{'fraction_non_alphanumeric': 0.0540340488527017, 'fraction_numerical': 0.03552923760177646, 'mean_word_length': 5.595121951219512, 'pattern_counts': {'":': 0, '<': 0, '<?xml version=': 0, '>': 0, 'https://': 0, 'lorem ipsum': 0, 'www.': 0, 'xml': 0}, 'pii_count': 0, 'substrings_counts': 0, 'word_list_counts': {'cursed_substrings.json': 0, 'profanity_word_list.json': 0, 'sexual_word_list.json': 0, 'zh_pornsignals.json': 0}}
Specific binding and clearance of [3H]dynorphin (1–13) in the perfused rat lung: an application of the multiple‐indicator dilution method

Abstract— The clearance and binding of a κ‐selective opioid peptide, dynorphin (1–13), in the perfused rat lung has been examined, using the multiple indicator dilution method. More than 50% of [3H]dynorphin (1–13) entering the pulmonary circulation was eliminated by the lung during a single passage of a tracer dose. By contrast, when a high dose (100 μM) of dynorphin (1–13) was concomitantly injected, [3H]dynorphin (1–13) behaved like [14C]sucrose, an extracellular marker. The kinetic analyses of the pulmonary venous outflow curves of [3H]dynorphin (1–13) and [14C]sucrose at low and high doses of dynorphin (1–13) indicated that the initial uptake rate constant, extraction ratio and distribution volume of [3H]dynorphin (1–13) decreased significantly in the presence of a high concentration of unlabelled dynorphin (1–13). These results suggest that [3H]dynorphin (1–13) is eliminated by a saturable process and binds to a specific binding site in the perfused lung, which may be the κ‐type binding site. The multiple indicator dilution technique, in combination with a moment analysis, was successfully applied to demonstrate the specific binding and clearance of dynorphin (1–13) in the perfused lung.