Synthesis and secretion of proteins in vitro by isolated epithelial strips from the proximal and distal vas deferens of the rat.

Epithelial strips of rat vas deferens were isolated by a new technique and used to study differences in protein synthesis and secretion between morphologically defined segments of the vas deferens. The isolated strips were viable as judged by linear oxygen uptake over the incubation period and by preservation of structure. Epithelium from the proximal vas deferens incorporated more labelled amino acids into cytosolic (P less than 0.02) and incubation medium (P less than 0.01) proteins than did epithelium from distal vas deferens; this incorporation was inhibited by cycloheximide. Although some of the incubation medium proteins arose by leakage from damaged cells, specific protein secretion was indicated by differences in SDS-PAGE autoradiogram banding patterns and by differences in glycosylation between proteins in the incubation medium and those in the cytosol. Thus, the former contained more label from [14C]galactose incorporation than did cytosolic proteins (proximal: P less than 0.05; distal: P less than 0.005).