HETEROGENEITY IN BETA-CELL ACTIVITY, HEPATIC INSULIN-CLEARANCE AND PERIPHERAL INSULIN SENSITIVITY IN WOMEN WITH POLYCYSTIC OVARY SYNDROME

The aim of this study was to evaluate the impact of reduced peripheral insulin sensitivity, beta cell hypersecretion and reduced hepatic ins ulin clearance in the hyper-insulinaemia of lean and obese PCOS patien ts, A total of 35 women with polycystic ovary syndrome (PCOS) and 10 l ean normo-ovulatory controls underwent an oral glucose tolerance test and an euglycaemic-hyper-insulinaemic clamp study, PCOS patients were classified into four groups according to their BMI and insulin secreti on (normo-lean; normo-obese; hyper-lean; hyper-obese), and results wer e compared between groups and with the controls, All the PCOS groups s howed significantly higher insulin secretion than controls; there were no differences in insulin response to glucose load between lean and o bese normo-and hyper-insulinaemic patients, Secretion of c-peptide was greater in PCOS groups than controls, All the hyper-insulinaemic PCOS patients had lower values of hepatic insulin clearance, independent o f BMI, when compared either with controls (P < 0.001) or with PCOS nor mo-insulinaemic women (P < 0.01), Normo- and hyper-insulinaemic obese patients had similar total body glucose utilization (M value), which w as lower than in lean PCOS subjects and controls, Our results suggest that evaluation of insulin resistance alone does not fully characteriz e the PCOS population; differences in liver metabolism of insulin are present in obese insulin resistant subjects and in lean patients with normal insulin sensitivity when divided into normo- and hyper-insulina emic subgroups, Insulin resistance and hyper-insulinaemia may represen t two distinct features of the insulin disorder in PCOS: the former ap pear to reflect the presence of obesity, while the latter may be a pri mary feature of PCOS.