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Liver Na+K+-ATPase activity and circulating levels of corticosterone and thyroid hormones following cold and heat exposure in the pigeon

1985; Elsevier BV; Volume: 80; Issue: 1 Linguagem: Inglês

10.1016/0300-9629(85)90686-3

0300-9629

B. Pilo, T.M. John, John C. George, R. J. Etches,

Meat and Animal Product Quality

1. 1. Changes in the levels of Na + K+-ATPase activity in the liver and corticosterone and thyroid hormones (T4 and T3) in the blood of fully feathered (FF) and partially defeathered (PD) pigeons, exposed to cold (−15°C, 90min) and heat (+ 45°C, 90min), were studied. 2. 2. Cold-exposed FF and PD pigeons showed an increase in liver Na+K+-ATPase activity but heat-exposed FF pigeons showed a decrease. No significant change was seen in the heat-exposed PD pigeons. 3. 3. No significant change in serum T4 level was seen in either cold- or heat-exposed FF or PD pigeons. Significant increase in the serum T3 level was seen in cold-exposed FF and PD pigeons but there was no change in the heat-exposed pigeons. 4. 4. Cold or heat exposure caused significant increase in serum corticosterone in both FF as well as PD pigeons. 5. 5. Increased liver Na+K+-ATPase activity in pigeons exposed to cold has been attributed to increased heat production (non-shivering thermogenesis) in the liver and the decreased enzyme activity in the heat-exposed pigeons, to thermosuppression. 6. 6. The higher concentration of T3 in the blood of cold-exposed pigeons was indicative of peripheral deiodination of T4 to promote thermogenesis.