Effects of vasoactive intestinal polypeptide on renal function in man

Area of Science:

• Physiology
• Pharmacology
• Neuropeptides

Background:

• Vasoactive intestinal polypeptide (VIP) is a neuropeptide with known vasodilatory effects.
• Its impact on renal function and fluid balance requires further elucidation.

Purpose of the Study:

• To investigate the physiological effects of intravenous vasoactive intestinal polypeptide (VIP) infusion in healthy human subjects.
• To assess VIP's influence on cardiovascular parameters, renal hemodynamics, and electrolyte/water excretion.

Main Methods:

• Six healthy males received a continuous intravenous infusion of VIP (6 pmol kg-1 min-1) for 90 minutes.
• Cardiovascular, renal plasma flow, glomerular filtration rate, hematological parameters, and urinary output were monitored before, during, and after VIP infusion.

Main Results:

• VIP infusion induced generalized vasodilation, indicated by changes in heart rate and blood pressure.
• No significant alterations were observed in effective renal plasma flow or glomerular filtration rate.
• Plasma solids and hematocrit increased, suggesting hemoconcentration. Urine flow decreased significantly, along with fractional excretion of sodium, potassium, chloride, and calcium.
• Plasma renin activity increased approximately threefold during VIP infusion.

Conclusions:

• VIP administration in healthy males causes vasodilation and hemoconcentration without impairing fundamental renal filtration or plasma flow.
• The observed decrease in urine output and electrolyte excretion, coupled with increased plasma renin activity, suggests complex interactions between VIP and the renin-angiotensin-aldosterone system and renal tubular function.