The
kisspeptin (
metastin) is an endogenous
peptide, which regulates human reproduction by modulating
gonadotropin-releasing hormone (
GnRH) secretion.
Kisspeptin was detected in peripheral blood, although
GnRH was not. Previously, we measured plasma
kisspeptin levels in male healthy subjects and patients with
hypogonadism using
enzyme immunoassay (EIA) to elucidate a normal range in healthy males and clinical implications of
kisspeptin in male
hypogonadism. We suggested that the plasma
kisspeptin levels were received feedback from
testosterone. In this study, we focused female subjects and elucidated the relationship between menstrual cycle and plasma
kisspeptin levels to understand
kisspeptin-hypothalamic-pituitary-gonadal axis. We measured plasma
kisspeptin levels in eight female volunteers. The plasma
kisspeptin levels in female are significantly higher than those in male. There are no significant correlation between plasma
kisspeptin levels and sexual
hormones. We revealed that the
kisspeptin might stimulate a start of menstruation as a trigger, and progress menstruation covered for weakened ovarian function. We suggest that
kisspeptin may be closely related with menstrual cycle and that the measurement of plasma
kisspeptin levels is useful for understanding of reproductive system.