35S-glycosaminoglycan and 35S-glycopeptide metabolism by diabetic glomeruli and aorta.

35S-glycosaminoglycan metabolism by glomeruli isolated from streptozotocin-diabetic and control rats was studied in vivo and in vitro. Total 35S-glycosaminoglycan synthesis and retention in the matrix by diabetic glomeruli was reduced while degradation was increased. 35S-glycosaminoglycan content of isolated GBM was similarly decreased. Whereas 35S-glycosaminoglycan content of glomeruli and GBM was decreased after in vitro incubation with 35SO4, a larger proportion of total 35S-glycosaminoglycans was found in the incubation medium from diabetic glomeruli. Both control and diabetic glomeruli synthesize 35S-labeled glycopeptides, the quantity from diabetic glomeruli being reduced. Aorta from 35SO4-injected diabetic rats also synthesized reduced quantities of 35S-glycosaminoglycans. There were no preferential metabolic alterations of species of 35S-glycosaminoglycans by diabetic glomeruli or aortas. These studies suggest that synthesis of 35S-glycosaminoglycans and 35S-glycopeptides by diabetic glomeruli are altered by disturbances of both synthetic as well as degradative pathways. An alteration of 35S-glycosaminoglycans interaction with matrix components in diabetes is postulated.