Kidney Tube that Controls Salt Balance Smaller in Women than Men

Rockville, Md. (November 12, 2020)—A long-held belief that the distal convoluted tubule (DCT) in the kidney is bigger in women than men has been disproven, according to a new study published in the American Journal of Physiology-Renal Physiology. Physiologists made the discovery using new 3D microscopic imaging techniques to measure the DCT in mice. The article has been chosen as an APSselect article for November.

 The DCT controls salt balance and blood pressure. It is a highly flexible structure that shrinks and expands to maintain salt balance. Researchers previously thought that the female DCT was bigger because it transports more salt. However, microscopic imaging revealed DCT in men, which number in the thousands, are approximately twice as long as the width of a human hair and are even smaller in women.  

 “We found that the female DCT is surprisingly smaller than the male but has the capacity to grow longer in response to a provoking stimulus,” said Paul Welling, MD, the Joseph S. and Esther Handler Professor at Johns Hopkins University School of Medicine in Baltimore, and the corresponding author of the study.

This research indicates women could be more susceptible to developing resistance to diuretics—drugs that are prescribed to help the body expel more water and salt during urination—under specific conditions. That’s because as the DCT grows in response to the administration of diuretics, the effectiveness of these drugs used to treat high blood pressure, edema and vascular congestion in heart failure weakens.

 Read the full article, “Distal convoluted tubule sexual dimorphism revealed by advanced 3D-imaging,” published in the American Journal of Physiology-Renal Physiology. It is highlighted as one of this month’s “best of the best” as part of the American Physiological Society’s APSselect program. Read all of this month’s selected research articles. 

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