Effects of age on plasma levels of calcium-regulating hormones and bone status in male SAMP8 mice.
This study was undertaken to examine whether the plasma levels of calcium-regulating hormones and bone status alter with age in male senescence accelerated mice (SAM), SAMP8. Age-matched senescence-resistant mice, SAMR1, were used as controls. The blood and femur samples were collected at 2.5 months of age (M) and then monthly from 3 to 12 M for physicochemical analyses, biochemical analyses, and the determination of hormones by radioimmunoassay. With advancing age, the plasma calcitonin (CT) levels decreased progressively, and the plasma parathyroid hormone (PTH) and 1,25-dihydroxycholecalciferol (1,25(OH)2D3) levels increased in both SAMR1 and SAMP8. The plasma calcium concentrations were maintained within a narrow range throughout the experimental period, while the plasma phosphorus (P) concentrations decreased with age in both strains. In contrast to SAMR1, the curves of age-related changes in the plasma CT levels and P concentrations were lower, and those in the plasma PTH levels were higher in SAMP8. The femoral bone densities and calcium contents increased gradually with age from the beginning of the experiment and peaked at 6 M in both strains, then declined. Those peaks were lower in SAMP8 than in SAMR1. These results indicate that the male SAMP8 develops osteoporotic signs earlier than SAMR1, and is proved to be a satisfactory animal model for longitudinal studies related to osteoporosis for men.
Chen
Chun-Chi
CC
Department of Animal Science, Tunghai University, Taichung, Taiwan.
Wang
Ming-Fu
MF
Liu
Mei-Hui
MH
Lin
Wu-Ting
WT
Yang
Shyi-Kuen
SK
D019588:Aging, Premature / Q000503:physiopathology*; D000469:Alkaline Phosphatase / Q000097:blood / Q000378:metabolism; D000818:Animals; D015519:Bone Density; D001842:Bone and Bones / Q000378:metabolism*; D002116:Calcitonin / Q000097:blood*; D002117:Calcitriol / Q000097:blood*; D002118:Calcium / Q000097:blood / Q000378:metabolism*; D005269:Femur / Q000378:metabolism; D008297:Male; D051379:Mice; D008815:Mice, Inbred Strains; D009994:Osmolar Concentration; D010281:Parathyroid Hormone / Q000097:blood*; D010758:Phosphorus / Q000097:blood
D010281:Parathyroid Hormone; D010758:Phosphorus; D002116:Calcitonin; D000469:Alkaline Phosphatase; D002117:Calcitriol; D002118:Calcium