Depot-specific differences in adipocyte insulin sensitivity in mice are diet- and function-dependent.

Area of Science:

• Metabolic research
• Adipocyte biology
• Endocrinology

Background:

• Different fat depots exhibit distinct metabolic functions.
• Previous studies showed varied lipolysis regulation in perigonadal vs. mesenteric adipocytes.
• Insulin's anti-lipolytic effect differs between these depots, especially under high-fat diet (HFD).

Purpose of the Study:

• To investigate insulin sensitivity in inguinal (subcutaneous) adipocytes.
• To compare insulin's effects on lipolysis and glucose metabolism across perigonadal, mesenteric, and inguinal fat depots.
• To determine the influence of diet and depot location on adipocyte insulin sensitivity.

Main Methods:

• Analysis of lipolysis and glucose incorporation in isolated adipocytes.
• Comparison of perigonadal, mesenteric, and inguinal adipocytes from mice on chow or high-fat diets (HFD).

Main Results:

• Inguinal adipocytes show similar insulin sensitivity to perigonadal adipocytes under normal diet.
• Inguinal adipocytes retain insulin sensitivity under HFD, unlike perigonadal adipocytes.
• Insulin-stimulated glucose incorporation is reduced in all three depots under HFD.
• Mesenteric adipocytes maintain insulin's anti-lipolytic effect under HFD.

Conclusions:

• Adipocyte insulin sensitivity is regulated by diet, fat depot location, and specific metabolic functions.
• Perigonadal adipocytes lose insulin sensitivity under HFD, while mesenteric and inguinal adipocytes maintain it.
• These findings highlight depot-specific adaptations in metabolic regulation.