| A | B |
|---|
| rickets | expansion of the zone of hypertrophied chondrocytes |
| Fibronectin | Relatively abundant, may help regulate osteoblast differentiation |
| Osteonectin | "Bone connector" may regulate mineralization |
| Thrombospondin | May inhibit bone cell precursors |
| Osteocalcin | Binds calcium |
| Matrix-gla-protein | Inhibits mineralization |
| Bone sialoprotein | Binds to integrins, may assist cancer cells |
| Osteopontin | Increases angiogenesis (makes new blood vessels) which enhances bone resorption in some situations |
| Osteopontin knock-out | Resistance to PTH and removal of ovaries |
| is necessary for bone mineralization. | Vitamin D |
| DHT—dihydrotachysterol | Vitamin D analog no 1-OH needed for activation, does need liver 25-OH |
| 1a-Hydroxycholecalciferol | Vitamin D analog already has 1-OH group |
| Doxercalciferol (1-hydroxyvitamin D2) | Vitamin D analog, does need liver 25-OH |
| 22-oxacalcitriol MOA | suppressor of PTH gene expression, limited action on intestine and bone |
| 22-oxacalcitriol therapeutics | used in chronic renal failure, primary hyperparathyroidism |
| 22-oxacalcitriol indications | low affinity for serum binding protein leads to longer half-life than calcitriol |
| Estrogens | act on osteoblasts to decrease osteoclast recruitment and activation |
| Calcitonin | direct effect on osteoclast to decrease bone resorption |
| Calcitonin | decrease calcium and phosphate reabsorption in kidney |
| Glucocortiocoids | antagonize Vitamin D stimulated intestinal calcium absorption |
| stimulate renal calcium excretion | Glucocortiocoids |
| bisphosphonates indications | Non-hormonal Tx for osteoperosis |
| bisphosphonates MOA | retard formation and dissolution of hydroxyapatite imbibed by osteoclasts |
| bisphosphonate metabolism | metabolized into ATP analog, accumulates in osteoclasts |
| etidronate and tiludronate side effects | impairs cell function and viability, induces apoptosis |
| alendronate MOA | inhibition of protein prenylation important for osteoclast function |
| alendronate | less side effect of decrease bone mineralization |
| gastric irritation common with all bisphosphonates except | etidronate |
| zoledronate toxicity | some renal toxicity |
| plicamycin | cytotoxic antibiotic that also decreases plasma [Ca++] by inhibiting bone resorption |
| cinacalcet MOA | inhibits PTH secretion by lowering the[ Ca++] at which PTH secretion is suppressed |
| cinacalcet | calcimimetic |
| cinacalcet indications | 1' and 2' hyperparathyroidism and hypercalcemia of parathyroid carcinoma |
| thiazide diuretics | inhibit renal calcium stone formation by reducing renal calcium excretion |
| Hypercalcemia tx | Bisphosphonates, calcitonin, plicamycin, gallium nitrate, phosphates, glucocorticoids |
| Osteoporosis tx | Bisphosphonates, calcitonin, vit D analogs, Ca+ supplements, thiazides, intermittent teriparatide |
| Paget’s disease tx | Calcitonin, bisphosphonates |
| Hypoparathyroidism tx | Vitamin D analogs |
| Hyperparathyroidism tx | oxacalcitriol, cinacalcet |
| renal osteodystrophy tx | Vitamin D analogs, phosphate binders |
