DIFFERENTIAL EXPRESSION OF RENAL GROWTH-HORMONE RECEPTOR AND ITS BINDING-PROTEIN IN EXPERIMENTAL DIABETES-MELLITUS

Growth hormone (GH) may have a role in the development of diabetic nep hropathy. The effect of experimental diabetes on renal expression of t he growth hormone receptor gene products, including the receptor itsel f (GHR) and its binding protein (GHBP) was examined, Adult female rats received i.v. streptozotocin and were killed at 7, 30, 90 and 180 day s after the induction of diabetes. Diabetic animals had a pronounced i ncrease in kidney weight and progressive albuminuria. In renal cortex, no change was seen in GHR mRNA levels throughout the observation peri od of 6 months, while a significant increase in cortical GHBP mRNA lev els was observed after 1 month of diabetes and sustained for the rest of the study period. Immunohistochemical analysis of kidney sections r evealed a stronger staining for GHBP at the cortical and inner medulla ry areas in the diabetic animals. These data indicate that although th e GHR and GHBP mRNAs originate from the same gene, their renal levels are differentially regulated during the development of experimental di abetic kidney disease, suggesting a functional role for GHBP. (C) 1998 Churchill Livingstone.