CORTICOTROPIN-RELEASING FACTOR-LIKE ACTIVITY IN HUMAN PLACENTAL EXTRACTS

Corticotropin-releasing factor (C R F)-like activity, which was first found in the hypothalamus, was detected in the extracts of human placentas obtained at full term from spontaneous deliveries. The molecular size of the placental CRF-like substance is slightly larger than that of adrenocorticotropin. In cultures of rat anterior pituitary cells, the placental CRF-like material shows bioactivity similar to that of the partially purified rat hypothalamic CRF and synthetic ovine C R F on the release of adrenocorticotropin and (β-endorphin. Furthermore, the CRF-like activity from human placenta was attenuated by trypsin digestion. Thus the human placenta may elaborate a substance similar to hypothalamic CRF.