RESUMO
1. Indirect calorimetry was used to determine metabolic rates in subadult polar bears at rest after human-controlled disturbance and at four rates of locomotion. 2. Disturbance factors that do not result in locomotion would only have a significant effect on energy expenditure if they occurred over an extended period of time. 3. Human disturbance resulting in locomotion would have a relatively high energetic cost to individual animals. 4. Polar bears may require a relatively high energetic output to initiate walking.
Assuntos
Metabolismo Energético/fisiologia , Locomoção/fisiologia , Descanso/fisiologia , Estresse Fisiológico/veterinária , Ursidae/metabolismo , Animais , Humanos , Masculino , Estresse Fisiológico/metabolismoRESUMO
Body temperatures and oxygen consumption of three sub-adult polar bears (Ursus maritimus) during treadmill exercise are presented. Comparisons are also made with results from prior studies of polar bear locomotion. The increase in body temperature and the metabolic cost were unexpectedly high, particularly in young animals. An equation describing the cost of locomotion versus body mass shows a negative, and apparently linear relationship. A significant correlation between body temperature and oxygen consumption may permit the use of body temperature telemetry to estimate activity metabolism of free-ranging polar bears.
Assuntos
Temperatura Corporal , Peso Corporal , Carnívoros/metabolismo , Metabolismo Energético , Consumo de Oxigênio , Ursidae/metabolismo , Fatores Etários , Animais , Feminino , Locomoção , Masculino , Esforço Físico , Especificidade da EspécieAssuntos
Bactérias/metabolismo , AMP Cíclico/metabolismo , Indução Enzimática/efeitos dos fármacos , Glucose/farmacologia , Adenilil Ciclases/metabolismo , Transporte Biológico Ativo/efeitos dos fármacos , Proteínas de Transporte/farmacologia , Frutose/metabolismo , Glucose/metabolismo , Hexoses/farmacologia , Mutação , Fosfoenolpiruvato/metabolismo , Fosfotransferases/metabolismoAssuntos
Escherichia coli/metabolismo , Genes , Tioglucosídeos/farmacologia , Tioglicosídeos/farmacologia , Metabolismo dos Carboidratos , AMP Cíclico/farmacologia , Escherichia coli/efeitos dos fármacos , Genótipo , Glucose/metabolismo , Cinética , Mutação/efeitos dos fármacos , Transdução GenéticaRESUMO
The results of serveral studies imply that estrogen can act upon the central nervous system via a protein synthetic step. Our objective was to determine if the intrahypothalamic (preoptic area, POA) injection of cycloheximide (CHX), an inhibitor of protein synthesis, at 17.00 h on diestrus II of the 4-day cycle altered lordotic behavior and (or) ovulation in the intact rat (sexual receptivity to males normally begins on the evening of proestrus as herein defined; ovulation occurs on estrus of the cycle). CHX-treated females were tested for lordotic behavior at 23.00 h on proestrus, then killed at 17.00 h on the following day. None of the CHX-POA rats were receptive to the males and 90% of these rats did not ovulate. Thus, CHX significantly suppressed sex behavior and ovulation in the cyclic rat.