Gender differences in the effect of antenatal Betamethasone (Beta) exposure on NHE3 mRNA expression in ovine renal proximal tubule cells from young adult sheep

Program: Abstracts - Orals, Featured Poster Presentations, and Posters
Session: MON 723-757-Renin-Angiotensin-Aldosterone System/Endocrine Hypertension
Bench to Bedside
Monday, June 17, 2013: 1:45 PM-3:45 PM
Expo Halls ABC (Moscone Center)

Poster Board MON-756
Yixin Su*1, Jianli Bi2 and Jorge P Figueroa2
1Wake Forest Univ Hlth Sci, Winston Salem, NC, 2Wake Forest University Health Science, Winston-Salem, NC
Objective: Exposure of the fetus to elevated glucocorticoids during critical periods of gestation  results in the development of elevated blood pressure in the adult offspring. We have shown that renal proximal tubule cells (RPTC) from male offspring exposed to Beta during gestation have   increased Na+ uptake while cells from females do not. One system that could serve as a mechanism for sodium uptake is Na+/H+ exchanger 3(NHE3) which is found in  nephrons. This study was compares the consequences of antenatal Beta exposure on postnatal expression the NHE3 mRNA in ovine RPTC from adult male and female sheep.

Materials and Methods: Male and female sheep were administered betamethasone (2 doses of 0.17 mg/kg, 24 hours apart) or vehicle at the 80th day of gestation and delivered at term. Kidney cortex was obtained from animals at one year of age and proximal tubule cells were cultured for 7-10 days. The confluent monolayers of the cells were incubated with or without Angintensin II (10−11 M). Cells from basal or AngII-stimulation were then harvested for RNA extraction and relative mRNA expression of NHE3 was measured by Real time PCR. Data were analyzed by analysis of variance.

Results: Prenatal steroid exposure increased NHE3 mRNA expression from renal proximal tubule cells only in male sheep compared with vehicle treatment (F=4.33; P<0.05). There was no significant difference in NHE3 mRNA expression in female sheep exposed to Beta. Following AngII stimulation, there was a trend that NHE3 mRNA expression was increased in RPTC from male but not female sheep.

Conclusions: These data suggest that prenatal Beta increases Na+ uptake by RPTC in male sheep may be linked to increased NHE3 expression in proximal tubule cells from male sheep. Thus, there are gender related differences in the effects of antenatal Beta exposure on genes related to Na transport in the kidney.

Nothing to Disclose: YS, JB, JPF

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Sources of Research Support: Supported by NIH grants 17644 and 47584