Journal of Nutrition Vol. 64 No. 1 January 1958, pp. 67-83
Copyright © 1958 by American Society for Nutrition
Nutritional Studies with the Hyperthyroid Rat1
C. O. Stevens2 and
L. M. Henderson2
Departments of Chemistry and Chemical Engineering, University of Illinois, Urbana
- 1. Experiments designed to improve the assay for substance(s) in liver and other natural materials which partially reverse the growth suppression of hyperthyroid rats have been reported. A three-week curative assay which gives more reproducible results than the 5-week preventive assay has been developed and used. The assay involves feeding weanling rats a typical synthetic-type sucrose-casein-corn oil diet for one week and then a sucrose-casein-Crisco diet containing 0.243% iodinated casein for two weeks. These depleted, hyperthyroid rats are then used for the assay of liver or other natural products.
- 2. Cholesterol, corn oil or crystalline aureomycin stimulated growth slightly under these assay conditions. A combination of these three substances was almost as effective as 10% liver residue alone. The liver residue plus these three substances supported growth and survival nearly equivalent to that obtained by removing the iodinated casein from the diet.
- 3. Casein and many other proteins or protein-containing supplements were not active. Beef spleen, kidney and lung exhibited some activity. The active substance(s) in pork liver was not soluble in a mixture of chloroform and methanol.
- 4. Removal of iodinated casein from the diet lowered the basal metabolic rate and caused immediate resumption of growth. A liver residue active in stimulating growth did not alter the basal metabolic rate.
1 This investigation was supported by grants from Eli Lilly and Company, Indianapolis, Indiana, and from the National Institutes of Health, Public Health Service (A-801).
2 Present address, Department of Biochemistry, Oklahoma State University, Stillwater, Oklahoma.
Manuscript received 11 July 1957.