Some endocrine factors in regulation of fatty acid mobilization during fasting

¹ Department of Physiology, Harvard Medical School, Boston, Massachusetts

In the rat, hypophysectomy, adrenalectomy, or thyroidectomy do not abolish the increase in lipid mobilization normally observed during fasting as evidenced by an increase in the concentration of free (nonesterified) fatty acids (FFA) in the plasma. The magnitude of this response, however, is reduced following the ablation of these glands. In adrenalectomized animals, cortisol administration returns the response to normal. These findings lead to the conclusion that increased secretion by the pituitary, thyroid, or adrenal glands does not initiate FFA mobilization during fasting, but that optimal function of these glands is requisite for the normal metabolic response to food deprivation.