Effect of Glomerulopressin and a Rabbit Glomerulopressin-Like Substance in the Rat

Abstract

Plasma volume (PV) expansion induces the toad liver to produce an hormone, glomerulopressin, that increases the glomerular pressure in the toad. In this report we have studied the effect of intravenous infusion of glomerulopressin on the rat glomerular filtration rate (GFR). The possibility that PV expansion induces the rabbit liver to release a glomerulopressin-like substance was also investigated.

Blood was collected from the hepatic vein in normal rabbits, in rabbits with expanded PV, and from the vena cava of PV expanded rabbits.

The effect of the different concentrated ultrafiltrates was assayed on the rats GFR and on the toads glomerular pressure index (GPI).

Glomerulopressin and the ultrafiltrate of plasma obtained from the hepatic vein of PV expanded rabbits produced an increase in the rats GFR, and in the toads GPI without altering the osmotic excretion. The ultrafiltrate obtained from the hepatic vein of normal rabbits or from the cava vein of expanded rabbits had no effect on the rats GFR or on the toads GPI.

The evidence supports the conclusion that rats are sensitive to glomerulopressin and also that PV expansion releases a glomerulopressin-like substance from the rabbit liver.

Key words

Plasma Volume Expansion - Glomerular Filtration Rate - Glomerular Pressure - Liver