Submaxillary Gland Factors Alter Uterine Weight and Peroxidase Activity in Mice

To elucidate a functional significance of submaxillary gland, a simple in vivo biological assay for uterine growth inhibitory activity of submaxillary gland extract has been developed based on its inhibition of serum gonadotropin induced uterine growth of immature mice. Regression of weight gain after administration of serum gonadotropin was found sigmoidal against protein concentration of submaxillary extract. The inhibitory activities of submaxillary glands were also confirmed in rats, mice, and goats. Parotid and sublingual glands had very little inhibitory activity. Surgical removal of submaxillary glands from female mice increased both uterine weight and peroxidase activity and mice submaxillary extract administration attenuated the increased effect of submaxillary removal, while rat submaxillary extract had less effect on both parameters. Using ammonium sulphate fractionation, the factor was partially purified over crude extract. The submaxillary gland factor(s) is soluble protein, non-dialyzable, heat labile, susceptible to trypsin digestion in crude form, and present in 40-70% ammonium sulphate fraction. The present data suggest that submaxillary gland contains inhibitory factor(s), which inhibits the uterine weight and peroxidase activity in mice.