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LEVELS OF THE OXYTOCIN‐ASSOCIATED AND VASOPRESSIN‐ASSOCIATED NEUROPHYSINS IN PLASMA AND THEIR RESPONSES IN ESSENTIAL HYPERTENSION
Author(s) -
AMICO JANET A.,
CORDER C. N.,
McDONALD R. H.,
ROBINSON A. G.
Publication year - 1984
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1984.tb00085.x
Subject(s) - endocrinology , neurophysins , medicine , vasopressin , oxytocin , supine position , plasma renin activity , chemistry , hormone , natriuresis , saline , blood pressure , renin–angiotensin system
SUMMARY A group of 89 individuals with essential hypertension was evaluated with several measurements including the neurophysin believed to be the human oxytocin neurophysin (OT‐Np), and the human vasopressin neurophysin (VP‐Np). The neurophysins are proteins synthesized within cells of the supraoptic and paraventricular nuclei in conjunction with their respective hormones oxytocin and vasopressin as part of a common precursor molecule and so may reflect the simultaneous presence in plasma of their associated hormones. A poor but statistically significant correlation was noted between levels of OT‐Np and renin activity in plasma (PRA) either supine ( r = 0·248) or erect ( r = 0·255). Levels of OT‐Np averaged 1·75 ng/ml and were inversely correlated with creatinine ( r = ‐ 0·252), supine blood pressure ( r = ‐ 0·450), plasma volume ( r = ‐ 0·327), and 24‐hour urine sodium ( r = ‐ 0·313). Levels of Ot‐Np could be suppressed by infusion of physiologic saline. Levels of OT‐Np were lower in the volume expanded state and were positively correlated with the quantity of sodium excreted into a 24‐hour urine collected after the infusion ( r = 0·426) and inversely correlated with the supine systolic ( r = ‐ 0·379) and supine diastolic ( r = ‐ 0·455) blood pressures recorded after the infusion of saline. Oestrogen, a stimulus to the secretion of OT‐Np, did not account for the elevation of OT‐Np observed in the study, since mean levels of oestradiol (E 2 ) in a subset of the patients with elevated OT‐Np (E 2 = 36 pg/ml) were not different from levels in subjects with lower values of OT‐Np (E 2 = 45 pg/ml). Levels of VP‐Np averaged 0·85 ng/ml and correlated positively with PRA ( r = 0·353) and 24‐hour urine excretion of dopamine ( r = 0·44), and inversely with age ( r = ‐ 0·263), blood pressure, and 24‐hour urine excretion of sodium ( r = ‐ 0·226). Erect posture caused an elevation of VP‐Np. Therefore, levels of OT‐Np and VP‐Np respond to certain physiological stimuli and levels of OT‐Np are elevated in a subgroup of subjects with essential hypertension.