Abstract
A specific sugar-modified peptide has previously been shown to have renal targeting potential in vivo and to have a specific binding site which has been identified in the kidney membrane fraction. In this report, we studied the inhibitory effects of glycosylated derivatives on the binding of [3H]Glc-O-C8-AVP [a glucosylated derivative of Arg8-vasopressin (AVP),Kd = 55 nM] to clarify the structural requirements necessary for renal recognition. Glc-S-C7-Me (octyl β-d-thioglucoside) markedly inhibited the binding, to a much greater extent than Glc-O-C7-Me (octyl β-d-glucoside) and Gal-S-C7-Me (octyl β-d-thiogalactoside). Also, [3H]Glc-S-C7-Me was shown to have a specific binding site on the kidney membrane (Kd = 17 nM, Bmax = 24 pmol/mg protein) rather than the liver membrane and, in addition, Glc-S-C7-Me exhibited effective and selective renal uptake in vivo. To examine the possibility that Glc-S-C7-Me might be of practical use as a renal targeting vector, AVP, tryptamine and 4-nitrobenz-2-oxa-1,3-diazole were modified with Glc-S-C8- and the tissue uptake of the resulting derivatives was evaluated. All of these derivatives showed clear renal targeting potential because the apparent uptake clearance by the kidney was greater than 3 ml/min/g kidney in each case. As far as the AVP derivatives were concerned, derivatives having different numbers of methylene groups were compared with Glc-S-C8-AVP. Glc-S-C11-AVP exhibited increased kidney targeting potential, whereas that of Glc-S-C5-AVP was reduced. These differences suggest that the “alkylglycoside” moiety is important for renal uptake. In addition, these renally targeted derivatives inhibited the binding of [3H]Glc-S-C7-Me to the kidney membrane fraction. Our findings allow us to conclude that the alkylglycoside is a suitable candidate vector for renal targeting.
Footnotes
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Send reprint requests to: Kokichi Suzuki, Pharmaceutical Research Center, Meiji Seika Kaisha Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan.
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↵1 Present address: Pharmaceutical Research Center, Meiji Seika Kaisha, Ltd., 760 Morooka-cho, Kohoku-ku, Yokohama 222-8567, Japan.
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↵2 Present address: New Product Research Laboratories IV, Daiichi Pharmaceutical Co., Ltd., 16-13 Kitakasai 1-chome, Edogawa-ku, Tokyo 134-8630, Japan.
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↵3 Present address: Medicinal Chemistry Research Laboratory, Tanabe Seiyaku Co., Ltd., 2-50 Kawagishi 2-chome, Toda-shi, Saitama 335-8505, Japan.
- Abbreviations:
- AVP
- arginine vasopressin
- Bmax
- maximum binding capacity
- CLup
- uptake clearance
- CLup
- app, apparent uptake clearance
- DCC
- dicyclohexylcarbodiimide
- DMF
- N,N-dimethylformamide
- Gal-S-C7-Me
- octyl β-d-thiogalactoside
- Glc-O-C5-Me
- hexyl β-d-glucoside
- Glc-O-C7-Me
- octyl β-d-glucoside
- Glc-S-C7-Me
- octyl β-d-thioglucoside
- HOCO-C5-NBD
- N-[7-nitrobenz-2-oxa-1,3-diazole-4-yl]aminohexanoic acid
- HOSu
- N-hydroxysuccinimide
- NBD
- 4-nitrobenz-2-oxa-1,3-diazole
- TFA
- trifluoroacetic acid
- HPLC
- high-performance liquid chromatography
- BSA
- bovine serum albumin
- AUC
- area under the curve
- IC50
- 50% inhibitory concentration
- CHAPS
- 3-[cholamidopropyl)dimethylamino]-1-propanesulfonate
- Received April 28, 1998.
- Accepted July 23, 1998.
- The American Society for Pharmacology and Experimental Therapeutics
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