
%0 Journal Article
%A Kennaway, DJ 
%A Royles, P 
%A A Dunstan, E 
%A Hugel, HM 
%T Prolactin Response in Border-Leicester X Merino Ewes to Administration of Melatonin, Melatonin Analogues, a Melatonin Metabolite and 6-Methoxybenzoxazolinone
%J Australian Journal of Biological Sciences
%D 1986/12/01
%V 39
%N 4
%P 427-433
%K 
%R https://doi.org/10.1071/BI9860427
%U https://www.publish.csiro.au/paper/BI9860427 
%X The effect of structural modifications of the melatonin molecule on plasma half-life of the analogues and basal prolactin secretion was studied in Border-Leicester x Merino ewes. Halogenation at position 6 and/or unsaturation of the 2,3-double bond of the melatonin molecule slightly lengthened the halflife of the analogues. Melatonin, 6-chloromelatonin, 2,3-dihydromelatonin and 6-chloro-2,3-dihydromelatonin decreased plasma prolactin to 31, 45, 54 and 48% of control levels respectively when administered daily (100 p.g at 1600 h) for 21 days. The brain metabolite of melatonin, N-acetyl-N'-formyl- 5-methoxykynurenamine, and the putative natural melatonin analogue, 6-methoxybenzoxazolinone, failed to affect prolactin levels when administered in a similar manner. These results indicate that certain structural modifications to the melatonin molecule can be tolerated biologically; however, the modifications reported here still did not prevent rapid clearance from the circulation. 
