Acute hyperinsulinemia inhibits intramyocellular triglyceride synthesis in high-fat-fed obese rats

ZengKui Guo, Lianzhen Zhou, Michael Dennis Jensen

Research output: Contribution to journalArticle

9 Citations (Scopus)

Abstract

Hyperinsulinemia is common in obesity, but whether it plays a role in intramyocellular triglyceride (imcTG) buildup is unknown. In this study, hyperinsulinemic-euglycemic clamp experiments were performed in overnight-fasted lean and high-fat-fed obese rats, awake, to determine the effect of insulin on imcTG synthesis (incorporation of [14C]glycerol, [ 14C]glucose, and [3H]oleate). Insulin infusion at 25 (low insulin) and 100 (high insulin) pmol/kg/min increased plasma insulin by 5- and 16-fold, respectively, whereas plasma and intramyocellular glycerol, FFAs, triglycerides, and glucose levels were maintained at their basal levels by co-infusion of exogenous glycerol, FFAs, and triglycerides at fixed rates and glucose at varying rates. In obese rats, insulin suppressed incorporation of glycerol into the imcTG-glycerol moiety dose dependently (P < 0.01-P < 0.001) in gastrocnemius and tibialis anterior, but only the high insulin suppressed it in soleus (P < 0.05). The low insulin suppressed glucose incorporation into imcTG-glycerol in all three muscles (P = 0.01-P < 0.01). However, the low insulin did not affect (P > 0.05) and the high insulin suppressed (P < 0.05-P < 0.01) fatty acid incorporation into imcTG in all three muscles. Insulin also suppressed glycerol incorporation in lean rats (P < 0.01-P < 0.04). On the other hand, imcTG pool size was not affected by insulin (P > 0.05). These observations suggest that acute hyperinsulinemia inhibits imcTG synthesis and thus does not appear to promote imcTG accumulation via the synthetic pathway, at least in the short term.

Original languageEnglish (US)
Pages (from-to)2640-2646
Number of pages7
JournalJournal of Lipid Research
Volume47
Issue number12
DOIs
StatePublished - Dec 2006

Fingerprint

Hyperinsulinism
Rats
Triglycerides
Fats
Insulin
Glycerol
Glucose
Plasmas
Glucose Clamp Technique
Clamping devices
Oleic Acid
Obesity

Keywords

  • Insulin
  • Muscle
  • Obesity
  • Triglycerides

ASJC Scopus subject areas

  • Endocrinology

Cite this

Acute hyperinsulinemia inhibits intramyocellular triglyceride synthesis in high-fat-fed obese rats. / Guo, ZengKui; Zhou, Lianzhen; Jensen, Michael Dennis.

In: Journal of Lipid Research, Vol. 47, No. 12, 12.2006, p. 2640-2646.

Research output: Contribution to journalArticle

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