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H‐Pro‐[ 3 H]Leu‐Gly‐NH 2 : Plasma Profile and Brain Uptake Following Subcutaneous Injection in the Rat
Author(s) -
Verhoef J.,
Prins A.,
Veldhuis H. D.,
Witter A.
Publication year - 1982
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1982.tb05359.x
Subject(s) - metabolite , chemistry , subcutaneous injection , trichloroacetic acid , peptide , tripeptide , high performance liquid chromatography , pharmacology , brain tissue , metabolism , chromatography , biochemistry , endocrinology , medicine
Following subcutaneous injection of the tripeptide H‐Pro‐[ 3 H]Leu‐Gly‐NH 2 ([ 3 H]PLG) in rats, the profile of intact peptide and its radioactively labeled metabolites was examined both in plasma and in brain tissue. [ 3 H]PLG and metabolites were determined in trichloroacetic acid extracts by reverse‐phase paired‐ion HPLC. Maximal plasma levels of unmetab‐olized PLG were reached 6–8 min after administration, after which they decreased with an elimination half‐life of 20 min. The uptake of [ 3 H]PLG in the brain ranged from 0.0013% to 0.0017% of the administered dose per g tissue at 5–30 min following subcutaneous injection. After comparing these results with our previous findings with intravenous injection of [ 3 H]PLG, it seemed likely that the subcutaneous route of administration might be more effective in eliciting CNS effects of PLG than the intravenous route of administration. The metabolite profiles in plasma and brain point to an initial cleavage of PLG at the NH 2 ‐terminal side and a very rapid degradation of the peptide intermediate H‐Leu‐Gly‐NH 2 .