Calcified Tissue International

, Volume 34, Issue 1, pp 506–509 | Cite as

Chloroquine, hydroxystilbamidine, and dapsone inhibit resorption of fetal rat bone in organ culture

  • Gabriel Eilon
  • Lawrence G. Raisz
Laboratory Investigations


Three potential inhibitors of lysosomal enzyme release, chloroquine, hydroxystilbamidine, and dapsone were tested for their effects on the release of previously incorporated45Ca and beta (β)-glucuronidase from fetal rat long bones cultured in a chemically defined medium. At concentrations of 10−5 to 10−8M, all three agents were able to inhibit the stimulation of bone resorption by parathyroid hormone (PTH) or prostaglandin E2 (PGE2). Inhibition was seen at concentrations which did not alter the uptake of (3H)-2-deoxy-glucose or the incorporation of (3H)-thymidine in bone. While the inhibitors blocked the stimulation of β-glucuronidase release by PTH and PGE2, they could also cause a direct increase in total β-glucuronidase content and release. Hence the usual strong correlation between the release of β-glucuronidase and45Ca was no longer seen in the presence of inhibitors. These data indicate that chloroquine, hydroxystilbamidine, and dapsone are potent inhibitors of bone resorption which may act by blocking the release of lysosomal enzymes in cells stimulated by PTH or PGE2, but may have a different effect on other cell populations.

Key words

Lysosomal enzymes Bone resorption Chloroquine Dapsone Hydroxystilbamidine 


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Copyright information

© Springer-Verlag 1982

Authors and Affiliations

  • Gabriel Eilon
    • 1
  • Lawrence G. Raisz
    • 1
  1. 1.Division of Endocrinology and Metabolism, Department of MedicineThe University of Connecticut Health CenterFarmingtonUSA

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