TRANSFORMING GROWTH-FACTOR-BETA IN RAT-KIDNEY DURING COMPENSATORY RENAL GROWTH

Transforming growth factor-beta (TGF-beta) inhibits the DNA synthesis and stimulates the alkaline phosphatase activity of cultured renal cor tical tubular cells. When unilateral nephrectomy was performed, TGF-be ta activity content gradually decreased in the remaining kidney. An im munohistochemical study of the remaining kidney after uninephrectomy, however, showed that the expression of TGF-beta increased by the third day after uninephrectomy in the proximal tubular cells and an autorad iographic study revealed that TGF-beta expressing tubular cells were d ifferent from proliferating cells during compensatory renal growth. Th ese results indicate that the total renal TGF-beta content decreases a fter uninephrectomy, while the expression of TGF-beta in the proximal tubular cells may increase and act as a brake for compensatory renal h yperplasia.