The influence of cold or heat adaptation on some biochemical neuroendocrine parameters in infant rats.

The investigations were carried out on 192 Wistar newborn rats of either sex, chronically exposed to cold or heat. 32P-incorporation into cerebral phospholipids, phosphoproteins and nucleic acids (RNA and DNA) as well as 32P-uptake by hypothalamus, pituitary and adrenals were studied. The results showed that both chronic exposure to cold and heat enhance 3-P-incorporation into cerebral phospholipids, phosphoproteins and nucleic acids, the exposure to cold inducing nevertheless more important modifications. 32P-uptake by hypothalamo-pituitary-adrenal axis is also stimulated, this stimulation being higher in 14-day-old rats exposed to cold. The authors discuss the importance of the nature of stress, of the animal age and its level of CNS maturation in the appearance of all these modifications.