Factors affecting thermogenic drinking in rats.

After as little as 6 h of exposure to cold air, drinking was induced in rats following transfer from air at 5 degreesC to air at 26 degreesC. Drinking began within 15 min after transfer from the cold enviroment and lasted approximately 1 h. The stimulus for initiation of drinking was most likely the temperature change resulting from the transfer, since an ambient temperature difference of 10 centigrade degrees or more was required to initiate a drinking response after transfer from air at 5 degreesC. Thermogenic drinking was not thwarted by preventing access to water for either 1 or 2h following transfer to warm air, but either intragastric or intraperitoneal administration of a water load equal to 3% of body weight inhibited water intake following transfer.The characteristics of the drinking response following transfer than 5 to 26 degrees C were similiar to those observed following 24 h of dehydration at 26 degrees C. Thus, the cold-exposed rat is relatively dehydrated compared with controls.