To evaluate the influence of hypertension on human glomerulonephritis, 200 biopsies from 74 patients with Iga nephropathy were examined. Chosen for this study were 28 hypertensive patients and 46 normotensive subjects during an observation period of 3.84 +/- 2.17 years, which extended from the first to the last biopsy. In a comprehensive analysis, the following findings were observed: Glomerular sclerosis was analyzed semiquantitatively and estimated as "glomerular index" (GI). Interstitial volume (IV) was determined by the point-counting method. Mesangial electron dense deposits (MDD) and arteriolar hyaline change (HC) were also analyzed semiquantitatively. Arterial fibroelastic intimal thickening was analyzed morphometrically and estimated as the luminal "occlusive rate" (OR). These morphological parameters including their serial changes were compared between the hypertensives and the normotensives. The serial changes in GI and IV from the first to the last biopsy were significantly greater in the hypertensives than in the normotensives. Both OR and HC, including their serial changes, were significantly higher in the hypertensive subjects. In the study of MDD and its serial changes, no difference was apparent between the two groups. In the study of OR and HC, there was no correlation observed with GI. Our observations show that hypertension accelerates the progression of both glomerular and vascular sclerosis in case of human glomerulonephritis and suggests that this acceleration cannot only be explained by ischemia-related factors resulting from vascular sclerosis.