Purification and tissue distribution of rat epidermal growth factor.

1. Two forms of rat epidermal growth factor, EGF-I and EGF-II, were purified to homogeneity from male rat submandibular glands. 2. The mol. wts of EGF-I and -II were estimated to be 5200 and 5400, respectively, both of them having an apparent biological activity. 3. The antiserum against EGF-II strongly cross-reacted with EGF-I; however, it did so only slightly with mouse or human EGF. 4. EGF was detected by radioimmunoassay in various tissues of male and female rats, and the concentrations of rat EGF in the submandibular gland, parotid gland, sublingual gland, and liver were significantly higher in the male than in the female.