Continuous treatment with a low-dose β-agonist reduces bone mass by increasing bone resorption without suppressing bone formation

Calcif Tissue Int. 2011 Jan;88(1):23-32. doi: 10.1007/s00223-010-9421-9. Epub 2010 Sep 30.


The sympathetic nervous system regulates bone remodeling through the β-adrenergic receptor (β-AR). However, the systemic roles of adrenergic actions on bone remodeling through the β-AR are largely unknown. In this study, we examined the dose effect of continuous treatment with isoprenaline, a nonspecific β-AR agonist, on bone remodeling. Male C57BL/6J mice were intrasubcutaneously administrated with four different doses (5, 25, 50, or 100 μg/g daily) of isoprenaline or vehicle using an osmotic pump for 2 weeks. The region of high-turnover cancellous bone was analyzed by microcomputed tomography (μCT). Continuous isoprenaline treatment caused a ~35.7% decline in the femoral cancellous bone volume fraction (BV/TV) at all doses (5-100 μg/g daily). Furthermore, continuous isoprenaline treatment weakened the bone mechanical properties in the trunk of lumbar vertebra 4 (L4). These parameters did not show significant differences between doses. Histomorphometric analysis revealed that isoprenaline doses of 50 μg/g daily or less did not significantly inhibit bone formation parameters, such as bone formation rate (BFR) and mineral surface/bone surface (MS/BS). Only the highest dose (100 μg/g daily) of isoprenaline significantly inhibited BFR and MS/BS. On the other hand, osteoclast number/bone surface (Oc.N/BS) was enhanced approximately 2.4-fold and osteoclast surface/bone surface (Oc.S/BS) was increased 2.0-fold by all doses of continuous isoprenaline treatment. The osteoclast parameters plateaued at the lowest dose (5 μg/g daily) of continuous isoprenaline treatment. These results indicate that chronic stimulation of β-AR with low-dose agonist treatment induces bone loss mainly via enhanced bone resorption.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenergic beta-Agonists / pharmacology*
  • Animals
  • Bone Resorption / chemically induced*
  • Bone Resorption / pathology
  • Bone and Bones / anatomy & histology
  • Bone and Bones / diagnostic imaging
  • Bone and Bones / drug effects*
  • Dose-Response Relationship, Drug
  • Down-Regulation / drug effects
  • Drug Evaluation, Preclinical
  • Isoproterenol / pharmacology
  • Male
  • Mice
  • Mice, Inbred C57BL
  • Organ Size / drug effects
  • Osteogenesis / drug effects*
  • Osteogenesis / physiology
  • Time Factors
  • Up-Regulation / drug effects
  • X-Ray Microtomography


  • Adrenergic beta-Agonists
  • Isoproterenol