  Shear stress, hormones like parathyroid and mineral elements like calcium
mediate the amplitude of stimulus signal which affects the rate of bone
remodeling. The current study investigates the theoretical effects of different
metabolic doses in stimulus signal level on bone. The model was built
considering the osteocyte as the sensing center mediated by coupled mechanical
shear stress and some biological factors. The proposed enhanced model was
developed based on previously published works dealing with different aspects of
bone transduction. It describes the effects of physiological doses variations
of Calcium, Parathyroid Hormone, Nitric Oxide and Prostaglandin E2 on the
stimulus level sensed by osteocytes in response to applied shear stress
generated by interstitial fluid flow. We retained the metabolic factors
(Parathyroid Hormone, Nitric Oxide, and Prostaglandin E2) as parameters of bone
cell mechanosensitivity because stimulation/inhibition of induced pathways
stimulates osteogenic response in vivo. We then tested the model response in
term of stimulus signal variation versus the biological factors doses to
external mechanical stimuli. Despite the limitations of the model, it is
consistent and has physiological bases. Biological inputs are histologically
measurable. This makes the model amenable to experimental verification.
