Isolation and some observations of the properties of a bovine neurohypophysial milk-ejecting factor.
A substance possessing milk-ejecting activity has been isolated from an acetone powder preparation of bovine posterior pituitary glands by Sephadex G-25 chromatography of the neurophysin-neurohypophysial hormone complex. While the material possessed an oxytocic activity of 2.8 IU/mg as measured on the isolated rat uterus, the milk-ejecting activity was more than three fold greater, 9.6 IU/mg. The peptide had an antidiuretic activity of 0.133 IU/mg and a pressor activity of 0.083 IU/mg. Neither the uterine-stimulating action nor the pressor activity was destroyed by incubating the peptide with 0.01 M sodium thioglycollate at 65 degrees C for 5 min. The oxytocic activity was antagonized neither by 1.4 X 10(-6) M atropine nor 3.3 X 10(-7) M phenoxybenzamine.
D000596:Amino Acids / Q000032:analysis; D000818:Animals; D001127:Arginine Vasopressin / Q000494:pharmacology; D001681:Biological Assay; D002417:Cattle; D004305:Dose-Response Relationship, Drug; D005260:Female; D007774:Lactation / Q000187:drug effects*; D008297:Male; D008321:Mammary Glands, Animal / Q000502:physiology*; D008893:Milk Ejection / Q000187:drug effects*; D010121:Oxytocin / Q000494:pharmacology; D010904:Pituitary Gland, Posterior / Q000502:physiology; D010909:Pituitary Hormones, Posterior / Q000302:isolation & purification* / Q000494:pharmacology; D011247:Pregnancy; D051381:Rats; D013329:Structure-Activity Relationship; D014599:Uterus / Q000187:drug effects
D000596:Amino Acids; D010909:Pituitary Hormones, Posterior; D001127:Arginine Vasopressin; D010121:Oxytocin