METABOLIC ADAPTATIONS FOR DESERT SURVIVAL IN THE BEDOUIN GOAT

Energy conservation is a key adaptation for desert survival in the Bed ouin goat. When food is scarce, metabolism is reduced and body weight can be maintained indefinitely on less than one-half of normal intake. We hypothesized that metabolism would be turned down during both rest and exercise, but it was not. It was low when animals rested and retu rned to normal during exercise. We expected catecholamines and thyroid hormones would modulate metabolism, but they did not. The reduction i n metabolism preceded any change in thyroid hormone concentrations, an d infusions of epinephrine did not restore reduced metabolism to norma l levels. Finally, we expected the gut would be the major organ system involved in the metabolic reduction because less food is eaten, proce ssed, and absorbed. Contrary to our expectations, we found that muscle is the primary organ system responsible for the reduction. It appears that the adaptations of the Bedouin goat for surviving on limited foo d supplies involve different organ systems and different modulators to reduce metabolism from those known for other mammals.