Unidentified Nutrients Required by the Hyperthyroid Rat

Abstract
When rats fed a purified ration containing all known nutrients were rendered hyperthyroid, their growth rate was considerably decreased because of a deficiency in the ration of certain unidentified nutrients. Evidence was presented suggesting that crude food materials contain at least two different unidentified nutrients, some food substances containing one or the other of these nutrients and other food materials containing both. Part but not all of the activity of dried whole liver could be accounted for by its steroid content. Unsaturated fat alleviated partially the growth depression. Its activity appeared to be distinct from that of dried whole liver and probably separate from both of the unidentified nutrients mentioned above.