Rats were injected with various amounts of bovine albumin (0.5,1.0 and 1.75 g/24 h), inducing thereby proteinuria ranging from 100 to 400 mg/24 h. The glomerular oxygen uptake, dry weight and glucose-6-phosphate dehydrogenase (G-6-PDH) activity were measured on the 4th day of proteinuria and in a group of control animals. Oxygen uptake increased of +60%, expressed per glomerulus and of +25% when expressed per milligram dry weight and this increase was not different between the 3 groups of rats. Glomerular dry weight increased significantly in the 3 series. There was an highly significant relationship between glomerular dry weight and oxygen uptake, combining the 3 series together. G-6-PDH increased as expected from previous experiments and this increase was more marked for the more marked proteinuria. The relationship between G-6-PDH and QO<sub>2</sub> was of borderline statistical significance (p = 0.05). The glomerular hypertrophy, oxidative hyperactivity and increase in G-6-PDH activity are probably related to transcellular transport of protein.