308 IV. DIGESTION OF LIPIDS OTHER THAN FATS 



that the thyroid gland in some way regulates the transformation of carotene 

 to vitamin A. As early as 1907, von Noorden 382 suggested that the con- 

 dition of carotenemia may be associated with certain metabolic disorders. 

 Anderson and Soley 383 later ascribed this metabolic upset to an alteration 

 in thyroid function. On the basis of the poor dark adaptation of hypo- 

 thyroid patients, Wohn and Feldman 384 concluded that the thyroid gland 

 was in some way connected with carotene metabolism. Escamilla 385 and 

 Mandelbaum et dl. m demonstrated that, in the clinical condition of hypo- 

 thyroidism in man, namely myxedema, carotenemia ensued. Both 

 conditions tended to clear up under treatment with thyroid substance. 

 Wendt 387 reported a low level of serum vitamin A in patients with hyper- 

 thyroidism (Basedow's disease), even though the carotene intake was 

 sufficient to produce a normal value. 



Studies on the relationship between the thyroid secretion and carotene 

 metabolism have furnished considerable information. Thus, Kunde 388 

 noted the appearance of xerophthalmia in rabbits, eight to twenty months 

 after total thyroidectomy. Fasold and Heidemann 389 likewise made the 

 interesting observation that the carotene content of goat milk increased 

 following thyroidectomy, coincident with a decrease in its vitamin A con- 

 tent. Von Euler and Klussmann 390 also pointed out that an antagonism 

 exists between carotene and thyroxine. Drill and Truant 391 likewise 

 reported that thyroidectomy in rats is followed by a depression in the 

 carotene —*■ vitamin A reaction, since it was found to be impossible to 

 relieve ocular symptoms caused by vitamin A deficiency by means of 

 daily doses of /3-carotene amounting to as much as 10 Mg-, although pre- 

 formed vitamin A afforded protection against these lesions. However, 

 Remington et or./. 392 reported that an oral dose of /3-carotene as small as 

 0.6 Mg- was able to bring about a cure of the xerophthalmia in vitamin A- 

 deficient thyroidectomized rats, within seven to nine days. Goodwin 393 

 demonstrated that, in the hyperthyroid rat, the converse of the above 



382 C. von Noorden, Die Zuckerkrankheit, 4th ed., Hirschwald, Berlin, 1907; cited by 

 Y. A. Drill, Physiol. Revs., 23, 355-379 (1943), p. 359. 



383 H. H. Anderson and M. H. Soley, Am. J. Med. Sci., 195, 313-318 (1938). 



384 M. G. Wohn and J. B. Feldman, Endocrinology, 24, 389-396 (1939). 

 386 R. F. Escamilla, J". Clin. Endocrinol, 2, 33-35 (1942). 



386 T. Mandelbaum, S. Candel, and S. Millman, J. Clin. Endocrinol., 2, 465-467 (1942). 



387 H. Wendt, Klin. Wochschr., 14, 9-14 (1935). 



388 M. M. Kunde, Proc. Soc. Exptl. Biol. Med., 28, 812 (1926). 



389 H. Fasold and E. R. Heidemann, Z. ges. exptl. Med., 92, 53-56 (1933). 



390 H. von Euler and E. Klussmann. Z. physiol. Chem., 213. 21-34 (1932). 



391 V. A. Drill and A. P. Truant, Endocrinology, 40, 259-264 (1947). 



392 R. E. Remington, P. L. Harris, and C. L. Smith, ./. Nutrition, 24, 597-606 (1942). 



393 t. W. Goodwin, Biochem. J., 48, xliii-xliv (1948). 



