Enzyme immunoassay for measuring lipoprotein lipase activator in milk.

A method for determining the relative amount of lipoprotein lipase activator in milk was developed. The activator was measured in arbitrary units which were based on a standard curve for high density lipoprotein. Activator varied between cows not only in whole milk but also in skim milk and milk serum. Most of the activator was in the skim milk, and the amount of activator in milk serum varied between 32 and 91% of that in skim milk. In seven of eight cows, free fatty acids of milk increased with increasing units of activator.