New insights into the role of LH in early ovarian follicular growth: a possible tool to optimize follicular recruitment

Evidence shows that LH participates in enhancing transition from the early stage to the antral stage of folliculogenesis. It has been demonstrated that functional LH receptors are expressed, albeit at a very low level and even in smaller follicles, during the phase that was traditionally considered to be gonadotrophin independent, suggesting a role for LH in accelerating the rate of progression of non-growing and primary follicles to the preantral/antral stage. Hypogonadotropic hypogonadism, together with other clinical conditions of pituitary suppression, has been associated with reduced functional ovarian reserve. The reduction in LH serum concentration is associated with a low concentration of anti-Mueurollerian hormone. This is the case in hypothalamic amenorrhoea, pregnancy, long-term GnRH-analogue therapy and hormonal contraception. The effect seems to be reversible, such that after pregnancy and after discontinuation of drugs, the functional ovarian reserve returns to the baseline level. Evidence suggests that women with similar primordial follicle reserves could present with different numbers of antral follicles, and that gonadotrophins may play a fundamental role in permitting a normal rate of progression of follicles through non-cyclic folliculogenesis. The precise role of gonadotrophins in early folliculogenesis, as well as their use to modify the functional ovarian reserve, must be investigated.

Automated summary

Evidence suggests that LH plays a role in enhancing the transition from early follicle to antral follicle stage. Low levels of LH receptors have been found in smaller follicles, even during the traditionally considered gonadotropin-independent phase, indicating a potential role for LH in accelerating the progression of non-growing and primary follicles. Reduced functional ovarian reserve has been associated with conditions such as hypogonadotropic hypogonadism and pituitary suppression, which are characterized by decreased LH serum concentration. This effect seems to be reversible, as the functional ovarian reserve returns to baseline levels after pregnancy or discontinuation of certain medications. Gonadotropins may also influence the number of antral follicles, independently of the primordial follicle reserve. Further research is needed to fully understand the precise role of gonadotropins in early folliculogenesis and their potential use in modifying the functional ovarian reserve.