Adipose Tissue Plasticity During Catch-Up Fat Driven by Thrifty Metabolism: Relevance for Muscle-Adipose Glucose Redistribution During Catch-Up Growth

OBJECTIVE: Catch-up growth, a risk factor for later type 2 diabetes, is characterized by hyperinsulinemia, accelerated body-fat recovery (catch-up fat), and enhanced glucose utilization in adipose tissue. Our objective was to characterize the determinants of enhanced glucose utilization in adipose tissue during catch-up fat. RESEARCH DESIGN AND METHODS: White adipose tissue morphometry, lipogenic capacity, fatty acid composition, insulin signaling, in vivo glucose homeostasis, and insulinemic response to glucose were assessed in a rat model of semistarvation-refeeding. This model is characterized by glucose redistribution from skeletal muscle to adipose tissue during catch-up fat that results solely from suppressed thermogenesis (i.e., without hyperphagia). RESULTS: Adipose tissue recovery during the dynamic phase of catch-up fat is accompanied by increased adipocyte number with smaller diameter, increased expression of genes for adipogenesis and de novo lipogenesis, increased fatty acid synthase activity, increased proportion of saturated fatty acids in triglyceride (storage) fraction but not in phospholipid (membrane) fraction, and no impairment in insulin signaling. Furthermore, it is shown that hyperinsulinemia and enhanced adipose tissue de novo lipogenesis occur concomitantly and are very early events in catch-up fat. CONCLUSIONS: These findings suggest that increased adipose tissue insulin stimulation and consequential increase in intracellular glucose flux play an important role in initiating catch-up fat. Once activated, the machinery for lipogenesis and adipogenesis contribute to sustain an increased insulin-stimulated glucose flux toward fat storage. Such adipose tissue plasticity could play an active role in the thrifty metabolism that underlies glucose redistribution from skeletal muscle to adipose tissue

A glucomannan from the tubers of Orchis morio

A glucomannan containing d-glucopyranosyl and d-mannopyranosyl residues in the molar ratio ca 1:3·3 has been extracted with water from the tubers of Orchis morio. The polysaccharide has a View the MathML sourcen of ca 665 and consists of a backbone of β(1 → 4)- linked glucosyl and mannosyl residues with ca. 7 branch points per molecule, probably at C3 positions of the hexose residues. The polysaccharide contains acetyl groups linked almost exclusively to the C2 or C3 positions of mannose residues. Structural studies showed that this water-extracted glucomannan is similar to the material of the mucilage globules which had been mechanically separated and isolated from the tissue of young tubers