title: Exercise intensity dependent inhibition of 1-methyl-1-nitrosourea induced mammary carcinogenesis in female F-344 rats.
abstract: The objective of this experiment was to evaluate the effects of treadmill exercise on tumor induction in an experimental model for breast cancer. Female F-344 rats were injected i.p. with 50 mg MNU/kg body wt at 50 and 57 days of age. Animals were assigned to one of five groups: sham exercise or 35% or 70% maximal treadmill running intensity for 20 or 40 min/day, 5 days per week. These work rates represent an exercise intensity level generally considered insufficient to improve cardiovascular fitness (35% maximal intensity) or an aerobic level of exercise sufficient to improve cardiovascular fitness in humans (70% maximal intensity). Rats were exercised for 3 months following carcinogen administration at which time the experiment was terminated. Mammary cancer incidence was reduced by as much as 37% and cancer multiplicity by < 60% at the highest exercise intensity. Unexpectedly, the degree of protection against cancer was proportional to the intensity but not to the duration of exercise.
authors.affiliation: Division of Laboratory Research, AMC Cancer Research Center, Denver, CO 80214, USA.
authors.forename: H J
authors.initials: HJ
authors.lastname: Thompson
authors.forename: K C
authors.initials: KC
authors.lastname: Westerlind
authors.forename: J
authors.initials: J
authors.lastname: Snedden
authors.forename: S
authors.initials: S
authors.lastname: Briggs
authors.forename: M
authors.initials: M
authors.lastname: Singh
mesh_terms: D000818:Animals; D004734:Energy Metabolism; D005260:Female; D008325:Mammary Neoplasms, Experimental / Q000139:chemically induced / Q000517:prevention & control*; D008770:Methylnitrosourea; D010805:Physical Conditioning, Animal; D051381:Rats; D011916:Rats, Inbred F344
chemical_list: D008770:Methylnitrosourea