Adipose tissue cells in cold-acclimatised sheep.

The morphology and lipid content of adipose tissue from sheep subjected to cold acclimatisation were examined. In two sheep the perirenal adipose tissue contained virtually no triglyceride (less than 2 mg/100 mg wet tissue) and the appearance on electron microscopy was typical of that of a depleted white fat cell. The morphological, chemical and physiological evidence indicates that, in the sheep, white adipose tissue does not revert to brown adipose tissue during depletion resulting from cold acclimatisation.

An additive effect of cold exposure and hypoxia on pulmonary artery pressure in sheep.

When shorn sheep were exposed to cold (3 degrees C) pulmonary artery pressure (PPA) increased by 24 per cent. When they were caused to breathe an air mixture containing only 11 per cent oxygen there was a similar rise in PPA (27 per cent). During simultaneous exposure to 3 degrees C and low oxygen tension, the rise in PPA was greater than the sum of the two separate treatments (61 per cent).