Injections of alpha-melanocyte stimulating hormone affect pineal serotonin, melatonin and N-acetyltransferase activity.
To determine if exogenously administered alpha-melanocyte stimulating hormone (alpha-MSH) affects nighttime pineal N-acetyltransferase activity, pineal levels of 5-hydroxytryptophan, serotonin and melatonin, and plasma prolactin levels, adult male hamsters were injected at 1900 hr (lights out 2000-0600 hr) with two doses of the peptide and killed at 0300 hr. The low dose of alpha-MSH (200 ng) produced a significant fall in pineal serotonin, pineal NAT activity and plasma prolactin values. The high dose of the peptide (20 micrograms) increased circulating prolactin titers and pineal serotonin levels and caused a concomitant decrease in pineal melatonin levels.
D006916:5-Hydroxytryptophan / Q000378:metabolism; D000123:Acetyltransferases / Q000378:metabolism*; D000818:Animals; D006224:Cricetinae; D007267:Injections; D008297:Male; D009074:Melanocyte-Stimulating Hormones / Q000008:administration & dosage / Q000494:pharmacology*; D008550:Melatonin / Q000378:metabolism*; D008647:Mesocricetus; D010870:Pineal Gland / Q000187:drug effects / Q000201:enzymology / Q000378:metabolism*; D011388:Prolactin / Q000097:blood; D012701:Serotonin / Q000378:metabolism*
D012701:Serotonin; D011388:Prolactin; D009074:Melanocyte-Stimulating Hormones; D006916:5-Hydroxytryptophan; D000123:Acetyltransferases; D008550:Melatonin