Dietary modifications of cold-induced metabolic effects

Cold-exposed male Sprague-Dawley rats were forced to obtain their extra caloric requirements from either carbohydrate (sucrose) or fat (Crisco). Rats were killed 1, 4, and 8 weeks after initiation of the feeding regimen. Carcass fat, protein, and moisture analyses were made. Liver glucose-6-phosphatase, HMP dehydrogenase, and glycogen were assayed. At the end of 4 and 8 weeks the percentages of fat in the carcasses of these rats were significantly higher than in the cold rats receiving a mixed complete diet ad libitum. The 2 enzymes studied showed differing responses, HMP dehydrogenase increasing as a result of higher input of carbohydrate in the cold, and G-6-Pase increasing as an apparent result of cold exposure per se.