Ml. Hull et al., PREOVULATORY OXYTOCIN ADMINISTRATION PROMOTES THE ONSET OF THE LUTEINIZING-HORMONE SURGE IN HUMAN FEMALES, Human reproduction, 10(9), 1995, pp. 2266-2269
Luteinizing hormone (LH) secretion during the ovulatory cycle is belie
ved to be predominantly regulated by gonadotrophin-releasing hormone,
Investigations in animals have strongly suggested that oxytocin also p
articipates in LH control and the physiological events controlling LH
surge initiation. In the human female, however, there has been no evid
ence supporting oxytocin's involvement in the processes leading to ovu
lation. In this study the effect of a preovulatory infusion of oxytoci
n on the onset of the LH surge was investigated in women aged 20-35 ye
ars who had natural ovulatory menstrual cycles of lengths between 25-3
5 days, Vaginal ultrasound scanning monitored follicular growth during
the late follicular phase. When a follicle >14 mm in diameter was obs
erved each woman was randomized into one of two groups. One group (n =
8) received an oxytocin infusion of 256 mIU/min for 2 h, the other gr
oup (n = 8) received normal saline, The women who were administered ox
ytocin at this late follicular stage had an earlier onset of the LH su
rge than those who had received saline (P < 0.01). The results indicat
e that oxytocin promotes the onset of the LH surge in humans.