474 THIAMINE 



(3) Physical State of the Animal. As thyroxine regulates the (basal) 

 metabolism, it is to be expected that hyperthyroidism or the feeding of 

 extra doses of thyroxine will increase the requirements of thiamine. The 

 work of several investigators has confirmed this supposition (e.g., Him- 

 wich et al.,^^ Cowgill and Palmieri,^^ Drill and Sherwood,'^ and Peters and 

 Rossiter.^^ A review of this work is given l)y Drill.^* 



It is obvious also that pregnancy, in particular during the latter half, and 

 lactation increase the requirements of thiamine. There are reports that the 

 thiamine requirement of a rat successfully nursing a litter is five times as 

 large as normal (Evans and Burr,-° Sure,-' and Sure and Walker^^). 



Mills et al}^ have demonstrated that the thiamine requirement of rats per 

 gram of diet increases greatly with old age. The most probable explanation 

 for this fact is the supposition that the efficiency of thiamine utilization is 

 diminished. 



Gerrits^* observed that 38 infants, to 23^^ months of age, never excrete 

 thiamine in the urine, independent of their nutrition. Hamil et al.,^^ work- 

 ing with an improved method for the determination of thiamine, also found 

 low values for the thiamine in the urine during the first days of life. In this 

 respect it is interesting that the thiamine pyrophosphate content of the 

 blood of newborn infants is much higher than the content of the blood of 

 adults.25^ 



(4) The Climate (Temperature) . Kline et al.-^ stated that by raising the 

 environmental temperature from 78°F. to 90°F. the thiamine requirement 

 of the rat is decreased. 



Hegsted and McPhee-'^ later found that on lowering of the environmental 

 temperature the thiamine requirement of rats increased considerably. At 

 78°F. the requirement of adult rats amounted to 164 to 168 y of thiamine 

 per 1000 non-fat calories; at 55°F. the figures were 191 to 203 y. 



15 H. E. Himwich, W. Goldfarb, and G. R. Cowgill, Am. J. Physiol. 99, 689 (1932). 



16 G. R. Cowgill and M. L. Palmieri, Am. J. Physiol. 105, 146 (1933). 



17 V. A. Drill and C. R. Sherwood, Am. J. Physiol. 124, 683 (1938). 



18 R. A. Peters and R. J. Rossiter, Biochem. J. 33, 1140 (1939). 



19 V. A. Drill, Physiol. Revs. 23, 355 (1943). 



20 H. M. Evans and G. O. Burr, J. Biol. Chcm. 76, 263 (1928). 



21 B. Sure, J. Biol. Chem. 76, 685 (1928). 



22 B. Sure and D. J. Walker, /. Biol. Chem. 91, 69 (1930). 



23 C. A. Mills, E. Cottingham, and E. Taylor, Arch. Biochem. 9, 221 (1946). 



2'' W. B. J. Gerrits, Thesis, Amsterdam Noord-Hollandsche Uitgever Maatschappij, 

 1940. 



26 B. M. Hamil, M. N. Coryell, C. Roderuck, iM. Kauc-hor, K. Z. Moyor, M. E. llarri<, 

 and H. II. Williams, A?n. /. Diseases Children 74, 434 (1947). 



251 E. Floryn, and H. Strangers, Acta Physiol. Pharmacol. Necrl. 2, 100 (1951). 

 2" O. L. Kline, L. Friedman, and E. M. Nelson, J. Nutrition 29, 35 (1945). 



27 D. M. Hegsted and G. S. McPhee, ./. Nutrition 41, 127 (1950). 



