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Urinary concentration does not exclusively rely on plasma vasopressin. A study between genders Gender and diurnal urine regulation
Author(s) -
GraugaardJensen C.,
Hvistendahl G. M.,
Frøkiær J.,
Bie P.,
Djurhuus J. C.
Publication year - 2014
Publication title -
acta physiologica
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.591
H-Index - 116
eISSN - 1748-1716
pISSN - 1748-1708
DOI - 10.1111/apha.12337
Subject(s) - vasopressin , medicine , urine osmolality , endocrinology , urine , oxytocin , plasma osmolality , excretion , circadian rhythm , reabsorption , urinary system , diuresis , kidney
Aim We investigated the influence of gender on the diurnal regulation of urine production with special focus on vasopressin, oxytocin and prostaglandin E2. Methods Fifteen young women in mid‐follicular phase and 22 young men (20–33 years) were included. All participants underwent a 24‐h circadian inpatient study under standardized conditions for measurements of plasma vasopressin, oxytocin, sodium and osmolality. Urine was fractionally collected for measurements of electrolytes, aquaporin‐2 and prostaglandin E2. Results Plasma vasopressin expressed a diurnal rhythm with a night‐time increase in both genders ( P < 0.001). The ratio between mean daytime and mean night‐time was 1.57 [95% CI: 1.33–1.84] P < 0.001 in men and 1.35 [95% CI: 1.11–1.64] P = 0.002 in women. P‐vasopressin was higher in males during the night ( P < 0.05). There was no difference in diuresis ( P = 0.43), urine osmolality ( P = 0.12) or aquaporin‐2 excretion ( P = 0.80) between genders. We found a trend towards a higher reabsorption of free water in males ( P = 0.07). The excretion of prostaglandin E2 was higher in males ( P < 0.001). There was no diurnal rhythm in p‐oxytocin ( P = 0.37) and no correlation to diuresis, urine osmolality or aquaporin‐2 excretions. Conclusion Similar urinary flows and osmolalities are associated with levels of plasma vasopressin and renal PGE 2, which are higher in males than in females. Oxytocin does not seem to play a role in the diurnal urine formation, whereas prostaglandin E2 could represent a mediator of the gender difference, not only as a mediator of the vasopressin response, but also as an independent factor. These findings need further elucidation.