According to Fick's principle, any metabolic or hormonal exchange through a given tissue depends on the product of the blood flow to that tissue and the arteriovenous difference. The proper function of adipose tissue relies on adequate adipose tissue blood flow (ATBF), which determines the influx and efflux of metabolites as well as regulatory endocrine signals. Adequate functioning of adipose tissue in intermediary metabolism requires finely tuned perfusion. Because metabolic and vascular processes are so tightly interconnected, any disruption in one will necessarily impact the other. Although altered ATBF is one consequence of expanding fat tissue, it may also aggravate the negative impacts of obesity on the body's metabolic milieu. This review attempts to summarize the current state of knowledge on adipose tissue vascular bed behavior under physiological conditions and the various factors that contribute to its regulation as well as the possible participation of altered ATBF in the pathophysiology of metabolic syndrome. obesity; insulin; sympathetic nervous system; nitric oxide; angiotensin II; atrial natriuretic peptide; glucagon-like peptide-1; glucose-dependent insulinotropic polypeptide OVER THE LAST DECADES, THE WORLDWIDE PANDEMIC of obesity, metabolic syndrome, and type 2 diabetes mellitus (T2DM) (188) has attracted ever-increasing attention to the role and significance of adipose tissue (AT). Originally regarded as a mere energy store with insulation and protective cushioning functions, AT is now recognized as a bona fide and highly active metabolic and endocrine organ (102). It has also become evident that the white AT is a heterogeneous tissue. From a metabolic point of view, AT can be subdivided into central (abdominal) and peripheral (hips and buttocks) depots (78). Although extra-abdominal fat accumulation does not bring upon higher metabolic and cardiovascular risk, some reports show a protective influence (124). Conversely, a negative metabolic effect has been associated with central fat (102), which in fact comprises two distinct masses (visceral and subcutaneous) with different metabolic and hormonal activities and impacts on metabolic syndrome pathogenesis (95) and blood flow rates (102).Metabolic processes in fatty tissue require adequate substrate(s) and humoral factor delivery (76). Conversely, adipocytes communicate with other metabolically active tissues through humoral factors (128) as well as through metabolic products (118) serving as energetic substrates. Humoral factors derived from AT arise not only from adipocytes themselves but also from other components of AT such as macrophages and endothelial cells. Moreover, AT is a known conversion site for several hormones or humoral factors, e.g., steroid hormones (156) or components of the renin-angiotensin-aldosterone system (RAAS). All of these functions of AT are tightly linked to the pattern of blood supply and its regulation, which largely differ from other metabolically active organs such as the liver or skeletal muscle (141).In add...

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Langin D, Stich V. The atrial natriuretic peptide-and catecholamineinduced lipolysis and expression of related genes in adipose tissue in hypothyroid and hyperthyroid patients.

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