Melatonin in Human Preovulatory Follicular Fluid*

Abstract

Melatonin, the major hormone of the pineal gland, has antigonadotrophic activity in many mammals and may also be involved in human reproduction. Melatonin suppresses steroidogenesis by ovarian granulosa and luteal cells in vitro. To determine if melatonin is present in the human ovary, preovulatory follicular fluids (n = 32) from 15 women were assayed for melatonin by RIA after solvent extraction. The fluids were obtained by laparoscopy or sonographically controlled follicular puncture from infertile women undergoing in vitro fertilization and embryo transfer. All patients had received clomiphene citrate, human menopausal gonadotropin, and hCH to stimulate follicle formation. Blood samples were obtained by venipuncture 30 min or less after follicular aspiration. All of the follicular fluids contained melatonin, in concentrations [36.5 +/- 4.8 (+/- SEM) pg/mL] substantially higher than those in the corresponding serum (10.0 +/- 1.4 pg/mL). A positive correlation was found between follicular fluid and serum melatonin levels in each woman (r = 0.770; P less than 0.001). These observations indicate that preovulatory follicles contain substantial amounts of melatonin that may affect ovarian steroidogenesis.

Melatonin regulates delayed embryonic development in the short-nosed fruit bat, Cynopterus sphinx

“…This is consistent with the earlier reports on human and rat demonstrating the presence of MTNR1A and MTNR1B in granulosa cells and luteal cells (Soares et al 2003). The presence of high levels of melatonin in follicular fluid in human and binding sites in the ovary (Brzezinski et al 1987, Ronnberg et al 1990, Niles et al 1999 and, now, the presence of MTNR1A and MTNR1B in ovary suggest that melatonin directly acts as a modulator of ovarian functions.…”

The effects of melatonin on in vitro oocyte competence and embryo development in sheep

“…Reported increases in prolificacy subsequent to the administration of melatonin in sheep might be due to the direct effect of exogenous melatonin on the ovine oocyte, which has been observed in other species (Ishizuka et al, 2000;Na et al, 2005;Parka et al, 2006). Several studies have reported the presence of melatonin in human pre-ovulatory follicular fluid and the seasonal variation of its contents (Brzezinski et al, 1987;Yie et al, 1995), and melatonin receptors have been found on rat, mouse, and porcine ovarian cells (Soares et al, 2003;Na et al, 2005;Kang et al, 2008), which suggests that melatonin has a direct effect on oocyte competence.…”

The influences of weather on patients with different ovarian responses in the treatment of assisted reproductive technology

“…The involvement of melatonin in the steroid genesis of human ovaries has been documented (19,20). Webley and Luck (19) also reported direct stimulation of melatonin on hCG.…”

“…Webley and Luck (19) also reported direct stimulation of melatonin on hCG. Melatonin was thought to enhance hCG stimulation of progesterone production by human granulosa cells in culture (20). Yie et al (21,22) reported higher concentrations of melatonin and progesterone during the dark season of the year and of oestradiol during the light season from pre-ovulatory follicular fluids.…”