Hypersecretion of luteinizing hormone (LH) is a significant cause of i
nfertility and miscarriage in women with the polycystic ovary syndrome
. Many theories have been suggested for the aetiology of pituitary ove
rsecretion of LH. These include increased pulsatility of gonadotrophin
releasing hormone (GnRH) hypothalamic dysfunction, altered pituitary
sensitivity to GnRH, hyperinsulinaemic stimulation of the pituitary gl
and and perturbed ovarian-pituitary feedback of steroid hormones. None
of these hypotheses fully explain the phenomenon of LH hypersecretion
and there has been much debate in the literature on this subject. Thi
s paper reviews some of the important clinical studies that have exami
ned the evolving story of hypersecretion of LH and presents in-vivo an
d in-vitro evidence that suggests that disordered ovarian-pituitary fe
edback is central to the problem, possibly through a perturbed secreti
on of nonsteroidal ovarian hormones.