Abstract
Long-term use of phenytoin for the treatment of epilepsy has been associated with increased thickness of craniofacial bones. The aim of the present study was to evaluate the possibility that low doses of phenytoin are osteogenic in vivo by measuring the effects of phenytoin administration on serum and bone histomorphometric parameters of bone formation in two rat experiments. In the first experiment, four groups of adult male Sprague-Dawley rats received daily I.P. injections of 0, 5, 50, or 150 mg/kg/day of phenytoin, respectively, for 47 days. Serum alkaline phosphatase (ALP) and osteocalcin were increased by 5 and 50 mg/kg/day phenytoin. The increases in osteocalcin and ALP occurred by day 7 and day 21, respectively. The tibial diaphyseal mineral apposition rate (MAR) at sacrifice (day 48) was significantly increased in rats receiving 5 mg/kg/day phenytoin. At a dose of 150 mg/kg/day, the increase in serum ALP, osteocalcin and MAR was reversed. No significant differences in serum calcium, phosphorus, or 1,25(OH)2D3 levels were seen. In a second experiment, three groups of rats received daily I.P. injection of lower doses of phenytoin (i.e., 0, 1, or 5 mg/kg/day, respectively) for 42 days. Phenytoin also did not affect the growth rate or serum calcium, phosphorus, and 25(OH)D3 levels. Daily injection of 5 mg/kg/day phenytoin significantly increased several measures of bone formation, i.e., serum ALP and osteocalcin, bone ALP, periosteal MAR, and trabecular bone volume. However, rats receiving lower doses of phenytoin (i.e., 1 mg/kg/day) did not show significant increases in the serum bone formation parameters. In contrast, metaphyseal osteoblast surface, osteoblast number, osteoid thickness, surface, and volume were all significantly increased in rats treated in 1 mg/kg/day but not with 5 mg/kg/day phenytoin, suggesting that the tibial diaphysis and metaphysis bone formation parameters might have different dose-dependent responses to phenytoin treatment. Administration of the test doses of phenytoin did not significantly affect the histomorphometric bone resorption parameters. In conclusion, these findings represent the first in vivo evidence that phenytoin at low doses (i.e., between 1 and 5 mg/kg/day) is an osteogenic agent in the rat.
This is a preview of subscription content, log in via an institution to check access.
Similar content being viewed by others
References
Christiansen C, Rodbro P, Lund M (1973) Incidence of anticonvulsant osteomalacia and effect of vitamin D: controlled therapeutic trial. Br Med J 4:695–698
Hahn TJ, Hendin BA, Scharp CR, Boisseau VC, Haddad JG (1975) Serum 25-hydroxycalciferol levels and bone mass in children on chronic anticonvulsant therapy. N Engl J Med 292:550–554
Hunter J, Maxwell JD, Stewart DA, Parsons V, Williams R (1971) Altered calcium metabolism in children on anticonvulsants. Br Med J 2:202–204
Richens A, Rowe DJF (1970) Disturbance of calcium metabolism by anticonvulsant drugs. Br Med J 4:73–76
Caspary WF (1972) Inhibition of intestinal calcium transport by diphenylhydantoin in rat duodenum. Naunyn-Schmiedeberg's Arch F Pharmakol 274:146–153
Koch H-U, Kraft D, Von Herrath D, Schaefer K (1972) Influence of diphenylhydantoin and phenobarbital on intestinal calcium transport in the rat. Epilepsia 13:829–834
Hahn TJ, Birge SJ, Scharp CR, Avioli LV (1972) Phenobarbitalinduced alterations in vitamin D metabolism. J Clin Invest 51:741–748
Silver J, Neale G, Thompson GR (1974) Effect of phenobarbitone treatment on vitamin D metabolism in mammals. Clin Sci Mol Med 46:433–448
Reynolds EH (1975) Chronic antiepileptic toxicity: a review. Epilepsia 16:319–352
Kutt H, Solomon GE (1980) Phenytoin: relevant side effects. Adv Neurol 27:435–445
Hahn TJ, Avioli LV (1975) Anticonvulsant osteomalacia. Arch Intern Med 135:997–1000
Villareale ME, Chiroff RT, Bergstrom WH, Gould LV, Wasserman RH, Romano FA (1978) Bone changes induced by diphenylhydantoin in chicks on a controlled vitamin D intake. J Bone Joint Surg 60A:911–916
Christiansen C, Rodbro P, Lund M (1973) Effect of vitamin D on bone mineral mass in normal subjects and in epileptic patients on anticonvulsants: a controlled therapeutic trial. Br Med J 2:208–209
Kattan KR (1970) Calvarial thickening after dilantin medication. Am J Roentgenol Radium Ther Nucl Med 110:102–106
Lefebvre EB, Haining RG, Labbe RF (1972) Coarse facies, calvarial thickening and hyperphosphatasia associated with long-term anticonvulsant therapy. N Engl J Med 286:1301–1302
Kattan KR (1975) Thickening of the heeled pad associated with long-term dilantin therapy. Am J Roentgenol Radium Ther Nucl Med 125:52–56
Seymour RA, Smith DG, Tuenbull DN (1985) The effects of phenytoin and sodium valproate on periodental health of adult epileptic patients. J Clin Periodontal 12:413–419
Sklans S, Taylor RG, Shklar G (1967) Effect of diphenylhydantoin sodium on healing of experimentally produced fractures in rabbit mandibles. J Oral Surg 25:310–319
Hahn TJ, Scharp CR, Richardson CA, Halstead LR, Kahn AJ, Teitelbaum SL (1978) Interaction of diphenyhydantoin (phenytoin) and phenobarbital with hormonal mediation of fetal rat bone resorption in vitro. J Clin Invest 62:406–414
Harris M, Jenkins MV, Wills MR (1974) Phenytoin inhibition of parathyroid hormone-induced bone resorption in vitro. J Pharmacol (Paris) 50:405–408
Jenkins MV, Harris M, Wills MR (1974) The effect of phenytoin on parathyroid extract and 25-hydroxychoecalciferol-induced bone resorption: adenosine 3′, 5′ cyclic monophosphate production. Calcif Tissue Res 16:163–167
Lerner U, Hanstrom L (1980) Influence of diphenylhydantoin on lysosomal enzyme release during bone resorption in vitro. Acta Pharmacol Toxicol 47:144–150
Farley JR, Baylink DJ (1986) Skeletal alkaline phosphatase activity as a bone formation index in vitro. Metabolism 35:563–571
Tanimoto H, Lau K-HW, Nishimoto SK, Wergedal JE, Baylink DJ (1991) Evaluation of the usefulness of serum phosphatases and osteocalcin as serum markers in a calcium depletionrepletion rat model. Calcif Tissue Int 48:101–110
Patterson-Allen P, Brautigan CE, Grindeland RE, Asling CW, Callahan PX (1982) A specific radioimmunoassay for osteocalcin with advantageous species cross-reactivity. Anal Biochem 120:1–7
Fiske CH, SubbaRow Y (1925) Colorimetric determination of phosphorus. J Biol Chem 66:375–400
Price PA, Otsuka AS, Poser JW, Kristaponis J, Raman N (1976) Characterization of a γ-carboxyglutamic acid containing protein from bone. Proc Natl Acad Sci USA 73:1447–1451
Lowry OH, Rosebrough NJ, Farr AL, Randall RJ (1951) Protein measurement with the Folin phenol reagent. J Biol Chem 193:265–275
Baron R, Tross R, Vignery A (1984) Evidence of sequential remodelling in rat trabecular bone: morphology, dynamic histomorphometry, and changes during skeletal maturation. Anat Rec 208:137–145
Brown JP, Malaval L, Chapuy MC, Dalmas PD, Edouard C, Meunier PJ (1984) Serum bone Gla-protein: a specific marker for bone formation in postmenopausal osteoporosis. Lancet 1:1091–1093
Price PA, Williamson MK, Baukol SA (1981) The vitamin K-dependent bone protein and the biological response of bone to 1,25 dihydroxyvitamin D3. In: Veis A, (ed) The chemistry and biology of mineralized connective tissues. Elsevier, North Holland, pp 327–335
Stein GS, Lian JB (1993) Molecular mechanisms mediating proliferation/differentiation interrelationships during progressive development of the osteoblast phenotype. Endocrine Rev 14:424–442
Levy RH (1980) Phenytoin: biopharmacology. Adv Neurol 27:315–321
Dent CE, Richens A, Rowe DJF, Stamp TCB (1970) Osteomalacia with long-term anticonvulsant therapy in epilepsy. Br Med J 4:69–72
Richens A, Rowe DJF (1970) Disturbance of calcium metabolism by anticonvulsant drugs. Br Med J 4:73–76
Author information
Authors and Affiliations
Rights and permissions
About this article
Cite this article
Ohta, T., Wergedal, J.E., Gruber, H.E. et al. Low dose phenytoin is an osteogenic agent in the rat. Calcif Tissue Int 56, 42–48 (1995). https://doi.org/10.1007/BF00298743
Received:
Accepted:
Issue Date:
DOI: https://doi.org/10.1007/BF00298743