Abstract
Quantitative histochemical measurements of two enzymes of uridine diphosphoglucose (UDPG) metabolism have been made in the developing rat kidney nephron. Kidneys were examined from -4 days to 44 days of age. In the adult kidney, UDPG-pyrophosphatase was concentrated in proximal convoluted and straight tubules. During maturation, activity decreased in glomeruli, increased in the proximal tubule and changed little elsewhere in the nephron. UDPG-pyrophosphorylase revealed a different pattern. Activity was more nearly uniformly distributed throughout the nephron but was highest in the proximal straight tubule and ascending limb of Henle. During development, activity was unchanged or increased in glomeruli and small arteries and increased elsewhere, particularly in the proximal straight tubule and ascending limb of Henle.