When male mice are genetically changed so their kidney cells can't respond to insulin, they lose less salt in their urine when given a certain drug, have lower levels of a salt-handling protein, and have lower blood pressure — which might mean insulin helps control blood pressure through the kidneys.

What we've found so far suggests that insulin signaling in kidney cells may play a role in blood pressure regulation and sodium handling in male mice. Our analysis of the available evidence shows that when insulin receptors are deleted in kidney cells, changes occur in how the body handles salt and blood pressure. We reviewed one key assertion based on studies in male mice [1]. In these mice, removing the insulin receptor from kidney cells led to lower blood pressure. These mice also excreted less sodium in their urine when given a drug that normally increases sodium loss, suggesting their kidneys were retaining more salt. Along with this, levels of a protein involved in moving sodium in the kidneys were reduced [1]. Since sodium balance affects blood pressure, these findings suggest that insulin’s action in the kidney might help regulate both sodium handling and blood pressure. The evidence we've reviewed leans toward the idea that insulin signaling in kidney cells influences how the body manages salt and blood pressure in male mice. However, we only have one analyzed assertion based on a single line of research. While 13.0 supporting studies are cited in that assertion, we have not reviewed the individual studies ourselves and are relying on the reported summary. There are no studies in our current analysis that contradict this finding. Our current analysis does not allow us to draw firm conclusions about how or how strongly this mechanism works, or whether it applies beyond male mice. We cannot say whether this effect is direct or involves other systems. Also, we don’t know if similar effects would occur in females or other species, including humans. Practical takeaway: In male mice, turning off insulin response in kidney cells seems linked to lower blood pressure and changes in salt handling — but we need more evidence to understand what this really means for long-term health or human conditions.