Isolation of a mouse submaxillary gland protein accelerating incisor eruption and eyelid opening in the new-born animal.

During the course of our studies on the nerve growth-promoting protein of the submaxillary gland of the mouse (1,2). it was noted that the daily injection of partially purified extracts of the salivary gland into new-born mice resulted in a number of gross anatomical changes in addition to the previously reported effects on the nerve cells. These were (a) precocious opening of the eyelids (as early as 7 days instead of the usual 12 to 14 days), (b) precocious eruption of the teeth (at 6 to 7 days instead of the normal 8 to 10 days), and (c) a marked stunting of the animals with an inhibition of hair growth. We are reporting here the isolation of the factor responsible for the earlier development of the incisors and eyelids. The tooth-lid factor is a heat-stable, nondialysable, antigenic protein, whose most distinctive chemical characteristic is the absence of phenylalanine and lysine. The injection of 0.5 pg per 1.5 g of body weight per day of tooth-lid factor into new-born mice or rats produces a demonstrable biological effect.