Response of Castrated Male and Female Hyperthyroid Rats to Vitamin B 12 . ∗

Abstract

Summary

The growth response of normal and castrate hyperthyroid rats to supplementation with vit. B₁₂ and liver concentrate powder has been investigated. Both supplements were effective in partially counteracting the growth depression induced by feeding toxic levels of iodinated casein to normal and castrate rats of both sexes. Vit. B₁₂ was less effective than 1:20 liver powder for normal males and oophorectomized females. There were little difference in response to these supplements in normal females and castrate males. A sex difference in the growth response of the hyperthyroid rat to a factor present in liver concentrate and not identical with vit. B₁₂ is suggested.