THE INFLUENCE OF HYPOPHYSECTOMY, THYROIDECTOMY, AND OF BOTH HYPOPHYSECTOMY AND THYROIDECTOMY UPON THE FAT CONTENT OF THE LIVER OF THE DOG1

The control exercised by pituitary and thyroid glands upon lipid metabolism has been the subject of earlier reports from this laboratory (Chaikoff et al., 1936; Chaikoff et al., 1941; Entenman et al., 1942a and b). Hypophysectomy per se has but little effect on the levels of the blood lipids of the dog (Chaikoff et al., 1936). Provided caloric intake is not restricted, thyroidectomy, on the other hand, produces changes in the concentration of blood lipids of this animal (Chaikoff et al., 1941). Definite elevations in the levels of blood cholesterol esters were observed as early as 7 days after excision of the thyroid gland, and by the time 29 days had elapsed definite increases in total fatty acids were also found. Not all blood lipid constituents, however, responded to the same degree; phospholipids and free cholesterol seldom showed pronounced increases after thyroidectomy.