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Disturbance of osmoregulated thirst and vasopressin secretion in thyrotoxicosis
Author(s) -
Harvey J. N.,
Nagl D. K.,
Baylis P. H.,
Wllkinsont R.,
Belchetz P. E.
Publication year - 1991
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.1365-2265.1991.tb03492.x
Subject(s) - thirst , plasma osmolality , medicine , endocrinology , vasopressin , hypertonic saline , plasma renin activity , homeostasis , sed , tonicity , euthyroid , chemistry , thyroid , renin–angiotensin system , blood pressure
Summary.objective To assess the effect of untreated thyrotoxicosis on osmoregulated thirst sensation and AVP secretion. design Measurements were made at 30‐minute Intervals while untreated thyrotoxic patients were given sodium chloride 855 mmol/l Intravenously for 2 hours followed by water drinking adlibitum for 2 hours. The protocol was repeated when the patients were euthyroid. patients Eight newly diagnosed thyrotoxic patients were studied. measurements Thirst sensation (visual analogue scale), plasma osmolality, AVP and plasma renin activity were measured. results Prior to osmotic stimulation and after plasma osmolality had been returned to normal by drinking water, thirst sensation was Increased in the thyrotoxic state. Plasma AVP showed an exaggerated response to hypertonic saline in the patients when they were thyrotoxic. Increasing plasma osmolality produced a linear Increase in thirst sensation and log linear increase in plasma AVP. However, in the thyrotoxic state both these relations were altered. The apparent osmolar thresholds for onset of thirst sensation and AVP release were similar (281 and 280 mosm/kg respectively) and were reduced similarly In the thyrotoxic state (269 and 274 mosm/kg respectively). conclusions The osmostat mechanisms which regulate thirst sensation and AVP release are reset In the thyrotoxic state. The responses of thirst sensation and of plasma AVP to increasing plasma osmolality are altered similarly, suggesting that thyrotoxicosls affects both homeostatic functions by a common mechanism.