# Mechanisms and Consequences of Defective Flow-Induced Potassium Secretion in the Metabolic Syndrome

> **NIH NIH R01** · STANFORD UNIVERSITY · 2021 · $415,548

## Abstract

PROJECT SUMMARY / ABSTRACT: The metabolic syndrome affects 50 million Americans, and is associated
with obesity and insulin resistance. Hyperkalemia is associated with life-threatening cardiac arrhythmias and
increased mortality, and patients with insulin resistance and Type 2 diabetes are susceptible to hyperkalemia.
However, potential derangements in renal potassium (K) handling remain unexplored. As part of our ongoing
NIH-sponsored studies of ion channel function in insulin resistance, we, the Investigators (PI and Co-I),
uncovered that flow-induced K secretion (FIKS) in the distal nephron, mediated by BK channels, and renal K
handling is defective. Deletion of BK channels leads to defective renal K handling, and impaired K adaptation.
The objective of this proposal is to determine the mechanisms underlying the reduction in BK channel-
mediated FIKS in the distal nephron and to determine the consequences for K adaptation and hyperkalemia in
the insulin resistance syndrome. The R01 Grant will provide the necessary resources to test the hypothesis
that insulin resistance in the distal nephron is a phenocopy for BK channel deficiency with decreased insulin
signaling leading to disrupted BK channel activity, and thus, defective FIKS and K adaptation, and
predisposition to hyperkalemia. To test this hypothesis, we propose two specific aims. Aim #1 is to determine
the cellular mechanisms of distal nephron BK channel dysfunction in a mouse model of insulin resistance.
Using control and insulin resistant mice, we will measure expression and subcellular localization of distal
nephron BK and Ca2+- channels using two innovative methodologies, and will study the Ca2+ and voltage
sensitivity of BK channels. We will also measure the impact of defective BK channels on K adaptation and
hyperkalemia in the metabolic syndrome. Aim #2 is to determine whether impaired insulin receptor signaling in
the distal nephron is sufficient to phenocopy the BK channel dysfunction of insulin resistance. Using a novel
renal tubular insulin receptor knockout mouse, we will measure BK and Ca2+ channel expression, and
subcellular localization using similar methods to Aim #1. We will study the Ca2+ and voltage sensitivity of BK
channels in control and knockout mice and will measure the effect of deletion of insulin receptor signaling on K
adaptation and hyperkalemia. We will also measure cell signaling pathways related to insulin and BK channels.
We anticipate that these results will significantly advance the field by identifying appropriate dietary and
pharmaceutical targets for the prevention and treatment of hyperkalemia in diseases associated with insulin
resistance, such as obesity and Type 2 diabetes mellitus. The proposed research is innovative in that we will
directly study the regulation of renal BK channels in insulin resistance and will employ novel reagents and
cutting-edge techniques to understand the consequences of defective FIKS for hyperkalemia. Through the
prop...

## Key facts

- **NIH application ID:** 10202571
- **Project number:** 5R01DK115770-04
- **Recipient organization:** STANFORD UNIVERSITY
- **Principal Investigator:** VIVEK BHALLA
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2021
- **Award amount:** $415,548
- **Award type:** 5
- **Project period:** 2018-09-15 → 2022-12-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10202571

## Citation

> US National Institutes of Health, RePORTER application 10202571, Mechanisms and Consequences of Defective Flow-Induced Potassium Secretion in the Metabolic Syndrome (5R01DK115770-04). Retrieved via AI Analytics 2026-05-25 from https://api.ai-analytics.org/grant/nih/10202571. Licensed CC0.

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