It is becoming increasingly common for veterinarians to see clients who inquire about using supplements for their pets' health. Many times, the client has done her own research and has already started the pet on a particular supplement. She would like the veterinarian's approval and encouragement. Since most of us learned little to nothing about natural medicine in veterinary school and likely do not have the time to become proficient in this area (unless that is an area of interest and specialization), articles such as this one help fill in the gaps for the doctor to not only converse with the client intelligently but also make sound and safe recommendations.
It is important for doctors to have a basic knowledge of natural supplements (or at least have a colleague to whom they can refer for help in this area). With these thoughts in mind, I want to share some basic information about melatonin, a supplement clients often inquire about (likely because many of them are taking it, as well).
Note: I've included several resources for suggested reading on the topic and encourage readers with a deeper interest to pursue additional study to become more familiar with the supplement. Note most references for naturopathic medicine are from human medical journals as there is little independent study in the veterinary field.
The basics
Melatonin (N-acetyl-5-methoxytryptamine,) is a hormone produced by the pineal gland through conversion of tryptophan into serotonin, which is then converted into melatonin (via hydroxylation and decarboxylation.) In people and animals, melatonin has also been reported to be produced in the retina, bone marrow cells, platelets, skin, lymphocytes, Harderian gland, cerebellum, and especially in the gastrointestinal tract (enterochromaffin cells.) The release of gastrointestinal melatonin into the circulation seems to follow the cycle of food intake, particularly tryptophan intake. The concentration of melatonin in the gastrointestinal tract surpasses blood levels by 10 to 100 times. There is at least 400 times more melatonin in the gastrointestinal tract than in the pineal gland.
