1. An improved procedure for the isolation of neurosecretory granules from the posterior lobe of the @entity291 pituitary gland is described. 2. Of the total oxytocic and pressor activities present in the original tissue 80% was sedimentable. 3. The granules were separated from mitochondria by prolonged centrifugation in a @entity969 density gradient. During a sedimentation period of 5hr. the granules moved progressively into denser regions of the gradient and the mitochondria remained at the top. 4. The biological activities of the granules were measured: the oxytocic activity was 11.56+/-1.63 and the pressor activity was 15.60+/-3.91 units/mg. of protein. 5. A protein was isolated from a lysate of granules prepared from 40 pituitary glands. @entity535 analysis showed that it consisted of a mixture of neurophysin-I and @entity68282 in equal proportions. It accounted for 60% of the soluble granule protein and for 50% of the total granule protein. 6. The neurophysins present in the granules are associated with 19.1 units of oxytocic and 21.1 units of pressor activity/mg. of protein. 7. Starch-gel electrophoresis revealed the presence of both neurophysins in extracts of 15 pituitary glands studied individually. 8. We conclude that the polypeptide hormones, @entity398 and @entity1831 , are normally closely associated with the two neurophysins within neurosecretory granules of the pituitary gland.

The isolation of @entity68282 from XXXX pituitary neurosecretory granules separated on a large scale from other subcellular organelles. Demonstration of slow equilibration of neurosecretory granules during centrifugation in a @entity969 density gradient.

@entity398 :: ('MESH:D010121', 'Chemical') :: ['oxytocin'] @entity1831 :: ('CHEBI:34543', 'Chemical') :: ['[8-arginine]-vasopressin'] @entity535 :: ('CHEBI:33704', 'Chemical') :: ['Amino acid'] @entity969 :: ('MESH:D013395', 'Chemical') :: ['sucrose'] @entity68282 :: ('280728(Tax:9913)', 'Gene') :: ['neurophysin-II'] @entity291 :: ('9913', 'Species') :: ['bovine']
@entity291 :: (9913,Species) :: ['bovine']
