The formulation development of melatonin (MLT) for infants and children with neurodevelopmental difficulties was fully investigated.
This high evolutionary age has led to the development of diverse functions of melatonin in different organisms, such as the detoxification of reactive oxygen species and anti-stress effects.
Further in-depth studies in diurnal species are required to evaluate all the aspects of the potential effects of melatonin on embryonic development and cautious approach to using melatonin or melatonin receptor agonists during pregnancy is advised.
The role of the pineal gland, the major source of melatonin, in the development of breast [ 3] and mammary [ 4, 5] cancer has been clearly documented.
The role of melatonin in tumour development has been under intensive study during the last few decades.
Therefore, several melatonin agonists have been developed in recent years and examined in clinical trials for the treatment of insomnia (for a current review of melatonin receptor agonist development, see Turek and colleagues 3).
Experiments in animals have confirmed beneficial effects of melatonin administration on oocyte maturation and embryo development [ 31].
In zebrafish, the pineal axonal projections are among the first to develop, with melatonin production and expression of melatonin receptors being initiated around 18 hpf, and soon after modulating the rate of zebrafish embryonic development and cell division [10].
An agonist of melatonin is in the advanced development stage and could be available in short time.
In conclusion, undernutrition impaired the viability of sheep embryos in the RS, particularly among ewes that were given melatonin supplements subcutaneously, but melatonin appeared to improve embryo quality in the AS, which suggests that the mechanisms involved in the interactive effects of melatonin and nutrition on embryo development are influenced by season.
