Diabetes, Vol 38, Issue 7 839-846, Copyright © 1989 by American Diabetes Association
Effects of sorbinil on glomerular structure and function in long-term-diabetic rats
SM Mauer, MW Steffes, S Azar and DM Brown
Department of Pediatrics, University of Minnesota, Minneapolis 55455.
We investigated the role of the aldose reductase pathway in the
pathogenesis of the nephropathy of rats with sever (non-insulin-treated)
streptozocin-induced diabetes of 6 mo duration. The initial experiment
included four groups of rats: diabetic and control animals on a 20% protein
diet, which were untreated or treated with sorbinil (an aldose reductase
inhibitor). Food intake was increased by diabetes but was uninfluenced by
sorbinil, whereas urinary urea nitrogen excretion was increased and body
weight was decreased by both variables. Glomerular basement membrane (GBM)
width was increased by diabetes and decreased by sorbinil. No other
structural changes were noted. We speculated that sorbinil could have
slowed the abnormal rate of GBM thickening in diabetic rats and the normal
increase in GBM width in control rats by inducing a mild catabolic state.
The second experiment also involved four groups of rats: diabetic and
control animals on a 50% protein diet, which were untreated or treated with
sorbinil. In these studies, diabetes was again associated with reduced body
weight, but sorbinil had no influence on urinary urea nitrogen. Urinary
albumin excretion, which was increased by diabetes, was not affected by
sorbinil. GBM width was increased by diabetes, but in contrast to animals
on 20% protein diets, the animals on 50% protein diets and treated with
sorbinil did not have reduced GBM widths. Mesangial volume fraction was
greater in diabetic animals than in controls, and sorbinil largely
prevented mesangial expansion in them. Surprisingly, the control animals on
the 50% protein diet and given sorbinil had increased mesangial volume
fraction compared with control rats on the same diet not given the
drug.(ABSTRACT TRUNCATED AT 250 WORDS)