Body Temperature, Oxygen Consumption, and Heart Rate in Three Species of Australian Flying Foxes

1964 ◽  
Vol 37 (2) ◽  
pp. 179-198 ◽  
Author(s):  
George A. Bartholomew ◽  
Philip Leitner ◽  
John E. Nelson
1961 ◽  
Vol 201 (4) ◽  
pp. 723-728 ◽  
Author(s):  
Dorothy A. Piatnek ◽  
Robert E. Olson

A hyperthyroid state was induced and maintained in 17 dogs for 2–10 months by the administration of massive amounts of thyroid hormone. The great tolerance of this species to such large doses was striking. The clinical signs characteristic of hyperthyroidism in other mammals were observed including significantly increased caloric intake, oxygen consumption, heart rate, and body temperature. The laboratory findings included polycythemia, markedly increased levels of protein-bound iodide (PBI), increased turnover rates of l-thyroxine, and a decreased urinary excretion of inorganic iodide. Unlike other species the hyperthyroid dogs did not demonstrate marked reductions in body weight or serum cholesterol. Salivariectomy neither hastened nor enhanced the onset of exogenous hyperthyroidism in the dog. Measurements of the rate of disappearance of I131 l-thyroxine from the plasma and the rate of appearance of radioactive iodide in the urine indicated that the salivary glands in the intact dog are effective sites of deiodination and iodide excretion. This activity, however, is not the sole regulator of the level of circulating thyroid hormone and thus of the thyroid state.


2006 ◽  
Vol 290 (4) ◽  
pp. R881-R891 ◽  
Author(s):  
Roee Gutman ◽  
Itzhak Choshniak ◽  
Noga Kronfeld-Schor

Golden spiny mice, which inhabit rocky deserts and do not store food, must therefore employ physiological means to cope with periods of food shortage. Here we studied the physiological means used by golden spiny mice for conserving energy during food restriction and refeeding and the mechanism by which food consumption may influence thermoregulatory mechanisms and metabolic rate. As comparison, we studied the response to food restriction of another rocky desert rodent, Wagner’s gerbil, which accumulates large seed caches. Ten out of 12 food-restricted spiny mice (resistant) were able to defend their body mass after an initial decrease, as opposed to Wagner’s gerbils ( n = 6). Two of the spiny mice (nonresistant) kept losing weight, and their food restriction was halted. In four resistant and two nonresistant spiny mice, we measured heart rate, body temperature, and oxygen consumption during food restriction. The resistant spiny mice significantly ( P < 0.05) reduced energy expenditure and entered daily torpor. The nonresistant spiny mice did not reduce their energy expenditure. The gerbils’ response to food restriction was similar to that of the nonresistant spiny mice. Resistant spiny mice leptin levels dropped significantly ( n = 6, P < 0.05) after 24 h of food restriction, and continued to decrease throughout food restriction, as did body fat. During refeeding, although the golden spiny mice gained fat, leptin levels were not correlated with body mass ( r2 = 0.014). It is possible that this low correlation allows them to continue eating and accumulate fat when food is plentiful.


The Condor ◽  
1962 ◽  
Vol 64 (2) ◽  
pp. 117-125 ◽  
Author(s):  
George A. Bartholomew ◽  
Jack W. Hudson ◽  
Thomas R. Howell

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