Effects of indomethacin on kidney function in type 1 (insulin-dependent) diabetic patients with nephropathy.

We investigated whether the glomerular synthesis of prostaglandins modulates the glomerular filtration rate and albuminuria in diabetic nephropathy. The urinary excretion of immunoreactive prostaglandin E2 (253 pg/min) was significantly elevated in eight Type 1 (insulin-dependent) diabetic women with nephropathy as compared with nine normoalbuminuric Type 1 diabetic women (95 pg/min) and 11 non-diabetic women (132 pg/min), respectively (p less than 0.01). Glomerular filtration rate (single bolus 51Cr-EDTA technique) and albuminuria (radioimmunoassay) were measured twice within two weeks in the eight Type 1 diabetic women with nephropathy. All eight patients were on a diabetic diet without sodium restriction. The study was performed as a randomized double-blind trial, with the patients receiving either indomethacin (150 mg/day) or placebo for three days prior to the kidney function studies. Indomethacin treatment induced a significant reduction in urinary prostaglandin E2 excretion (73%, p less than 0.01), glomerular filtration rate diminished from 120 +/- 18 to 106 +/- 17 ml/min/1.73 m2 (p less than 0.05), albuminuria declined from 148 to 69 micrograms/min (median and range) (p less than 0.05) and fractional clearance of albumin diminished 42% (p less than 0.05). Blood glucose concentrations were comparable during the placebo and indomethacin treatment, 13.4 +/- 4 versus 14.2 +/- 3 mmol/l, respectively. Our results suggest that glomerular filtration rate in early diabetic nephropathy is dependent on the enhanced glomerular synthesis of vasodilating prostaglandins.