In membranous nephropathy (MN) overproduction of matrix by glomerular epithelial cells (GEC) is believed to be responsible for glomerular basement in membrane thickening and spikes. We studied experimental MN in rats (passive Heymann nephritis, PHN) at 5, 10 and 30 days. PHN rats exhibited a marked increase GEC immunostaining for TGF-β2 at all time points. TGF-β3 staining was increased at day 10 only, and TGF-β1 was unchanged. Glomerular mRNA for TGF-β2 and -β3 was increased by day 5 when urine protein increased, whereas TGF-β1 was not. TGF-β2 bioactivity was increased at day 5. There was also a marked increase in GEC immunostaining for TGF-β receptor type I (TβIR) and TGF-β receptor type II (TβII) at all time points in PHN. mRNA levels for both receptors increased at day 5. Increases in protein expression and mRNA levels for the TGF-β2 and -β3 isoforms, and TβIR and TβRII were prevented by complement depletion. We conclude that complement- mediated injury to the GEC in vivo is associated with the up-regulation of TGF-β2 and -β3 isoforms, an increase in TGF-β2 bioactivity, and an increase in TβR1 and TβRII expression. This contrasts with changes in TGF- β1 reported in mesangial disease, suggesting that TGF-β2 and β-3 may be important in diseases of the GEC. The differential expression of TGF-β isoforms and receptors may be important determinants of the GEC response to injury.