Influence of Moderate Changes in Blood Volume on Urine Flow

¹ From the Aero Medical Laboratory, Wright Air Development Center, Wright-Patterson Air Force Base, Ohio

Increased filling of thoracic circulation produces a diuresis, while decreased thoracic filling causes oliguria. The validity of an hypothesized volume regulating mechanism can be tested by altering circulating blood volume by isotonic infusions or venesection without altering blood osmolarity. Normal saline, iso-oncotic bovine albumin and canine plasma infusions are followed by diuresis. Hemorrhage induced an oliguria in every experiment. In 18 of 26 experiments, whole blood infusions produced diuresis. In eight of 26 experiments, whole blood infusions produced either no change in urine flow or an antidiuresis. Donor blood under certain circumstances contains antidiuretic substance which modifies the recipient's response to increased blood volume. Rat assay for antidiuretic hormone supports this hypothesis.