Failure of Mammalian Thyrotropin-Releasing Factor Preparation To Elicit Metamorphic Responses in Tadpoles

Abstract

Mammalian thyrotropin-releasing factor (TRF) was injected either intracranially in the vicinity of the pituitary gland or into the ventricle of the heart in bullfrog tadpoles. No signof acceleration of metamorphosis was noticed, even after injecting 4 U of TRF. Intra-peritoneal injections of up to 10 U of TRF were similarly ineffective. Possible implications of the failure of the mammalian TRF to elicit a response in the tadpole are discussed.