title: Inhibition of bone resorption in vitro by serine-esterase inhibitors.
abstract: The effect of two synthetic serine esterase inhibitors, N-alpha-dansyl(p-guanidino)phenylalaninepiperidine hydrochloride (I 2581) and D-phenylalanyl-L-prolyl-L-arginine chloromethyl ketone (D-Phe-Pro-Arg-CH2Cl), on bone resorption in organ cultured mouse calvaria from neonatal mice has been examined. Mineral mobilization was assessed by analyzing the release of 45Ca, stable calcium (Ca2+) and inorganic phosphate (Pi). Organic matrix degradation was studied by analyzing the release of 3H from [3H]proline-labelled bones, and by quantifying the amounts of hydroxyproline in bone after culture. It was found that I 2581, at and above 30 mumol/l, dose-dependently inhibited 45Ca release induced by thrombin, parathyroid hormone (PTH), prostaglandin E2 and 1-alpha-hydroxyvitamin D-3. I 2581 (50 mumol/l) inhibited PTH-stimulated release of 3H from [3H]proline-labelled bones, and this effect was reversible after withdrawal of I 2581. I 2581 (50 mumol/l) inhibited the release of Ca2+, Pi, beta-glucuronidase and beta-N-acetylglucosaminidase in bones stimulated by PTH and 1-alpha-hydroxyvitamin D-3, without affecting the release of lactate dehydrogenase. In parallel, I 2581 decreased PTH and 1-alpha-hydroxyvitamin D-3 induced reduction of hydroxyproline levels in bones after culture. I 2581 (50 mumol/l) did not affect the basal release of 45Ca, Ca2+, beta-glucuronidase and beta-N-acetylglucosaminidase, nor the basal amounts of hydroxyproline in bones after culture. D-Phe-Pro-Arg-CH2Cl (100 mumol/l) significantly inhibited PTH- and PGE2-induced release of 45Ca without affecting basal release of radioactive calcium. These data indicate that activation of serine proteinase(s) may be a necessary step in the mechanism of action of several stimulators of bone resorption.
authors.affiliation: Department of Oral Pathology, University of Umeå, Sweden.
authors.forename: U H
authors.initials: UH
authors.lastname: Lerner
authors.forename: G T
authors.initials: GT
authors.lastname: Gustafson
mesh_terms: D000118:Acetylglucosaminidase / Q000378:metabolism; D000590:Amino Acid Chloromethyl Ketones / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001862:Bone Resorption / Q000187:drug effects*; D001842:Bone and Bones / Q000187:drug effects / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D004950:Esterases / Q000037:antagonists & inhibitors*; D005966:Glucuronidase / Q000378:metabolism; D006887:Hydroxycholecalciferols / Q000494:pharmacology; D006909:Hydroxyproline / Q000378:metabolism; D007770:L-Lactate Dehydrogenase / Q000378:metabolism; D051379:Mice; D009924:Organ Culture Techniques; D010281:Parathyroid Hormone / Q000494:pharmacology; D010649:Phenylalanine / Q000031:analogs & derivatives* / Q000494:pharmacology; D010710:Phosphates / Q000378:metabolism; D010880:Piperidines / Q000494:pharmacology*
chemical_list: D000590:Amino Acid Chloromethyl Ketones; D006887:Hydroxycholecalciferols; D010281:Parathyroid Hormone; D010710:Phosphates; D010880:Piperidines; D010649:Phenylalanine; C054648:N-dansyl-(1,4-guanidino)phenylalanine piperdide; D007770:L-Lactate Dehydrogenase; D004950:Esterases; C022635:serine esterase; D005966:Glucuronidase; D000118:Acetylglucosaminidase; C040308:phenylalanyl-prolyl-arginine-chloromethyl ketone; D006909:Hydroxyproline; D002118:Calcium; C008088:alfacalcidol