Abstract
To assess the influence of late hyponatraemia on the renal responsiveness to endogenous arginine vasopressin (AVP), urinary excretion and plasma concentration of sodium, plasma and urine osmolality, free water clearance, and urinary AVP concentration and excretion were measured in 11 healthy premature infants with a mean birth weight of 1360 g and mean gestational age of 31 weeks. Studies were performed on days 1, 5, and 19. The development of late hyponatraemia was associated with a pronounced decline in urine osmolality, whereas urine flow rate and free water clearance increased significantly. Mean (SEM) urine AVP concentration and excretion also rose significantly from 2.15 (0.31) pg/ml and 0.36 (0.55) pg/min/m2 on the first day to 6.5 (0.96) pg/ml and 3.85 (0.63) pg/min/m2 on the 19th day, respectively. When renal response to AVP was compared at different ages the highest urine osmolality and steepest response curve was observed on the first day. With development of hyponatraemia the renal response became blunted. It is concluded that the limited tubular sodium transport and hyponatraemia hinders the establishment of intrarenal osmotic gradient, impairs renal response to AVP, and prevents excessive water retention and further fall of plasma sodium.
Full text
PDF
Selected References
These references are in PubMed. This may not be the complete list of references from this article.
- Burg M. B., Green N. Function of the thick ascending limb of Henle's loop. Am J Physiol. 1973 Mar;224(3):659–668. doi: 10.1152/ajplegacy.1973.224.3.659. [DOI] [PubMed] [Google Scholar]
- EDELMANN C. M., BARNETT H. L., TROUPKOU V. Renal concentrating mechanisms in newborn infants. Effect of dietary protein and water content, role of urea, and responsiveness to antidiuretic hormone. J Clin Invest. 1960 Jul;39:1062–1069. doi: 10.1172/JCI104121. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Heinegård D., Tiderström G. Determination of serum creatinine by a direct colorimetric method. Clin Chim Acta. 1973 Feb 12;43(3):305–310. doi: 10.1016/0009-8981(73)90466-x. [DOI] [PubMed] [Google Scholar]
- Kokko J. P., Rector F. C., Jr Countercurrent multiplication system without active transport in inner medulla. Kidney Int. 1972 Oct;2(4):214–223. doi: 10.1038/ki.1972.97. [DOI] [PubMed] [Google Scholar]
- Marsh D. J., Segel L. A. Analysis of countercurrent diffusion exchange in blood vessels of the renal medulla. Am J Physiol. 1971 Sep;221(3):817–828. doi: 10.1152/ajplegacy.1971.221.3.817. [DOI] [PubMed] [Google Scholar]
- Rees L., Brook C. G., Shaw J. C., Forsling M. L. Hyponatraemia in the first week of life in preterm infants. Part I. Arginine vasopressin secretion. Arch Dis Child. 1984 May;59(5):414–422. doi: 10.1136/adc.59.5.414. [DOI] [PMC free article] [PubMed] [Google Scholar]
- Srámková J., Horký K., Dvoráková J. Radioimmunoassay of arginine vasopressin in the plasma and urine. Physiol Bohemoslov. 1979;28(5):399–409. [PubMed] [Google Scholar]
- Sulyok E., Ertl T., Csaba I. F., Varga F. Postnatal changes in urinary prostaglandin E excretion in premature infants. Biol Neonate. 1980;37(3-4):192–196. doi: 10.1159/000241273. [DOI] [PubMed] [Google Scholar]
- Sulyok E., Kovács L., Lichardus B., Michajlovskij N., Lehotska V., Némethova V., Varga L., Ertl T. Late hyponatremia in premature infants: role of aldosterone and arginine vasopressin. J Pediatr. 1985 Jun;106(6):990–994. doi: 10.1016/s0022-3476(85)80256-0. [DOI] [PubMed] [Google Scholar]
- Svenningsen N. W., Aronson A. S. Postnatal development of renal concentration capacity as estimated by DDAVP-test in normal and asphyxiated neonates. Biol Neonate. 1974;25(3-4):230–241. doi: 10.1159/000240695. [DOI] [PubMed] [Google Scholar]