Ectopic lipid storage in muscle in the form of intramyocellular lipids (IMCL) and liver as hepatocellular lipids (HCL) concurs with altered myocellular flux through ATP synthase (fATPase) in some women with increased risk of type 2 diabetes. It has been observed that women with a history of gestational diabetes mellitus (pGDM) have increased risk of ectopic lipids and diabetes, thus, the authors investigated whether deteriorated energy metabolism plays an important role in these abnormalities.

The study enrolled a total of 23 glucose-tolerant nonobese pGDM and eight women with normal glucose metabolism during pregnancy with similar age, body mass, and physical activity. All these women underwent oral glucose tolerance tests (OGTT) and intravenous glucose tolerance tests at 4-5 years after delivery. OGTT values <463 mL⋅ min(-1)⋅m(-2) were suggestive of insulin resistance. pGDM were further categorized into insulin-resistant (pGDM-IR) and insulin-sensitive (pGDM-IS) groups. IMCL, HCL, and fATPase were determined with (1)H/(31)P magnetic resonance spectroscopy.

The outcome revealed that pGDM had 36% higher fat mass and 12% lower insulin sensitivity. Log-transformed fATPase was lesser in pGDM [10.6 ± 3.8 µmol⋅mL muscle(-1)⋅min(-1) vs. 12.1 ± 1.4 µmol⋅mL muscle(-1)⋅min(-1)] and associated with plasma adiponectin, after adjusting body fat. IMCL were higher in pGDM-IR (61%) and insulin resistant women (69%). HCL were doubled in pGDM and insulin resistant women, and was positively related to body fat mass whereas inversely associated with insulin sensitivity.

The findings thus, concluded that glucose-tolerant pGDM exhibited increased liver fat with marginal lower muscular insulin sensitivity and ATP synthesis. These results indicates that impaired hepatic lipid storage is an early and major abnormality in women who had gestational diabetes mellitus.

Source: Prikoszovich T, Winzer C, Schmid AI, Szendroedi J, Chmelik M, Pacini G, Krssák M, Moser E, Funahashi T, Waldhäusl W, Kautzky-Willer A, Roden M. Body and liver fat mass rather than muscle mitochondrial function determine glucose metabolism in women with a history of gestational diabetes mellitus. Diabetes Care. 2011 Feb;34(2):430-6.