Gene expression, localization, and pharmacological characterization of endothelin receptors in diabetic rat bladder dome

As there are significant amounts of functional endothelin receptors in the mammalian urinary tract, we examined the effect of experimental diabetes on the expression of endothelin receptors and their mRNAs in the rat bladder dome. The density of endothelin receptors in the rat bladder dome was highe r (8 and 16 weeks following the onset of diabetes) than in age-matched cont rols. insulin treatment, started 8 weeks after the induction of diabetes, p artially reversed the endothelin receptor alterations. The pharmacological profile of the endothelin receptors in the bladder dome was similar in all groups and was consistent with the predominance of the endothelin ETA recep tor subtype (ETA:ETB = approximately 4:1). Autoradiographic studies demonst rated that the endothelin receptors were located in all tissue components o f the bladder, including epithelial and muscular layers. Semiquantitative r everse transcription-polymerase chain reaction (RT-PCR) data indicated that diabetes increased the expression level of gene transcripts for both endot helin receptor subtypes and that insulin treatment reversed the mRNA upregu lation. (C) 2000 Elsevier Science B.V. All rights reserved.