Luminal secretion of myo-inositol by the rat epididymis perfused in vitro

Abstract
A technique for perfusing the lumen of rat epididymal tubules maintained in vitro showed that [3H]inulin was largely excluded from the lumen of unravelled tubules from the cauda and tubules from the corpus if the connective tissue capsule was removed. The preparation transported [3H]inositol from the bath fluid for 3 h against a concentration gradient in both regions with activity rising (16-29% of bath fluid values) in the cauda and reaching a plateau (18%) in the corpus epididymidis. HPLC [high performance liquid chromatography] showed that radioactivity was solely associated with inositol and its movement to the lumen was reduced by raising inositol in the bath fluid from 50 .mu.M (plasma levels) to 10 mM, but not affected by reducing the glucose concentration in the bath fluid or introducing physiological concentrations of inositol (30 mM) into the lumen. Secretion into the caudal lumen of unlabeled inositol measured by GLC was maintained for 3 h at concentrations (300 .mu.M) greater than those in the bath fluid and was not reduced when glucose or inositol were removed from the bath. Glucose was only detectable in the lumen when it was present in the bathing medium, reaching 1% of this concentration. Radioactivity appeared in the epididymal lumen reaching a plateau (19% of bath fluid values) in the corpus and cauda when [3H]glucose was added to the bath fluid, but no radiolabeled inositol was found in the lumen. Apparently, epididymal tissue is a major source of secreted inositol.

This publication has 1 reference indexed in Scilit: