STUDIES ON THE CONDITIONS OF ACTIVITY IN ENDOCRINE GLANDS

Abstract

Young vigorous cats, with the spleen denervated, with the spleen extirpated, and in one case with denervated spleen and demedullated adrenals were used for a series of experiments in a glass low-tension chamber. To eliminate the emotional factor, observations were made only after they became accustomed to the surroundings. Restlessness and the discomfort described in animals by early investigators as due to low O tension seemed to be attributable rather to abrupt and extreme reductions of pressure and to lack of familiarity with conditions of the experiment. Gradual reduction to even lower pressures did not produce appreciable emotional disturbance in animals familiarized as described. Besides the experiments in the low-tension chamber, a few observations were made on acute asphyxia brought about by mechanical obstruction of the air passage and a few more on the effects of a mixture of 20% CO2 and normal air. It was found that brief obstruction of the air passage in normal animals is followed promptly by polycythemia, but the effect is probably largely due to the attendant excitement of the animal. Low 0 tensions (5.5-9%), independently of any excitement, induce in cats which remain quiet and serene rapid and shallow respiration, salivation, erection of the hair, and polycythemia. Removal of the spleen is followed by failure of the anoxemic polycythemia. Anoxemic polycythemia evoked about a week after denervation of the spleen may be greater than in the normal animal; it disappears if the adrenal glands are demedullated. Increase of CO2 in the respired air (even to 20%) has little or no effect in producing polycythemia. These results are interpreted as supporting the emergency functions of the sympathico-adrenal system.