Deposition of basement membrane in vitro by normal and diabetic rat renal glomeruli.

Glomeruli isolated from rat renal cortex were incubated with radioactive precursor to study basement membrane production in vitro. Following incubation, basement membranes were purified with a novel technique of osmotic lysis followed by selective solubilization with detergents that leaves the membranes architecturally intact and results in their quantitative isolation. Incorporation of [14C]-proline into basement membrane increased in a linear fashion during the 3 h of incubation studied, with a progressive increase in the specific activity of hydroxy-[14C]-proline in isolated glomerular basement membrane. With identical incubational conditions, glomeruli from streptozotocin diabetic rats incorporated significantly greater amounts of precursor into the extracellular matrix than did glomeruli from nondiabetic animals.