The role of LH in ovarian stimulation - Exogenous LH: let's design the future

Historically, follicular stimulation protocols have included both FSH and L H in an attempt to mimic the physiology of normal human folliculogenesis. H owever, many recent gonadotrophin administration regimens have completely e liminated LH bioactivity, The importance and the amount of LH necessary for optimal follicular stimulation has been a topic of debate. Several recent studies have added to our understanding of the actions of androgens, oestro gens, gonadotrophins, and insulin on the follicle-oocyte unit, allowing a l ess speculative approach, Moreover, the availability of human gonadotrophin s synthesized by recombinant DNA technology and gonadotrophin-releasing hor mone (GnRH) antagonists, should soon permit a precise in-vivo assessment an d re-evaluation of the historical 2-cell, two-gonadotrophin hypothesis. The se pharmacological tools mag also provide essential insights into the physi ological roles of FSH and LH in human follicular development and oocyte mat uration. The recombinant gonadotrophins give clinicians the unique opportun ity to tailor ovarian stimulation regimens according to the patient's medic al history, in an effort both to maximize oocyte yield and to improve oocyt e quality.