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Estrogen increases renal oxytocin receptor gene expression
N L Ostrowski1, W S Young, S J Lolait
1Laboratory of Cell Biology, National Institute of Mental Health, NIH, Bethesda, MD 20892-4068.
Endocrinology
|April 1, 1995
Summary
Estrogen increases renal oxytocin receptor expression, particularly in proximal tubules, influencing fluid balance. This suggests a key role for these receptors in estrogen-mediated renal fluid dynamics.
Area of Science:
- Endocrinology
- Nephrology
- Molecular Biology
Background:
- Estrogens are linked to fluid and sodium imbalances during the menstrual cycle and pregnancy.
- Renal oxytocin receptors are potential mediators of these estrogen-dependent effects on fluid homeostasis.
Purpose of the Study:
- To investigate the role of estrogens in regulating renal oxytocin receptor expression.
- To determine the specific kidney cells and mechanisms involved in estrogen-induced changes in oxytocin receptor levels.
Main Methods:
- Ovariectomized female rats and adrenalectomized male rats were treated with estradiol benzoate.
- Messenger RNA expression and radioligand binding assays were used to quantify oxytocin receptor levels.
- The effect of tamoxifen, an antiestrogen, on oxytocin receptor expression was assessed.
Main Results:
- Estradiol benzoate treatment significantly increased oxytocin receptor mRNA and binding in the renal cortex and medullary collecting ducts.
- High levels of oxytocin receptor expression were induced in proximal tubules by estradiol.
- Tamoxifen inhibited proximal tubule oxytocin receptor induction but did not affect macula densa cells.
Conclusions:
- Estrogen specifically regulates oxytocin receptor expression in renal macula densa and proximal tubule cells.
- These findings highlight a significant role for renal oxytocin receptors in mediating estrogen's effects on kidney function and fluid balance.