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The normal increase in insulin after a meal may be required to prevent postprandial renal sodium and volume losses. Am J Physiol Regul Integr Comp Physiol 2017 Jun 01;312(6):R965-R972

Date

03/24/2017

Pubmed ID

28330966

Pubmed Central ID

PMC5495919

DOI

10.1152/ajpregu.00354.2016

Scopus ID

2-s2.0-85020443101 (requires institutional sign-in at Scopus site)   9 Citations

Abstract

Despite the effects of insulinopenia in type 1 diabetes and evidence that insulin stimulates multiple renal sodium transporters, it is not known whether normal variation in plasma insulin regulates sodium homeostasis physiologically. This study tested whether the normal postprandial increase in plasma insulin significantly attenuates renal sodium and volume losses. Rats were instrumented with chronic artery and vein catheters, housed in metabolic cages, and connected to hydraulic swivels. Measurements of urine volume and sodium excretion (UNaV) over 24 h and the 4-h postprandial period were made in control (C) rats and insulin-clamped (IC) rats in which the postprandial increase in insulin was prevented. Twenty-four-hour urine volume (36 ± 3 vs. 15 ± 2 ml/day) and UNaV (3.0 ± 0.2 vs. 2.5 ± 0.2 mmol/day) were greater in the IC compared with C rats, respectively. Four hours after rats were given a gel meal, blood glucose and urine volume were greater in IC rats, but UNaV decreased. To simulate a meal while controlling blood glucose, C and IC rats received a glucose bolus that yielded peak increases in blood glucose that were not different between groups. Urine volume (9.7 ± 0.7 vs. 6.0 ± 0.8 ml/4 h) and UNaV (0.50 ± 0.08 vs. 0.20 ± 0.06 mmol/4 h) were greater in the IC vs. C rats, respectively, over the 4-h test. These data demonstrate that the normal increase in circulating insulin in response to hyperglycemia may be required to prevent excessive renal sodium and volume losses and suggest that insulin may be a physiological regulator of sodium balance.

Author List

Irsik DL, Blazer-Yost BL, Staruschenko A, Brands MW

MESH terms used to index this publication - Major topics in bold

Animals
Biomarkers
Blood Glucose
Glucose Clamp Technique
Hyperglycemia
Insulin
Kidney
Male
Models, Animal
Natriuresis
Postprandial Period
Rats, Sprague-Dawley
Renal Elimination
Sodium
Time Factors
Up-Regulation
Urination