Pinealectomy or Melatonin Implantation Does Not Affect Prolactin Surge or Luteal Function in Pseudopregnant Rats.

Tamura, Hiroshi; Nakamura, Yasuhiko; Takiguchi, Shuji; Kashida, Shiro; Yamagata, Yuriko; Sugino, Norihiro; Katô, Hiroshi

doi:10.1507/endocrj.45.377

Cited by 13 publications

(8 citation statements)

References 39 publications

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“…Intrafollicular concentrations of melatonin were measured by radioimmunoassay as reported previously [32]. Briefly, serum melatonin (500 mL) was extracted with 2 mL of chloroform.…”

Section: Methodsmentioning

confidence: 99%

Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

Tamura

Takasaki

Miwa

et al. 2007

Journal of Pineal Research

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We investigated the relationship between oxidative stress and poor oocyte quality and whether the antioxidant melatonin improves oocyte quality. Follicular fluid was sampled at oocyte retrieval during in vitro fertilization and embryo transfer (IVF-ET). Intrafollicular concentrations of 8-hydroxy-2'-deoxyguanosine (8-OHdG) in women with high rates of degenerate oocytes were significantly higher than those with low rates of degenerate oocytes. As there was a negative correlation between intrafollicular concentrations of 8-OHdG and melatonin, 18 patients undergoing IVF-ET were given melatonin (3 mg/day), vitamin E (600 mg/day) or both melatonin and vitamin E. Intrafollicular concentrations of 8-OHdG and hexanoyl-lysine adduct were significantly reduced by these antioxidant treatments. One hundred and fifteen patients who failed to become pregnant with a low fertilization rate (< or =50%) in the previous IVF-ET cycle were divided into two groups during the next IVF-ET procedure; 56 patients with melatonin treatment (3 mg/day) and 59 patients without melatonin treatment. The fertilization rate was improved by melatonin treatment compared to the previous IVF-ET cycle. However, the fertilization rate was not significantly changed without melatonin treatment. Oocytes recovered from preovulatory follicles in mice were incubated with H2O2 for 12 hr. The percentage of mature oocytes with a first polar body was significantly reduced by addition of H2O2 (300 microm). The inhibitory effect of H2O2 was significantly blocked by simultaneous addition of melatonin. In conclusion, oxidative stress causes toxic effects on oocyte maturation and melatonin protects oocytes from oxidative stress. Melatonin is likely to improve oocyte quality and fertilization rates.

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“…Intrafollicular concentrations of melatonin were measured by radioimmunoassay as reported previously [32]. Briefly, serum melatonin (500 mL) was extracted with 2 mL of chloroform.…”

Section: Methodsmentioning

confidence: 99%

Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

Tamura

Takasaki

Miwa

et al. 2007

Journal of Pineal Research

Self Cite

580

483

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show abstract

“…Serum melatonin concentrations were measured by radioimmunoassay, as reported previously [19]. Briefly, 500 μ L of serum was extracted with 2 mL of chloroform.…”

Section: Methodsmentioning

confidence: 99%

Melatonin treatment in peri‐ and postmenopausal women elevates serum high‐density lipoprotein cholesterol levels without influencing total cholesterol levels

Tamura

Nakamura

Narimatsu

et al. 2008

Journal of Pineal Research

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The purpose of this study was to investigate the effects of melatonin on lipid metabolism in peri- and postmenopausal women. Forty-six women were enrolled in these studies. The relationship between night-time serum melatonin levels and serum total cholesterol, triglycerides, high-density lipoprotein (HDL) cholesterol, low-density lipoprotein (LDL) cholesterol was investigated in 36 women. Night-time serum melatonin levels had a negative correlation with serum total cholesterol and LDL-cholesterol, and a loose positive correlation with HDL-cholesterol. To examine the effects of exogenous melatonin on lipid metabolism, serum levels of total cholesterol, HDL-cholesterol, LDL-cholesterol and triglycerides were determined in 10 women before the onset of therapy and after 1 month of oral melatonin administration (1 mg melatonin daily). Melatonin administration significantly increased the serum levels of HDL-cholesterol. These results show that melatonin may influence cholesterol metabolism and suggest that the melatonin administration may become a new medical application for improvement of lipid metabolism and prevention of cardiovascular disease in peri- and postmenopausal women.

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“…Melatonin plays a key role in a variety of important physiological functions, including circadian rhythms [7], reproductive [8], neuroendocrine [9], cardiovascular [10], neuroimmunological [11], oncostatic actions [12]. We already reported that melatonin plays a role in lipid metabolism [13], pregnancy and parturition time [14-16], and corpus luteum (CL) function [17]. Some effects of melatonin are mediated through specific membrane receptors, but many of them seem to rely on its potential as a direct free radical scavenger, a process that requires no receptor.…”

Section: Intoductionmentioning

confidence: 99%

The role of melatonin as an antioxidant in the follicle

et al. 2012

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Melatonin (N-acetyl-5-methoxytryptamine) is secreted during the dark hours at night by pineal gland, and it regulates a variety of important central and peripheral actions related to circadian rhythms and reproduction. It has been believed that melatonin regulates ovarian function by the regulation of gonadotropin release in the hypothalamus-pituitary gland axis via its specific receptors. In addition to the receptor mediated action, the discovery of melatonin as a direct free radical scavenger has greatly broadened the understanding of melatonin's mechanisms which benefit reproductive physiology. Higher concentrations of melatonin have been found in human preovulatory follicular fluid compared to serum, and there is growing evidence of the direct effects of melatonin on ovarian function especially oocyte maturation and embryo development. Many scientists have focused on the direct role of melatonin on oocyte maturation and embryo development as an anti-oxidant to reduce oxidative stress induced by reactive oxygen species, which are produced during ovulation process. The beneficial effects of melatonin administration on oocyte maturation and embryo development have been confirmed by in vitro and in vivo experiments in animals. This review also discusses the first application of melatonin to the clinical treatment of infertile women and confirms that melatonin administration reduces intrafollicular oxidative damage and increase fertilization rates. This review summarizes our recent works and new findings related to the reported beneficial effects of melatonin on reproductive physiology in its role as a reducer of oxidative stress, especially on oocyte maturation and embryo development.

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Pinealectomy or Melatonin Implantation Does Not Affect Prolactin Surge or Luteal Function in Pseudopregnant Rats.

Cited by 13 publications

References 39 publications

Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

Oxidative stress impairs oocyte quality and melatonin protects oocytes from free radical damage and improves fertilization rate

Melatonin treatment in peri‐ and postmenopausal women elevates serum high‐density lipoprotein cholesterol levels without influencing total cholesterol levels

The role of melatonin as an antioxidant in the follicle

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