Although tubular pathological changes and functional derangements have been noted to occur in patients with acute glomerulonephritis, these have been overshadowed by the severer glomerular abnormalities. In the present study the aim was twofold: to evaluate progressive changes in tubular pathology and to attempt to correlate them with alterations in tubular function. Methods Patients with acute glomerulonephritis were biopsied as soon as the diagnosis was suspected. Biopsies were done as previously reported,1 with the patients lying prone and by means of the Turkel needle. Within a few days of the biopsy renal-function tests were done. These included the measurement of glomerular filtration rate by inulin clearance, effective renal plasma flow by sodium p-aminohippurate (PAH) clearance, and tubular function by TmPAH.2-4 Thereafter patients were followed clinically and by frequent urinalyses. At approximately one month after the first studies, repeat biopsies and function tests were performed. Whenever feasible these were again repeated