Rat peritubular cell secretory activity: modulation by vitamin A.

Protein synthesis and secretion by rat peritubular cells cultured in the presence or in the absence of vitamin A were analyzed after labelling the cells with different amino acids. Vitamin A reduces the amount of proline incorporated into the newly-synthesized proteins secreted by the peritubular cells. By mono- and two-dimensional gel electrophoresis analysis, qualitative differences induced by retinol addition were detected in the proteins secreted by the proline-labelled cells. In particular we demonstrate that the amount of fibronectin secreted by the cells is reduced after retinol addition. Northern blot analysis indicates that fibronectin messenger RNA transcription is also reduced as a consequence of the vitamin addition.