Physiologic Control of Two Neurophysins in Humans

Two human neurophysins, nicotine stimulated neurophysin (NSN), and estrogen stimulated neurophysin (ESN) were assayed during physiologic maneuvers and pathologic states in man. NSN is thought to be associated with vasopressin and was elevated in some subjects by volume depletion, surgical stress, hypotension and hypertonic saline infusion. Overnight dehydration did not elevate NSN in spite of urinary concentration. NSN was elevated in some subjects with the syndrome of inappropriate secretion of antidiuretic hormone and when tested was unresponsive to administered water, alcohol or nicotine. ESN was elevated during estrogen administration, in pregnancy, in newborns and in patients with cirrhosis. NSN was also acutely increased at parturition. These data support the association of NSN with vasopressin although changes in NSN were found only with potent stimuli for vasopressin release. ESN may be associated with oxytocin but demonstration of this awaits knowledge of oxytocin physiology in humans.