Down-regulation of urinary AQP2 and unaffected response to hypertonic saline after 24 hours of fasting in humans
| Autor: | Jesper N. Bech, J. Starklint, Erling B. Pedersen |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Adult
Male medicine.medical_specialty Vasopressin Urinary system medicine.medical_treatment Down-Regulation urologic and male genital diseases Aquaporins Atrial natriuretic peptide Internal medicine urinary concentrating ability Natriuretic Peptide Brain Renin medicine Humans healthy humans Saline Aldosterone Saline Solution Hypertonic Aquaporin 2 Cross-Over Studies business.industry urogenital system Angiotensin II clinical trial Fasting Middle Aged Hypertonic saline Free water clearance Endocrinology Nephrology Urine osmolality vasopressin V2 receptors Female business Atrial Natriuretic Factor Antidiuretic |
| Zdroj: | Starklint, J, Bech, J N & Pedersen, E B 2005, ' Down-regulation of urinary AQP2 and unaffected response to hypertonic saline after 24 hours of fasting in humans ', Kidney International, vol. 67, no. 3, pp. 1010-18 . https://doi.org/10.1111/j.1523-1755.2005.00164.x |
| ISSN: | 0085-2538 |
| DOI: | 10.1111/j.1523-1755.2005.00164.x |
| Popis: | Down-regulation of urinary AQP2 and unaffected response to hypertonic saline after 24 hours of fasting in humans.BackgroundIn rats, 24 hours of fasting impairs urinary concentrating ability by down-regulation of aquaporin-2 (AQP2). We tested the hypothesis that 24 hours of fasting in humans reduces the capability to form AQP2 and impairs the antidiuretic response to hypertonic saline infusion.MethodsIn a crossover study of 14 healthy subjects, the effect of 24 hours of fasting was compared to a nonfasting control experiment on urinary excretion of AQP2 (u-AQP2), free water clearance (CH2O), plasma arginine vasopressin (AVP), urinary cyclic AMP (u-cAMP), and natriuretic peptides. The following response to 3% sodium infusion was measured using the same effect variables. U-AQP2, AVP, and u-cAMP were determined by radioimmunoassays.ResultsFasting during 24 hours reduced u-AQP2 (14%), increased AVP (30%) despite a reduction in serum osmolality (P < 0.05), and depleted volume. CH2O and urine volume were not reduced, thus relatively increased after fasting. u-cAMP was not significantly different between the two procedures. Three percent saline resulted in the same relative increases in AVP, serum osmolality, u-AQP2, and u-cAMP and decreases in CH2O and urine volume independently of fasting. The reduced u-AQP2 and increased AVP after fasting were maintained during and after saline infusion.ConclusionTwenty-four hours of fasting decreased u-AQP2 and reduced urine osmolality likely as a result of decreased sensitivity of collecting duct cells to AVP. Fasting-related insensitivity of collecting duct cells to AVP was restored by 3% saline infusion. Finallly, after saline infusion, other factors such as the increased plasma atrial natriuretic peptide (p-ANP) levels could contribute to the u-AQP2 regulation. |
| Databáze: | OpenAIRE |
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