Distribution and metabolism of dermorphin in rats.

Dermorphin distribution and metabolism were studied in rats injected with high doses of the peptide and with 125I-dermorphin, using RIA methods, HPLC extraction and -counting. Dermorphin rapidly disappeared from plasma (half-life: 1.3 min). In vivo and in vitro experiments demonstrated that the peptide was destroyed in liver and kidney. The highest percent (11%) of injected dermorphin has been found in the bile collected over 1 hour. HPLC analysis showed that bile contained also breakdown products (di, tri, and tetra N-terminal peptide fragments). Reported data suggested that intact dermorphin can be eliminated more slowly than breakdown products.