A Takagi1, Y Yabe, Y Oka, K Sawai, Y Takakura, M Hashida. 1. Department of DDS Research, Novel Pharma Research Laboratories, Yamanouchi Pharmaceutical Co., Ltd., Ozumi Yaizu, Shizuoka, Japan.
Abstract
PURPOSE: To clarify the mechanism of the renal clearance of recombinant human interleukin- 11 (rhIL- 1), we investigated the renal disposition characteristics of rhIL-11 in the perfused rat kidney. METHODS: The disposition characteristics of (111)In-labeled rhIL-11 were analyzed using a single-pass indicator dilution technique and statistical moment analysis in the perfused rat kidney under filtering and nonfiltering conditions. RESULTS: Steady-state distribution volume (Vd) calculated from the venous outflow patterns of rhIL-11 at the doses of 0.3 to 10 microg/kidney was between 0.35 and 0.40 ml/g kidney. However, Vd at the highest dose decreased to a value almost identical to that of bovine serum albumin, suggesting that there is a reversible and saturable interaction between the capillary wall and rhIL-11 molecule. In filtering kidney, a remarkable accumulation of rhIL-11 was observed while its urinary excretion was highly restricted at all doses. In nonfiltering kidney, rhIL-11 showed a decreased but still significant renal uptake. Taken together, the marked renal uptake of rhIL-11 may be explained by both efficient tubular reabsorption and significant uptake from the capillary side. These processes were not saturable within the tested dose range. These characteristics of rhIL-11 are likely based on non-specific electrostatic interaction with the tissues due to its cationic charge in the cytokine. CONCLUSIONS: The renal disposition processes of rhIL-11 were clarified at organ level in a quantitative manner. These findings agree well with previous observations in an in vivo disposition study in mice.
PURPOSE: To clarify the mechanism of the renal clearance of recombinant humaninterleukin- 11 (rhIL- 1), we investigated the renal disposition characteristics of rhIL-11 in the perfused rat kidney. METHODS: The disposition characteristics of (111)In-labeled rhIL-11 were analyzed using a single-pass indicator dilution technique and statistical moment analysis in the perfused rat kidney under filtering and nonfiltering conditions. RESULTS: Steady-state distribution volume (Vd) calculated from the venous outflow patterns of rhIL-11 at the doses of 0.3 to 10 microg/kidney was between 0.35 and 0.40 ml/g kidney. However, Vd at the highest dose decreased to a value almost identical to that of bovine serum albumin, suggesting that there is a reversible and saturable interaction between the capillary wall and rhIL-11 molecule. In filtering kidney, a remarkable accumulation of rhIL-11 was observed while its urinary excretion was highly restricted at all doses. In nonfiltering kidney, rhIL-11 showed a decreased but still significant renal uptake. Taken together, the marked renal uptake of rhIL-11 may be explained by both efficient tubular reabsorption and significant uptake from the capillary side. These processes were not saturable within the tested dose range. These characteristics of rhIL-11 are likely based on non-specific electrostatic interaction with the tissues due to its cationic charge in the cytokine. CONCLUSIONS: The renal disposition processes of rhIL-11 were clarified at organ level in a quantitative manner. These findings agree well with previous observations in an in vivo disposition study in mice.
Authors: T Uchida; K Aoyama; K Mori; T Usui; T Watanabe; Y Takariki; N Asahara; M Hirose; T Kimura; M Tateishi; S Higuchi Journal: Eur J Drug Metab Pharmacokinet Date: 1998 Jul-Sep Impact factor: 2.441