Dose-dependent effect of melatonin on life span and spontaneous tumor incidence in female SHR mice.
From the age of 3 months until their natural death, female Swiss-derived SHR mice were given melatonin with their drinking water (2 or 20mg/l) for 5 consecutive days every month. Intact mice served as controls. There were 54 mice in each group. The results of this study show that the treatment of melatonin did not significantly influence food consumption, but its administration at lower doses did decrease the body weight of mice; it slowed down the age-related switching-off of estrous function; it did not influence the frequency of chromosome aberrations in bone marrow cells; it did not influence mean life span; and it increased life span of the last 10% of the survivors in comparison to controls. We also found that treatment with low dose melatonin (2mg/l) significantly decreased spontaneous tumor incidence (by 1,9-fold), mainly mammary carcinomas, in mice whereas higher doses (20mg/l) failed to influence tumor incidence as compared to controls. For this reason, we conclude that the effect of melatonin as a geroprotector is dose-dependent.
Anisimov
Vladimir N
VN
N.N. Petrov Research Institute of Oncology, Pesochny-2, St.Petersburg 197758, Russian Federation. aging@mail.ru
Alimova
Irina N
IN
Baturin
Dmitri A
DA
Popovich
Irina G
IG
Zabezhinski
Mark A
MA
Rosenfeld
Svetlana V
SV
Manton
Kenneth G
KG
Semenchenko
Anna V
AV
Yashin
Anatoli I
AI
D000818:Animals; D001835:Body Weight / Q000187:drug effects; D002869:Chromosome Aberrations; D004305:Dose-Response Relationship, Drug; D004435:Eating / Q000187:drug effects; D004971:Estrus / Q000187:drug effects; D005260:Female; D015994:Incidence; D008136:Longevity / Q000187:drug effects*; D008550:Melatonin / Q000494:pharmacology*; D051379:Mice; D008815:Mice, Inbred Strains; D009369:Neoplasms / Q000517:prevention & control*; D011897:Random Allocation
D008550:Melatonin