title: Immunoglobulin IgG1 metabolism in new born calves.
abstract: The half-life of IgG1 immunoglobulin was measured in six neonatal calves following a meal of iodine-125 labeled IgG1 in colostrum derived from their dams. The half-life as measured by the decrease in plasma concentration of IgG1 was 19.9 +/- 1.9 days. However, the half-life as measured by the disappearance of [iodine-125]IgG1 from the plasma was 11.5 +/- .6 days. The latter value is closer to the true half-life because it is not affected by endogenous production of IgG1 by the tissues of the young calf. A decrease in the specific activity of plasma [iodine-125]IgG1 with time representing the body "pool" of IgG1 (half-life 25.8 +/- 6.1 days) suggests that the calf from birth to about 20 days of age is capable of synthesizing a significant amount of IgG1 immunoglobulin.
mesh_terms: D000818:Animals; D000831:Animals, Newborn / Q000276:immunology*; D002417:Cattle; D003126:Colostrum / Q000032:analysis; D005260:Female; D006207:Half-Life; D007074:Immunoglobulin G / Q000032:analysis / Q000378:metabolism*; D007457:Iodine Radioisotopes
chemical_list: D007074:Immunoglobulin G; D007457:Iodine Radioisotopes