Abstract: Objective To investigate the correlation of the total testosterone (TT) level with insulin secretion and resistance in patients with acanthosis nigricans (AN) and non-acanthosis nigricans (NAN). Methods This study was conducted in a total of 639 overweight patients (body mass index ≥24 kg/m2), including 137 female AN patients, 277 female NAN patients, 129 male AN patients, and 146 male NAN patients. Each group was further divided into 4 subgroups according to the quartile of TT level for comparison of insulin secretion and insulin resistance parameters. Results Both female and male patients with AN showed obvious hyperinsulinemia with increased area under the curve for insulin (AUC-INS) (P<0.05), increased homeostatic model assessment of insulin resistance (HOMA-IR) index (P<0.05) and decreased whole-body insulin sensitivity index (WBISI) (P<0.01) as compared with those in NAN groups, but these parameters did not show significant variations with the change of TT levels. In female patients with NAN, insulin secretion level increased progressively as the TT level increased; the AUC-INS increased (P<0.01) and WBISI decreased significantly (P<0.05) when the TT levels increased to Q4. In male patients with NAN, insulin secretion level increased progressively as the TT levels decreased, and the AUC-INS increased (P<0.05) and the WBISI decreased significantly (P<0.05) when the TT levels decreased to Q1. Conclusions The TT level has a significant effect on insulin resistance and insulin secretion, but its effect varies between genders and is more significant in NAN patients than in AN patients.

Key words: obesity; acanthosis nigricans; total testosterone; insulin secretion; insulin resistance