Renal effects of glucagon-like peptide in rats

The present study examined the effects of recombinant glucagon-like peptide-1-(7-36)amide (rGLP-1) on renal hemodynamics and excretory function in innervated and denervated kidneys of anesthetized rats. Intravenous infusion of rGLP-1 at a dose of 1 microg x kg(-1) x min(-1) increased urine flow and Na(+) excretion 13-fold in the innervated kidney. The natriuretic and diuretic response to rGLP-1 was attenuated in the denervated kidney in which urine flow and Na(+) excretion only increased 3-fold. Fractional excretion of Li(+), an index of proximal tubular reabsorption, increased 219% in the innervated kidney but only 54% in the denervated kidney during infusion of rGLP-1. The diuretic and natriuretic response to rGLP-1 was associated with an increase in glomerular filtration rate (39%) in the innervated kidney, but it had no effect on glomerular filtration rate in the denervated kidney. These results indicate that the natriuretic and diuretic effects of rGLP-1 are due to inhibition of Na(+) reabsorption in the proximal tubule. It also increases glomerular filtration rate in kidneys with an intact renal innervation.