THE EFFECT OF INTERMITTENT INDOOR COLD EXPOSURE ON WHITE RATS

Publisher Website
Google Scholar
Abstract
Recently it has been shown that when white rats are kept in individual cages and exposed indoors to constant cold temperature or when they are exposed in groups to the outdoor winter conditions, they develop similar degrees of cold resistance and similar metabolic adjustments but they differ in endocrine, insulative, and peripheral adjustments.In an attempt to determine whether variations in temperature alone could be responsible for the type of adjustments developed outdoors, white rats were kept at 30 °C for 4 weeks but exposed to 6 °C for a few hours every day. Through these intermittent cold exposures, the animals developed the same type of acclimation as the one produced indoors by continuous exposure to a constant temperature, but to a lesser degree. Adrenals tended to hypertrophy, body and muscle growth tended to decrease, and over-all insulation appeared to decrease. In contrast to continuously exposed rats, however, they showed no cold injury, no change in ear vascularization, and no thickening of the ear epidermis, probably because the skin was never cooled long enough at any given time for the cold temperature to produce cellular alterations that could not be corrected during the warm periods.
Keywords