Heat stress increases insulin sensitivity in pigs

Area of Science:

• Animal Physiology
• Metabolic Regulation
• Environmental Stressors

Background:

• Insulin homeostasis is crucial for adapting to heat load.
• Heat stress (HS) in livestock induces phenotypic changes suggesting increased insulin action.

Purpose of the Study:

• To evaluate the effects of heat stress on whole-body insulin sensitivity in pigs.
• To investigate molecular changes in skeletal muscle and adipose tissue related to insulin signaling under heat stress.

Main Methods:

• Utilized a hyperinsulinemic euglycemic clamp (HEC) to assess insulin sensitivity.
• Administered an insulin tolerance test (ITT) and collected tissue biopsies.
• Compared pigs under constant heat stress (32°C) with pair-fed thermoneutral controls.

Main Results:

• Heat stress maintained glucose infusion rates during HEC, unlike controls which decreased by 36%.
• Skeletal muscle insulin receptor substrate-1 protein increased by 41% under HS.
• No significant changes in adipose tissue insulin signaling markers were observed.

Conclusions:

• Heat stress enhances whole-body insulin-stimulated glucose uptake in pigs.
• Metabolic adaptations to heat stress involve increased insulin sensitivity, particularly in skeletal muscle.
• Findings contribute to understanding livestock adaptation to thermal environments.