Effects of arginine vasopressin on the sequestration of albumin in extravascular space in the rat.

1. The effect of Arginine-Vasopressin (AVP) and phenoxybenzamine on regional sequestration of albumin in the extracellular space was studied in anesthetized (Na-Thiopentone) rats using a dual albumin labelling technique. 2. Low AVP dose (400 microU/kg) resulted in increased albumin sequestration, particularly in cutaneous and skeletal muscle extravascular space. In higher AVP doses this effect was not pronounced. 3. Phenoxybenzamin resulted in increased albumin sequestration, mostly in cutaneous and skeletal muscle extravascular space. 4. The effect of AVP, a potent pressoric hormone, on albumin sequestration resembles that of a vasodilator drug and contrasts with its pressoric nature.