I. Nir et al., THE ANTIGONADOTROPHIC EFFECT OF MELATONIN IN SYRIAN-HAMSTERS IS MODULATED BY PROSTAGLANDIN, Journal of neural transmission, 95(3), 1994, pp. 173-177
PGE2 was shown to play an essential role in the gonado-inhibiting effe
ct of melatonin in Syrian hamsters by transforming the neuroendocrine
signal to gonadal reactivity. Prostaglandin is a vital link in the tra
nsduction of photoperiodic information into gonadal function and the d
ifference in its levels brought about by melatonin given at different
times of the day could explain the phenomenon why gonadal involution o
ccurs only upon administration of melatonin towards the end of the day
. It appears also that the melatonin signal is decoded in the pituitar
y, probably involving the short loop negative feedback of LH on LH-RH
hormones.