Gastric mucus production in Rana pipiens

¹ Department of Physiology, University of Illinois, Urbana, Illinois

The production of gastric mucus in vitro by Rana pipiens was studied using histamine stimulation. The frogs were kept at a constant temperature (21 C) both prior to and during experimentation. Quantitative determinations of mucoproteose, mucoprotein, and mucoid of the visible mucus were performed over a 13-month period, utilizing 340 animals in terminal experiments. Mucoproteose constituted one-half of frog gastric mucus, the rest being divided almost equally between mucoprotein and mucoid. No significant differences in this ratio or in the total amount of gastric mucus could be attributed to the change of seasons or to the addition of glucose or inosine triphosphate as substrates. A statistically significant negative correlation exists between both total mucus and mucoproteose and total acid produced. The mucoproteose fraction of gastric mucus may contain the inhibitor found by other investigators in human gastric juice. However, until further information is available on its physiological significance in situ, gastric mucus cannot be considered responsible for the seasonal variation of gastric HCI secretion in Rana pipiens.