Responses of the vascular-interstitial-lymph system to saline loading in the rat

The responses of the vascular-interstitial-lymph system to saline loading were examined in rats by continuous monitoring of circulating blood volume and simultaneous collection of thoracic duct lymph. About 90% of the infused volume shifted out of the intravascular space, of which 72% was imbibed in the interstitial space, 21% was drained through the thoracic duct, and 7% was excreted in the urine by the 50th min after the infusion amounting to 4% of body weight. The drainage of lymph protein following the infusion was about 50% of that expected from the interstitial protein concentration and even distribution of the infused saline. This result can be explained partly by the increase of lymph from skin and muscle after the infusion.