Activity of phosphatases and cellular contents in glomeruli and tubules isolated from growing rat renal cortex.

The activity of acid and alkaline phosphatases was determined in glomeruli and tubules isolated from 14-day old to adult rat renal cortex. Within a nephron fraction, each phosphatase activity produced a specific pattern which was not similar to that in other fractions. In the glomeruli the acid phosphatase activity increased between 14 and 21 days of life and was always higher than in the tubules where it did not significantly change with age. By using tartrate sodium and formaldehyde it was shown that the acid phosphatase isoenzymes are distributed according to a specific pattern which does not change during maturation. The alkaline phosphatase activity in glomeruli and in tubules increases with age but is always lower in the former fraction than in the latter. Furthermore, in young as well as in adult rats, glomeruli were characterized by a higher DNA content and lower RNA and protein/DNA ratios than the corresponding tubular fragments.