PHOSPHORUS METABOLISM IN COLD-EXPOSED RATS.

Male rats weighing 207 ± 2.38 g were exposed to cold (2–3 °C) for a period of 7 days during which urine and faeces were collected daily and analyzed for phosphorus. As a consequence of cold exposure, urinary excretion of phosphorus is increased. With free access to food, the increased food (and hence phosphorus) intake of the animals compensates for the increased urinary excretion and a normal phosphorus balance results. Cold exposure was without significant effect upon blood concentrations of acid-soluble, inorganic, organic, or lipid phosphorus. Increased inorganic and decreased organic, non-lipid phosphorus levels were observed in livers of cold-exposed rats. These observations suggest the breakdown of organic phosphates (e.g. hexose and triose phosphates, adenosine phosphates, phosphocreatine) to inorganic phosphorus.