scholarly journals Changes in the oxygen consumption of new-born guinea-pigs and rabbits on exposure to cold

1963 ◽  
Vol 168 (1) ◽  
pp. 22-42 ◽  
Author(s):  
G. S. Dawes ◽  
G. Mestyán
Keyword(s):  
Oxygen Consumption ◽  
Guinea Pigs ◽  
New Born ◽  
Exposure To Cold

Respiratory Metabolism During Pregnancy in the Guinea Pig

1957 ◽  
Vol 190 (3) ◽  
pp. 425-428 ◽  
Author(s):  
Richard M. Hoar ◽  
William C. Young
Keyword(s):  
Heart Rate ◽  
Oxygen Consumption ◽  
Guinea Pig ◽  
Metabolic Rate ◽  
Adrenal Cortex ◽  
Guinea Pigs ◽  
Sharp Decrease ◽  
Zona Fasciculata ◽  
Respiratory Metabolism ◽  
Morphological Differences

Oxygen consumption and heart rate during pregnancy were measured in untreated, thyroxin-injected and thyroidectomized guinea pigs given I131. From impregnation until parturition, oxygen consumption increased 7.9% in untreated females. The increase continued until 5 days postpartum when a sharp decrease occurred. The increase is not accounted for by growth of the fetal mass. Comparable increases occurred in thyroxin-injected (16.2%) and thyroidectomized (11.9%) females, although the levels throughout were higher and lower, respectively, than in intact females. Heart rate did not increase. On the contrary, statistically significant decreases occurred in the untreated and thyroxin-injected females. Although the mechanism associated with the increased metabolic rate is not known, the possibility of thyroid participation would seem to be excluded. Involvement of the adrenal cortex is suggested by morphological differences in the cells of the zona fasciculata in pregnant and nonpregnant females and by evidence cited from other studies.

Tolerance of estrogen-treated rats to acute cold exposure

1979 ◽  
Vol 47 (1) ◽  
pp. 59-66 ◽  
Author(s):  
M. J. Fregly ◽  
D. L. Kelleher ◽  
D. J. Black
Keyword(s):  
Oxygen Consumption ◽  
Cold Exposure ◽  
Previous Experiment ◽  
Female Rats ◽  
Control Group ◽  
Maximal Rate ◽  
Acute Cold Exposure ◽  
Exposure To Cold ◽  
Rate Of Oxygen Consumption ◽  
Rate Of Cooling

Female rats treated chronically with ethynylestradiol (36 micrograms/kg per day) alone, and in combination with the progestational agent, norethynodrel (253 micrograms/kg per day), cooled significantly faster than controls when lightly restrained and exposed to air at 5 degrees C. Rate of cooling of rats given only norethynodrel was similar to that of the control group. In other studies, rate of oxygen consumption was determined for all groups during acute exposure to cold (14 degrees C). All estrogen-treated groups achieved the same maximal rate of oxygen consumption as control and norethynodrel-treated groups during cold exposure, but cooled significantly faster. Two groups of female rats were treated chronically with ethynylestradiol at two separate doses (36 and 61 micrograms/kg per day). An untreated group served as controls. Rate of oxygen consumption of all animals were measured during restraint and exposure to cold (18 degrees C). The estrogen-treated groups again achieved the same maximal rate of oxygen consumption as the control group, but also cooled significantly faster despite the fact that the cold stress was less severe than in the previous experiment. That estrogen-treated rats cooled faster than controls in both studies despite achieving a maximal rate of heat production which did not differ from controls suggests that reduced cold tolerance of estrogen-treated rats may be related to increased heat loss.

Oxygen Consumption Following Whole-Body X-Irradiation of Guinea Pigs

1952 ◽  
Vol 81 (1) ◽  
pp. 140-141 ◽  
Author(s):  
F. Smith ◽  
W. G. Buddington ◽  
M. M. Grenan
Keyword(s):  
Oxygen Consumption ◽  
Guinea Pigs ◽  
Whole Body ◽  
X Irradiation

Reversibility of endocrine changes produced in guinea pigs by exposure to cold

1965 ◽  
Vol 208 (1) ◽  
pp. 115-117 ◽  
Author(s):  
Harry Sobel ◽  
George C. Haberfelde ◽  
Albert E. Reeves
Keyword(s):  
Glucose Tolerance ◽  
Guinea Pigs ◽  
Room Temperature ◽  
Oral Glucose ◽  
Oral Glucose Tolerance ◽  
Definite Evidence ◽  
Exposure To Cold ◽  
Thyroid Glands ◽  
Oral Glucose Tolerance Tests ◽  
Glucose Tolerance Tests

Guinea pigs were exposed continuously to a temperature of 2–4 C for 6 months. They were then reacclimatized to room temperature, and after 4–6 months certain tests were carried out. During control collections and following exposure to cold the previously cold-exposed animals exhibited urinary corticoid excretion values which were approximately 10% below those of their controls. Following intraperitoneal injection of ACTH the response was approximately 20% greater. However, these differences were not statistically significant. Oral glucose tolerance tests revealed definite evidence of reduction in tolerance in the previously cold-exposed animals. Six animals exhibited 150-min values which exceeded by more than 20 mg/ 100 ml the highest value observed in the controls. Fourteen others whose values fell within this limit exhibited a statistically significant increase in the 150-min value as compared with the controls. The PBI values were the same in each group. There were no histological residues in the pituitary, adrenal, pancreas, and thyroid glands.

scholarly journals OXIDATIVE PHOSPHORYLATION IN MITOCHONDRIA FROM LIVERS SHOWING CLOUDY SWELLING

1956 ◽  
Vol 2 (3) ◽  
pp. 293-299 ◽  
Author(s):  
Alberto Fonnesu ◽  
Clara Severi
Keyword(s):  
Oxygen Consumption ◽  
Oxidative Phosphorylation ◽  
Guinea Pigs ◽  
Diphtheria Toxin ◽  
Cellular Change ◽  
Normal Controls

Using succinate and α-ketoglutarate as substrates, oxidative phosphorylation has been measured in mitochondria isolated from livers showing cloudy swelling. This cellular change was obtained by injecting rats with S. typhi murium toxin and guinea pigs with diphtheria toxin. It has been found that phosphorylation associated with the oxidation of either of these substrates was partially inhibited in mitochondria from livers showing cloudy swelling, while the oxygen consumption was unchanged. Thus, the P:O ratios for both succinate and α-ketoglutarate were lower in mitochondria from treated animals than they were in normal mitochondria. Dephosphorylation of ATP was not significantly modified in mitochondria from livers showing cloudy swelling as compared with normal controls. No dephosphorylation of AMP and G-6-P was observed either in normal mitochondria or in mitochondria from treated animals.

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