A Proposal for a Reference Standard Preparation for the Hypothalamic Thyrotrophic Hormone Releasing Factor

ANY programme which proposes to purify and isolate a biologically active material for which there is no specific physico-chemical mode of identification is on solid ground when it has at its disposal a bioassay and some reference standard preparation. The bioassay must be specific, reliable (reproducible), preferably sensitive, and able to demonstrate a linear increment of the measured meta-meter as a function of the log of the dose of the biological material injected. A reference standard preparation must be an isologous material which will give responses as a function of the doses injected, varying with slopes of that function identical to those observed when comparing the responses obtained with injection of purified materials along the course of the isolation procedure.