DETERMINATION OF TRANSFORMING GROWTH-FACTOR-BETA-1 (TGF-BETA-1) AND INSULIN-LIKE-GROWTH-FACTOR-1 (IGF-1) IN BOVINE COLOSTRUM SAMPLES

The major growth factors in bovine colostrum are transforming growth f actor-beta s (TGF-beta 1 and TGF-beta 2) and insulin-like growth facto rs (IGF-I and IGF-2). Recently, TGF-beta 2 content of bovine colostrum was measured using a TGF-beta 2 specific ELISA (1) and now we have va lidated ELISAs for for bovine TGF-beta 1 and IGF-1. The concentrations of IGF-1 and TGF-beta 1 in the first milking after calving were 248-1 850 ng/ml and 12.4-42.6 ng/ml, respectively, and they declined in corr elation with total protein concentration to 27.0-101 ng/ml (IGF-I) and 0.80-3.49 ng/ml (TGF-beta 1) by the fifth milkings. The amount of TGF -beta 1 was on average 5.3+/-1.4% of that of TGF-beta 2 and there is a high correlation (r=0.966) between the concentrations of these growth factors in the same samples. No free TGF-beta 1 form of could be dete cted.