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.