Pf. Ashley et al., Effect of oral melatonin administration on sex hormone, prolactin, and thyroid hormone concentrations in adult dogs, J AM VET ME, 215(8), 1999, pp. 1111-1115
Citations number
26
Categorie Soggetti
Veterinary Medicine/Animal Health
Journal title
JOURNAL OF THE AMERICAN VETERINARY MEDICAL ASSOCIATION
Objective-To determine the effect of oral melatonin (MT) administration on
serum concentrations of sex hormones, prolactin, and thyroxine in dogs.
Design-Prospective study.
Animals-8 male and 8 female adult sexually intact dogs.
Procedure-5 male and 5 female dogs were treated with MT (1.0 to 1.3 mg/kg [
0.45 to 0.59 mg/lb] of body weight), PO, every 12 hours for 28 days; the ot
her 6 dogs were used as controls. Blood samples were collected on days 0, 1
4, and 28, and serum concentrations of estradioi-17 beta, progesterone, tes
tosterone, androstenedione, 17-hydroxyprogesterone (17-HP), dihydroepiandro
stenedione sulfate (DHEAS), prolactin, and thyroxine were determined. On da
y 5, serum MT concentrations were measured before and periodically for up t
o 8 hours after MT administration in 4 treated dogs.
Results-Female dogs treated with MT had significant decreases in serum estr
adiol, testosterone, and DHEAS concentrations between days 0 and 28. Male d
ogs treated with MT had significant decreases in serum estradiol and 17-HP
concentrations between days 0 and 28. Serum MT concentrations increased sig
nificantly after MT administration and remained high for at least 8 hours.
Prolactin and thyroxine concentrations were unaffected by treatment.
Conclusions and Clinical Relevance-Melatonin is well absorbed following ora
l administration and may alter serum sex hormone concentrations.