Multiple skin tags appear associated with abnormalities in glucose/insulin metabolism. Clinical and metabolic glucose/insulin characteristics of men with multiple (8 or more) skin tags on the neck were compared with a control group with few or none. Both groups were divided in two subgroups according to normal or abnormal laboratory findings. In the study subgroup with normal laboratory findings the number of skin tags varied from 8-33, whereas in those with abnormal laboratory findings the range was 9-65. Eight or more skin tags were related with statistically significant laboratory glucose/insulin abnormalities: basal hyperinsulinemia (p<0.002), postprandial hyperinsulinemia (p<0.003), and postprandial hyperglycemia (p<0.01). In the multiple skin tag group 77 % had diverse laboratory abnormalities, including insulin resistance, basal hyperinsulinemia, postprandial hyperinsulinemia, glucose intolerance or type 2 diabetes, in contrast with the control group, where only 33 % showed laboratory abnormalities. One-third of the study group had acanthosis nigricans. Only 15 % of patients with metabolic abnormalities did not show any cutaneous expression of glucose/insulin alterations (9 or more skin tags on the neck, acanthosis nigricans, or waist circumference greater than 95 cm). Multiple skin tags were more sensitive than acanthosis nigricans in identifying those with alterations in the glucose/insulin metabolism (77 vs. 32 % respectively), although less specific (68 vs.100%). Multiple skin tags should raise suspicion of insulin resistance or hyperinsulinemia.

Plasma and urinary levels of thiobarbituric acid reactive substances (TBAR) were determined in 24 hyperthyroid patients, 19 hypothyroid subjects, 35 controls, and 17 hyperthyroid patients before and after propylthiouracil (PTU) treatment (400 mg/day for 2-3 months), as indexes of lipid peroxidation. These measurements were carried out together with t-butyl hydroperoxide (t-BHP)-induced oxygen uptake and visible chemiluminescence in erythrocytes as functional tests related to the antioxigenic capacity of cells. Hyperthyroid patients exhibited increased levels of plasma and urinary TBAR compared to controls. Erythrocyte suspensions from hyperthyroid patients showed, compared to controls, higher rates of oxygen consumption with shorter induction periods upon addition of t-BHP, together with 142% and 75% increases in basal and t-BHP-induced chemiluminescence, respectively. Levels of TBAR in untreated hyperthyroid patients in plasma (16.2 +/- 1.3 pmol/mg of protein) and urine (15.9 +/- 1.5 nmol/mg of creatinine) were decreased after PTU treatment (Plasma, 9.5 +/- 0.7, p less than 10(-4); urine, 7.8 +/- 0.9, P less than 10(-5) to values not significantly different from those of the control group (plasma, 10.3 +/- 0.6; urine, 7.9 +/- 0.7). Compared to control, elevated rates of oxygen uptake induced by t-BHP, basal and t-BHP-induced chemiluminescence in erythrocyte suspensions from untreated hyperthyroid patients were reverted to normal by PTU, while decreased induction period (T0) values were enhanced. Determination of these lipid peroxidative parameters in hypothyroid patients revealed no significant changes over control values, excepted t-BHP-induced chemiluminescence in erythrocytes that was diminished. These data indicate that hyperthyroidism is associated with a pro-oxidant condition characterized by an enhancement in circulating and urinary lipid peroxidative indexes, which is suppressed by PTU treatment. It is suggested that this condition might reflect an oxidative stress at cellular level in tissues which are target for thyroid hormone action with a calorigenic response.

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