Diabetes influences the effect of 17 beta-estradiol on mechanical responses of rat urethra and detrusor strips

Estrogen deficiency is one of the factors involved in the stress incontinen ce in postmenopausal women, and estrogens have been used clinically in the treatment of urinary disorders during menopause. Sex hormones seem to be al so involved in the diabetic changes of urinary bladder and urethra, because ovariectomy causes an increase in the micturition of streptozotocin-diabet ic rats. In the present study diabetic and healthy female rats were used to investigate the effect of 17 beta-estradiol on mechanical contractions to norepinephrine and to KCl and relaxations to ATP on isolated proximal ureth ral preparations as well as on contractions to: ACh, ATP and KCl on detruso r smooth muscle strips. The data were compared with those obtained in OVX a nimals, with or without estradiol replacement. The present study showed tha t ovariectomy decreased the responses to ATP, NE and:KCl in urethral prepar ations, and responses to ATP, ACh and KCl in bladder strips from both healt hy and diabetic rats. Diabetes appeared to potentiate the effect of ovariec tomy in both tissues. Estrogen replacement was able to recover functional r esponses in urethras of healthy rats. In diabetic rats, this treatment part ially restored ATP-induced responses in both tissues, almost completely res tored those to NE in urethra and those to ACh in bladder. This study clearl y indicated that abnormalities of urethra and bladder function caused by ov ariectomy can be restored by estrogen treatment also in diabetic animals, a t least at an early stage of disease.