Infection with Trypanosoma lewisi in the Hypophysectomized Rat

Abstract

Trypanosoma lewisi is a natural parasite of the blood of wild rats, and can be transferred easily to laboratory rats. After inoculation to normal adult rats, it produces a blood stream infection of considerable intensity, although only rarely does the infected animal die. At the end of a patent period ranging from a few day to several weeks, the animals usually clear themselves of the infection and thereafter wholly resist reinfection with this parasite. 1 In the present paper are reported the results of infecting hypophysectomized rats with Trypanosoma lewisi. As will be seen, the hypophysectomized rat dies after infection with this parasite, death occurring in most cases 5 days after the parasite is injected.

Procedure. The experimental work was designed: (1) to compare infection with Tryp. lewisi in hypophysectomized rats with that in control rats,∗ and (2) to study the effect of the administration of anterior pituitary extract upon the infection in the hypophysectomized rats. Thirty-three rats 60 days old were used for the first purpose of the work, 19 being hypophyseetomized† and 14 serving as controls. At infection, all animals were given one million Tryp. lewisi intraperitoneally. The hypophysectomized rats, together with 12 of the control rats which were subjected to the identical operative procedure except for the removal of the hypophysis, were infected from 5 to 10 days after operation. The 2 remaining control rats were normal unoperated animals. For the second purpose of the work, 14 hypophysectomized rats, infected 5 days after operation, were treated subcutaneously or intraperitoneally daily with 10 rat units of E. R. Squibb and Sons′ anterior pituitary extract ‡ beginning the first day after operation and continuing until death or recovery from the infection.