EFFECT OF METFORMIN ON GLUCOSE DISPOSAL AND HYPERINSULINEMIA IN A 14-YEAR-OLD BOY WITH ACANTHOSIS NIGRICANS

We report the treatment of a 14-year-old Indian boy with acanthosis ni gricans and hyperinsulinaemia with metformin in an attempt to improve his skin lesions, Oral metformin was used for 6 months with assessment of insulin status during an intravenous glucose tolerance test and hy perinsulinaemic-euglycaemic clamping before and after treatment, The f irst-phase insulin response reduced from 19,593 to 5,410 pmol/l/min (n ormal 1,900-13,400), and the second-phase insulin response improved fr om 59,120 to 34,020 pmol/l/min (normal 2,900-18,100). During hyperinsu linaemic-euglycaemic clamping hepatic glucose production was normally suppressed prior to therapy, but peripheral glucose remained abnormall y low, 152 and 138% of basal (expected 199%). The acanthosis nigricans remained unaltered but over this period puberty progressed and his bo dy mass index increased, We conclude that, in this patient, metformin had a minimal effect on the hyperinsulinism and none on the acanthosis nigricans in the relatively short term, but further studies in more p atients over longer time intervals are warranted.