Certain characteristic features of the lipolytic factor from rat submaxillary salivary glands.

The aqueous extract of rat salivary submaxillary gland was found to contain three protein fractions activating the release of free fatty acids (FFA) and glycerol from rat epididymal adipose tissue in vitro. Physico-chemical investigations of these proteins demonstrated certain common features: all three fractions were albumins having a common isoelectric point, and their aqueous solutions absorbed light at the same wavelength. The use of lipolysis activators and inhibitors (theophylline, propranolol, insulin) for investigating their effects on FFA and glycerol release produced by these protein fractions explained the mechanism of the lipolytic action of the protein fractions from rat submaxillary glands.