RESUMO
The causes and consequences of the insulin resistance that accompanies the polycystic ovary Syndrome (PCOS) are still controversial. The hyperandrogenism does not appear any more as a causal factor but on the contrary is likely to be a consequence, via the ovarian effects of hyperinsulinism. These are still not clearly understood in their molecular aspects, but their reality is undoubtful in view of some clinical studies which showed an improvement following by the reduction of hyperinsulinism. Therefore, the aetiopathogenic role of the insulin resistance in PCOS becomes more and more obvious but it cannot be split from the likely implication of the intra-ovarian growth factors, and more especially the IGF 1 which could act synergistically with it. Moreover, the presence of LH seems to be still a pre-requisite to the ovarian action of insulin. The therapeutical incidences of these hypothesis are obvious and should improve in the next future the medical management of PCOS.