Influence of a low calcium and phosphorus diet on the anabolic effect of human parathyroid hormone (1-38) in female rats.
Parathyroid hormone (PTH) or synthetic N-terminal PTH fragments administered intermittently have been established as anabolic agents in animal and human bones. In the present study, the influence of a low calcium diet on the anabolic effect of human PTH(1-38) [hPTH(1-38)] was investigated. Forty-eight 10-week-old female Sprague-Dawley rats were randomly assigned to a diet with a low calcium content (LCa) or a diet with the recommended amount of calcium (RCa). After an adaptation period of 15 days, the rats were randomly assigned to hPTH(1-38) treatment (+LCa/+RCa) or vehicle only (-LCa/-RCa) for an additional 14 days. Total bone mineral density (BMD) values of several bones were determined using quantitative computed tomography and from ratios of ash weight to volume. Biomechanical competence of the fourth lumbar vertebrae and of the right femora was assessed. An anabolic effect could be detected in both PTH-treated groups. However, the bones of the +LCa group showed significantly lower BMD and also a diminished increase in maximal breaking force compared with those of the +RCa group. The study demonstrates that the anabolic effect of hPTH(1-38) is blunted by the LCa diet. This suggests that, during PTH treatment, dietary calcium intake is critical.
Steiner
P D
PD
Institute of Animal Nutrition, Department of Veterinary Physiology, University of Zurich, Zurich, Switzerland.
Forrer
R
R
Kneissel
M
M
Gasser
J A
JA
Thomsen
J S
JS
Mosekilde
L
L
Riond
J L
JL
D000818:Animals; D001696:Biomechanical Phenomena; D015519:Bone Density / Q000187:drug effects; D002136:Calcium, Dietary / Q000097:blood / Q000493:pharmacokinetics*; D004435:Eating; D004734:Energy Metabolism / Q000187:drug effects*; D005260:Female; D005269:Femur / Q000033:anatomy & histology / Q000378:metabolism; D007408:Intestinal Absorption; D008159:Lumbar Vertebrae / Q000033:anatomy & histology / Q000378:metabolism; D008274:Magnesium / Q000097:blood; D009929:Organ Size; D010281:Parathyroid Hormone / Q000097:blood / Q000493:pharmacokinetics*; D010446:Peptide Fragments / Q000097:blood / Q000493:pharmacokinetics*; D016226:Phosphorus, Dietary / Q000097:blood / Q000493:pharmacokinetics*; D051381:Rats; D017207:Rats, Sprague-Dawley; D014807:Vitamin D / Q000031:analogs & derivatives* / Q000097:blood
D002136:Calcium, Dietary; D010281:Parathyroid Hormone; D010446:Peptide Fragments; D016226:Phosphorus, Dietary; C035747:parathyroid hormone (1-38); D014807:Vitamin D; C097949:1,25-dihydroxyvitamin D; D008274:Magnesium