[Temperature sensitivity of the hypothalamus as affected by an increase in the heat content of the body].

To obtain a vascular thermoregulatory response of the ear floor, the hypothalamus had to be heated by 0.59 +/- 0.03 degrees C. After preliminary intraperitoneal administration of subthreshold amount of heat (195.7 +/- 8.9 cal.) constituting 50.7 +/- 1.8% of the threshold (386.4 +/- 14.3 cal.) the hypothalamus had to be heated by 0.19 +/- 0.01 degree C only to obtain the same response in the animal. The change of own temperature sensitivity of the hypothalamus in increased heat contents of the organism might be an auxiliary mechanism for estimation of the heat contents changes by the organism.