The effects of acclimation to alternating environmental temperature on metabolic and endocrine responses in guinea pigs, during acute heat and cold exposure
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Male Guinea pigs (n=80) were divided into four groups and maintained in a climatic chamber for three weeks in one of the following environmental conditions: (1) Ta20°C and 55% RH; (2) Ta35°C and 30–35% RH from 08:00 to 20:00 h and 5°C; 60–65% RH, from 20:00 h to 08:00 h; (3) Ta5°C and 60–65% RH; (4) Ta35°C and 30–35% RH. At the end of this period the animals were exposed to either −5°C, 60–65% RH or 45°C, 30–35% RH, for a period of 20 min, following which Tre, plasma 11-OHCS, thyroxin, glucose, and FFA, and body and organ weights were determined. The cold-warm adapted animals seemed to develop a more efficient adaptability to acute heat and cold exposure. It is suggested that on acute exposure to severe environmental conditions the endocrine and the nervous system play a dominant role in maintaining optimal body temperature, while on chronic exposure the metabolic rate of the various organs becomes relatively more important.
KeywordsGlucose Body Temperature Metabolic Rate Dominant Role Thyroxin
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