[Mechanism for maintaining blood protein composition with various protein regimens]

The study of the blood plasma protein content, turnover constant and half-life of albumin, fibrinogen and the total fraction of IgG + transferrin, was conducted in 70 male Wistar rats which received rations containing 4, 8, 12, 18 and 36% protein (casein), during a month. The total serum protein content and the proteins assayed in the blood plasma were not reliably changed in relation to the protein level in the animals' ration. It was found that the half-life of the proteins studied increased with the lowering of the protein content in the ration. It is suggested that the increase of the blood plasma protein half-life is one of the mechanisms of maintaining stable blood plasma protein composition in case of insufficient protein content in the food ration.