of cytosol oestrogen and progesterone receptors in the lower urinary tract are presented. 29 full thickness biopsies were obtained from the vault, trigone and urethra of 9 female surgical patients aged 13-72 years. Cytosol assay for oestradiol-17 beta receptors and progesterone receptors was performed. Oestrogen receptors were present in all 5 urethral specimens examined and with a consistently higher concentration in the middle and distal thirds in comparison to the proximal urethra. In only 1 of the 9 vault specimens and 8 trigone specimens were receptors found and those in small quantities. No progesterone receptors were determined in any of the vault, trigone and urethral specimens examined. The presence of oestrogen receptors in the middle and distal thirds of the human female urethra is strong supportive evidence of the sensitivity of the urethra to oestrogens, and the higher concentration of those receptors in these sites in comparison to the proximal urethra, vault and trigone confirms the common embryological origin of the distal urethra and vagina from the definitive urogenital sinus. The absence of measurable progesterone receptors in all the lower urinary tract specimens examined is discussed.