Abstract
Summary
Significant CRF activity was found in a fraction with R
f
= 0.82-0.7 or V
E
/V
T
= 0.41-0.48 obtained by gel filtration of acid extracts of pig hypothalami on Sephadex G-25. The activity of this fraction decreased markedly during subsequent purification, particularly in the last two steps. From this fraction, a heptapeptide with significant ACTH releasing activity IN VITRO, was isolated in pure state, and its amino acid sequence was established as H-Phe-Ile-Tyr-His-Ser-Tyr-Lys-OH. This heptapeptide was synthesized by solid phase methods. The CRF activity of synthetic heptapeptide IN VITRO was low but could be potentiated by a cofactor fraction from rat hypothalamic extract.
