introduction: melatonin acts as an indirect antioxidant and is a powerful direct free radical scavenger and direct responses to melatonin in the gonads are detected. this study aims to investigate the influence of different doses of melatonin on preantral follicle development and oogenesis of in vitro cultured mouse ovarian follicles. materials and methods: preantral follicles with diameters of...

Melatonin is a somewhat mysterious substance. In animals, melatonin is secreted from the pineal gland during the night. It acts as a hormone, functioning as a circadian mediator for time information over the course of each day, and is also able to eliminate free radicals (reactive oxygen species). Melatonin also exists in higher plants (edible plants), and is inadvertently obtained from daily m...

Melatonin has been speculated to be mainly synthesized by mitochondria. This speculation is supported by the recent discovery that aralkylamine N-acetyltransferase/serotonin N-acetyltransferase (AANAT/SNAT) is localized in mitochondria of oocytes and the isolated mitochondria generate melatonin. We have also speculated that melatonin is a mitochondria-targeted antioxidant. It accumulates in mit...

OBJECTIVE In this experimental study, we aimed to investigate the role of melatonin on uterine myoelectrical activity of non-pregnant rats. MATERIAL AND METHODS Forty-six female rats were assigned to six groups: (1) control; (0.2 mL 0.9% NaCl was injected intravenously (IV), n=6); (2) melatonin applied as 0.4 mg/kg/IV (n=8); (3) melatonin applied as 4 mg/kg/IV (n=8); (4) single dose of oxytoc...

In addition to marked seasonal changes in reproductive, metabolic, and other physiological functions, many vertebrate species undergo seasonal changes in immune function. Despite growing evidence that photoperiod mediates seasonal changes in immune function, little is known regarding the neuroendocrine mechanisms underlying these changes. Increased immunity in short days is hypothesized to be d...

Melatonin (N-acetyl-5-methoxytryptamine) plays critical roles in plant growth and development and during the response to multiple abiotic stresses. However, the roles of melatonin in plant response to K+ deficiency remain largely unknown. In the present study, we observed that the endogenous melatonin contents in bermudagrass were remarkably increased by low K+ (LK) treatment, suggesting that m...

Objective(s): Traumatic brain injury (TBI) is one of the most common causes of death and disability in modern societies. The role of steroids and melatonin is recognized as a neuroprotective factor in traumatic injuries. This study examined the role of melatonin receptors in the neuroprotective effects of estrogen. Materials and Methods: Seventy female ovariectomized Wistar rats were divided in...

objective: ionizing radiation interacts with biological systems to induce excessive fluxes of free radicals that attack various cellular components. melatonin has been shown to be a direct free radical scavenger and indirect antioxidant via its stimulatory actions on the antioxidant system.the aim of this study was to evaluate the antioxidant role of melatonin against radiation-induced oxidativ...

Although nearly ubiquitous in nature, the precise biological significance of endogenous melatonin is poorly understood in phylogenetically basal taxa. In the present work, we describe insights into the functional role of melatonin at the most "basal" level of metazoan evolution. Hitherto unknown morphological determinants of melatonin distribution were evaluated in Nematostella vectensis by det...

In this experiment we investigated whether the lack of the nocturnal melatonin peak under constant light would cause an increase in testosterone sensitivity. Castrated rats were kept under periodic or constant light for one week. They received a daily injection of vehicle, testosterone propionate (125 micrograms), melatonin (50 micrograms) or testosterone plus melatonin (125 micrograms + 50 mic...