POSSIBLE ROLES OF SUBMANDIBULAR SALIVARY GLANDS ON OVARIAN STEROIDS RESPONSIVENESS OF MOUSE MAMMARY GLANDS

This experiment was to determine the effect of sialoadenectomy on the ability of the mammary gland development to response to ovarian steroids, estrogen and progesterone, stimulus in vivo. Body weights did not differ between sham-operated and sialoadenectomized mice within 0 to 18 day estradiol + progesterone (E + P) injection (p > 0.05). Sialoadenectomy reduced mammary development scores from 4.6 to 3.9 or from 4.4 to 3.8 in comparison with those of sham-operated mice for the 12 or 18 day E + P injection ($P{\leq}0.05$), however, sialoadenectomized mice with 0, 1, 3 or 6 day of E + P injection slightly decreased mammary development scores relative to those of sham-operated mice. These results indicate that the endocrine factor secreted from submandibular salivary gland appears to be required for the mammary development to respond fully to estradiol and progesterone. Similar results were obtained in the measurement of mammary DNA contents. Mammary DNA contents of sialoadenectomized mice were significantly decreased relative to those of sham-operated mice for the 6, 12 or 18 day E + P injections. Overall results suggest that salivary gland-secreted endocrine factor, presumably epidermal growth factor (EGF), was mammogenic and should interact with ovarian steroids in mammary development.