PMID- 1749105
OWN - NLM
STAT- MEDLINE
DCOM- 19920117
LR  - 20190918
IS  - 0021-5082 (Print)
IS  - 0021-5082 (Linking)
VI  - 46
IP  - 4
DP  - 1991 Oct
TI  - [On the mechanisms of retardation of aging and inhibition of mammary 
      tumorigenesis by energy restriction in SHN/C3H F1 female mice].
PG  - 855-66
AB  - Although it has long been known that energy restriction (ER) inhibits tumors and 
      retards aging in rats and mice, its mode of action remains unknown. In rodents, 
      ER alters the rate of age-related changes in physiological indices. Thus, it 
      affects a broad array of age-sensitive parameters. However, present evidence does 
      not indicate which parameters are primary contributors to the deceleration of 
      aging. Compared to fasting or short-term underfeeding, little is known about the 
      metabolic effects of long-term, life-prolonging ER. We thus investigated the 
      effects of ER on hepatic enzyme activities, including drug-metabolizing enzymes 
      and antioxidant enzymes such as superoxide dismutase and catalase. The catalase 
      activity was found to be higher in ER mice than in control mice both at 12 and 24 
      months of age. In accord with the high catalase activity, lipid peroxidation in 
      liver was much less in ER mice than in age matched control mice. 
      beta-Naphthoflavone, known to induce P-450 related enzymes and xanthine oxidase, 
      was given (ip) to increase lipid peroxidation. The ER was found to inhibit lipid 
      peroxidation after beta-naphthoflavone treatment. It was, therefore, concluded 
      that long-term life-prolonging ER increases antioxidant defence, supporting 
      indirectly the free radical theory of aging. It is well known that ER delays 
      puberty in rodents and has a profound influence on serum hormone levels, 
      including those of prolactin (PRL) and thyroid hormones. However, it remains 
      unknown how these effects are produced by ER. We therefore investigated the 
      effects of ER on the islets of Langerhans in the pancreas and on the 
      pituitary-ovarian axis. In the islets of Langerhans, ER was found to increase the 
      density of alpha-cells significantly both in 11- and 67-week-old mice. In the 
      pituitary gland in ER mice, the cellular density of PRL-producing cells 
      diminished significantly while that of growth-hormone-producing cells did not. 
      One of the modes of action of ER on the endocrine system is thus concluded to be 
      mediated by changing cellular population. Since ER decreased PRL-producing cells 
      and PRL plays a key role in mammary tumorigenesis, we investigated whether ER 
      decreased the gene expression of mouse mammary tumor virus (MMTV) in SHN/C3H 
      mice. The SHN strain, which was found to have a new MMTV provirus locus, mtv-4, 
      was used in the study.(ABSTRACT TRUNCATED AT 400 WORDS)
FAU - Koizumi, A
AU  - Koizumi A
AD  - Department of Hygiene, Akita University School of Medicine.
LA  - jpn
PT  - English Abstract
PT  - Journal Article
PT  - Review
PL  - Japan
TA  - Nihon Eiseigaku Zasshi
JT  - Nihon eiseigaku zasshi. Japanese journal of hygiene
JID - 0417457
SB  - IM
MH  - Aging/*physiology
MH  - Animals
MH  - *Diet, Reducing
MH  - *Energy Metabolism
MH  - Female
MH  - Mammary Neoplasms, Experimental/*prevention & control
MH  - Mice
MH  - Mice, Inbred C3H
RF  - 32
EDAT- 1991/10/01 00:00
MHDA- 1991/10/01 00:01
CRDT- 1991/10/01 00:00
PHST- 1991/10/01 00:00 [pubmed]
PHST- 1991/10/01 00:01 [medline]
PHST- 1991/10/01 00:00 [entrez]
AID - 10.1265/jjh.46.855 [doi]
PST - ppublish
SO  - Nihon Eiseigaku Zasshi. 1991 Oct;46(4):855-66. doi: 10.1265/jjh.46.855.