Effect of Stress on the Uptake of Radiolabelled Calcium in the Pituitary Gland and the Brain of the Rat

The in vivo uptake of 45Ca by certain areas of the rat brain and by the pituitary gland was investigated under normal conditions and in states of cold stress. The uptake of 45Ca was highest in the pituitary gland followed in decreasing order by the superior colliculus, medulla, cerebellum, thalamus, hippocampus and the cortex. Cold stress conditions induced an increase in uptake of 45Ca in the cortex, hippocampus, cerebellum, medulla and the pituitary gland. Our findings suggest that cold stress induces a change in the permeability for calcium in blood‐brain and blood‐pituitary barriers.