Influence of sex on aquaporin1–4 and vasopressin V2 receptor expression in the pig kidney during development

Abstract

Background:The ability of the immature kidney to concentrate urine is lower than in adults. The aquaporin (AQP) family and the vasopressin V2 receptor (V2R) play a critical role in the urinary concentrating capacity. Here we investigated a possible sex difference in AQP1, AQP2, AQP3, and AQP4 as well as V2R expression in the fetal pig kidney at different gestation stages. Methods: Pig fetuses were divided into three groups according to gestation age of 60, 80, and 100 d. Quantitative PCR and immunohistochemistry were used to determine the regulation of AQP1, AQP2, AQP3, and AQP4 as well as V2R in the fetal pig kidneys. results: Renal AQP1, AQP2 and AQP3, and V2R expression was increased with gestation age in both sexes, whereas AQP4 expression was unchanged over time. We observed neither sex differences in the AQPs nor V2R expression in the fetal pig kidneys. conclusion: AQP1, AQP2, and AQP3, and V2R expression increased with gestation age in the fetal kidney, suggesting that this induction might contribute to the maturation of urinary concentrating capacity. However, no sex differences were observed indicating that sex might not play a role for the maturation of the urinary concentrating activity during kidney development in fetal pig.

Urinalysis in Great Dane Puppies from Birth to 28 Days of Age

“…The absence of gender effects on the oscillation of urinary parameters is in agreement with the data reported on pigs, in which aquaporin 1-4 and vasopressin V2 receptor expression in the fetal and neonatal kidney during development were not influenced by the gender [42].…”

Role of the renin–angiotensin system in kidney development and programming of adult blood pressure

“…In rats, immature vasa recta bundles appear at approximately P10 and in humans in late second trimester (gestational age 27-28) followed by a gradual maturation and expansion of bundle size [94]. Full differentiation of the different nephron segments is acquired in the third postnatal week in rat through increased expression of the Na-K-ATPase [95], sodium-potassium-2 chloride cotransporter (NKCC-2) [46], aquaporin-2 (AQP-2) [96], vasopressin V2 receptor [97] and urea transporters [98] facilitating normal sodium handling and full urinary concentration capacity. Lack of an inner medulla, likely through aplasia, is part of the developmental phenotype seen after ACE inhibition and after AT 1 blocker treatment where the inner medulla but not the outer medullary volume is reduced in rat by 50% [99].…”

Physiological aspects of pig kidney xenotransplantation and implications for management following transplant

“…40 Aquaporin and ADH 2 receptor expression increase with fetal age resulting in the increased urinary concentration capabilities of older pigs which may help determine the optimal age at which pig kidneys should be transplanted. 41 ADH also serves to increase the concentration of urea and sodium in the renal medulla by increasing the expression of urea transporters…”

“…When infused into pigs, arginine ADH increases renal blood flow 40 . Aquaporin and ADH 2 receptor expression increase with fetal age resulting in the increased urinary concentration capabilities of older pigs which may help determine the optimal age at which pig kidneys should be transplanted 41 …”