Effects of melatonin ingestion on cAMP and cGMP levels in human plasma

I. Zhdanova
1999 Journal of Endocrinology  
The effects of daytime melatonin treatment (0·3 mg) on cAMP and cGMP levels in platelet-rich plasma (PRP) and platelet-poor plasma (PPP) were investigated in 14 normal human subjects (age ... 26·2 3·2 years). Plasma levels of cAMP, cGMP and melatonin were measured before and at intervals for 3 h after the treatment was administered at 1300 h. Plasma melatonin concentrations reached peak levels 1 h after the treatment (mean .. 182·3 43·5 pg/ml). The mean areas under the curve (AUC) for the
more » ... ime-cGMP concentration curves in PPP and in PRP were significantly increased after melatonin treatment compared with those observed after placebo treatment (P=0·001). No significant difference in cGMP levels was observed between PPP and PRP. Increase in self-reported sleepiness after melatonin treatment positively correlated with increase in plasma cGMP levels (r=0·92). The mean AUC for the time-cAMP concentration in PRP, but not in PPP, was increased 1 h after melatonin treatment compared with that observed after placebo treatment, but not thereafter. No correlation between individual PRP or PPP cAMP levels and subjective sleepiness was observed. These results demonstrate a stimulating effect of melatonin treatment on plasma cGMP levels in humans and suggest a correlation between the increase in circulating cGMP levels and the sleep-promoting effect of the pineal hormone.
doi:10.1677/joe.0.1630457 pmid:10588819 fatcat:t2srjt5y5zc2ra5ceayy7cclxy