Protein metabolism in the black bear before and during hibernation.

摘要: During 3 to 5 months of hibernation, the American black bear does not defecate, urinate, or require food water. Although loses 15 25% its body weight during this period, there is no significant change in lean mass. No net accumulation usual nitrogenous products protein catabolism can be demonstrated dormant bear, and a decrease urea production hibernation. Because these findings, it has been hypothesized that alter metabolism hibernation by some unknown mechanism. study, metabolis rate turnover four adult male bears was measured before, during, after using 125I-labeled serum albumin from as an indicator 14C-labeled leucine amino acid. For both phases, disappearance labeled over 2 weeks calculated data. [14C]leucine, acid injected appearance total proteins plasma measured. The results revealed threefold increase compared with before Leucine data supported findings; more incorporated than active state spring. There were changes hematocrit, concentration, thyroxin, thyroxine-binding globulin between periods, although triiodothyronine tended We speculate increased suggests strongly acting protein-anabolic mechanism would tend compete other catabolic pathways for acids. Another consequence thermogenesis. This may have helped prevent any undue temperature. It notable temperature appreciably higher hibernating animals.