PLASMA AND TISSUE PROTEINS PRODUCED BY NON-HEPATIC RAT ORGANS AS STUDIED WITH LYSINE-ε-C(14) : GAMMA GLOBULINS THE CHIEF PLASMA PROTEIN FRACTION PRODUCED BY NON-HEPATIC TISSUES

The non-hepatic tissues in a perfused "carcass" (caudal half of the rat) maintain some physiological functions for as long as 5 to 6 hours of perfusion, including good clearance of lysine-ε-C(14) and glucose from the perfusate, and synthesis of both tissue and plasma proteins. The perfused "carcass" tissues incorporate only small amounts of lysine-ε-C(14) into the plasma proteins to an extent not markedly affected by the presence of the gastrointestinal tract, pancreas, spleen, or kidneys. This activity is found only in the globulin fraction obtained by sodium sulfate fractionation. No significant activity was detected in the plasma fibrinogen or albumin fractions. C(14)-labeled plasma proteins obtained from the eviscerated surviving rat 6 hours after intravenous lysine-ε-C(14) have been separated by zone electrophoresis. The gamma globulins contain most of the C(14) activity, with small but measurable activity in the beta and alpha globulins, and no activity in the albumin fraction.