Abstract
An assay method for corticotropin releasing activity was described. In this method, use was made of direct microinjection of test materials into the adenohypophysis, exposed parapharyngeally, of dexamethasone-Nembutal blocked female rats. Possible spread of the injected materials to nearby neural structures was excluded by studying the distribution of 86Rubidium solution after intrapituitary injection. The adrenal and pituitary responsiveness of the assay animal was found to be sufficiently high. By use of this assay method it was shown that acetic saline extracts of the median eminence and posterior pituitary lobe of the rat exhibited a significant CRF activity, whereas nia detectable activity was observed in those of the brain cortex, midbrain and plasma.
It is proposed that direct microinjection. of test materials into the parapharyngeally exposed pituitary is a reliable and practical assay method for CRF activity.
