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Assessment of protein synthesis and cellular proliferation in long‐lived crowded litter mice
Author(s) -
Drake Joshua C.,
Peelor Fredrick F.,
Biela Laurie M.,
Miller Richard A.,
Hamilton Karyn L.,
Miller Benjamin F.
Publication year - 2013
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.27.1_supplement.1202.25
Subject(s) - weaning , litter , dna synthesis , protein biosynthesis , medicine , endocrinology , cytosol , biology , chemistry , dna , andrology , biochemistry , ecology , enzyme
Increasing the number of pups prior to weaning (“crowded litter” or CL) increases the lifespan of mice. In previous studies with caloric restriction, rapamycin feeding, and Snell dwarf mice, we have described the general phenomenon that DNA synthesis is decreased and mitochondrial (mito) protein synthesis is maintained, though this varies by tissue and model. Therefore, we hypothesized that CL mice would also have decreased DNA synthesis and maintained mito protein synthesis. UM‐HET3 mice were housed as litters of 8 (CON) or 12 (CL) prior to weaning. At 20 days of age pups were weaned onto a normal chow diet. At 4 months of age 4 CON and 4 CL animals had their drinking water supplemented with 8% deuterium oxide for 2 weeks to determine fraction of new total, cytosolic, and mito proteins, and fraction of new DNA. Protein synthesis was not statistically different in any tissue or fraction assessed. DNA synthesis was significantly greater in CL skeletal muscle (Con = 0.024±0.003, CL = 0.037±0.004), tended to be greater in heart (p=0.08; Con = 0.047±0.003, CL = 0.066±0.018), but did not differ in liver. CL mice were studied at a younger age than our previous investigations, and thus we conclude that either: 1) long‐lived models have a previously unrecognized increase in proliferation at young ages, or 2) CL mice are long‐lived through different mechanisms than our previously studied models.