Apr 1, 1994

Effects of chronic melatonin administration on adrenal medulla catecholamine metabolism in adult male golden hamsters

Journal of Pineal Research
A I EsquifinoR W Steger


The role of melatonin on adrenal medullary function was evaluated in adult golden (Syrian) hamsters injected daily at either 0800 or 1600 with melatonin (25 micrograms/hamster) or vehicle (0.1% ethanol in saline). Sixty days after initiation of treatment and 16 or 24 hr after the last injection of melatonin, animals were killed by decapitation and blood and tissue collected. Plasma prolactin levels were reduced by chronic administration of melatonin only when animals were treated at 1600. Tyrosine hydroxylase (TH) activity in the adrenal medulla was not changed by either morning or afternoon administration of melatonin. Phenylethanolamine-N-methyl transferase (PNMT) was changed by afternoon administration of melatonin. Morning and afternoon melatonin injections led to the reduction of both adrenal monoamine oxidase (MAO) and catechol-O-methyl transferase (COMT) activities although the afternoon injections led to a greater magnitude of change. Norepinephrine and epinephrine contents were significantly reduced by morning melatonin administration but were not changed by afternoon administration of the hormone. These data suggest that melatonin has direct and possibly indirect effects on adrenal medullary function in the hamster. H...Continue Reading

Mentioned in this Paper

Mesocricetus auratus
COMT gene
Ethanol Measurement
Catecholamine Metabolic Process
Monoamine Oxidase [PK]
Transcription Initiation

About this Paper

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