Classification of obese patients and complications related to the distribution of surplus fat

The relation between obesity and noninsulin-dependent diabetes mellitus is established. The weak association between obesity and cardiovascular disease or stroke might be attributable to a risk present only in a subgroup of obesity patients. Recent prospective studies have shown such a group to be characterized by abdominal localization of adipose tissue, reviving old empiric observations of such links. The sex-linked adipose tissue distribution is probably dependent on a balance between glucocorticoids and sex steroid hormones. The former are active mainly on intraabdominal adipose tissues through the high density of a specific receptor expressing lipoprotein lipase activity. This effect is counteracted by female sex steroid hormones, mainly progesterone, which promote fat deposition in the gluteal-femoral regions, utilized mainly during pregnancy and lactation. Testosterone stimulates lipid mobilization through transcriptional expression of beta-adrenergic receptors via a specific androgen receptor and also inhibits lipoprotein lipase activity. Intraabdominal adipose tissues, drained by the portal vein, have a very sensitive lipolytic system in men, based on an increased beta-adrenoceptor activity. This is probably a testosterone effect via the mechanisms mentioned. With testosterone deficiency, these mechanisms are less active, permitting accumulation of fat that can be reversed by testosterone substitution. Abdominal distribution of fat in men thus is probably a sign of relative testosterone deficiency.(ABSTRACT TRUNCATED AT 250 WORDS)