Pharmacokinetics and disposition of recombinant human osteoprotegerin (rhOPG) after intravenous administration in female fischer rats

Abstract

1. Osteoprotegerin (OPG) is a secreted member of the tumour necrosis factor receptor (TNFR) family that leads to the suppression of the differentiation, activation and survival of osteoclasts. The objective was to investigate the in vivo pharmacokinetics and tissue distribution of full-length recombinant human OPG (rhOPG) as well as its clearance mechanism using ¹²⁵I-labelled protein (¹²⁵I-rhOPG) after intravenous administration to female Fischer rats.

2. ^{2. 125}I-rhOPG was rapidly and predominantly distributed to the liver after dosing (3 mg kg⁻¹). Immunohistochemical analysis indicated that rhOPG was located in the sinusoids of the liver.

3. The hepatic uptake of ¹²⁵I-rhOPG (0.01 mg kg⁻¹) was partly regulated under a saturable process. Pre-dosing of some sulfated glycans (20 mg kg⁻¹), especially dextran sulfate, heparin and fucoidan, markedly inhibited the hepatic uptake of ¹²⁵I-rhOPG. The clearance of ¹²⁵I-rhOPG was markedly reduced by the conjugation of dextran sulfate.

4. The results suggested that the hepatic clearance of ¹²⁵I-rhOPG was mainly mediated by the interaction with glycosaminoglycans.

Keywords::

• Osteoprotegerin
• pharmacokintics
• tissue distribution
• hepatic uptake clearance
• glycosaminoglycan

Acknowledgements

The authors would like to thank Dr Kenichi Sudo for helpful insights.

Declaration of interest: The authors report no conflicts of interest. The authors alone are responsible for the content and writing of the paper.