d-ala(2)-mephe(4)-met(0)-ol-enkephalin and Lung-Neoplasms

Endogenous opioid peptides have been seen to play a role in regulating immunity and tumor growth. This study was carried out to investigate opioid activity in human cancer. We evaluated by radioimmunoassay beta-endorphin plasma levels on blood samples collected at 9.00 a.m. from 121 cancer patients and 42 healthy subjects. In 22 cancer patients and in 12 controls, beta-endorphin circadian rhythm was also investigated. Finally, in 14 cancer patients and in 10 controls GH, PRL, FSH, LH and cortisol serum levels were measured after the administration of a metenkephalin analogue, FK 33-824 (0.3 mg i.v.). No significant differences were seen in beta-endorphin mean levels between cancer patients and normal subjects. Moreover, no differences were found between patients with or without metastases, nor between those with or without chronic pain. beta-Endorphin circadian rhythm appeared to be altered in 16/22 cancer patients, and anomalous hormonal responses to FK 33-824 were seen in 13/14 patients. This study shows an altered opioid activity in human neoplasms, whose clinical significance remains to be determined.

Topics: Adult; Aged; beta-Endorphin; Breast Neoplasms; Circadian Rhythm; D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; Female; Gastrointestinal Neoplasms; Humans; Hydrocortisone; Lung Neoplasms; Male; Middle Aged; Pituitary Hormones, Anterior; Radioimmunoassay

[Met5]Enkephalin and [Leu5]enkephalin, two naturally occurring opioid-like peptides were found to decrease the number of spontaneous pulmonary metastases in C57BL/6J mice implanted in the foot pad with the B16-BL6 melanoma. The number of such metastatic nodules were reduced more than 2-fold. This effect was noted after several different injection schedules. In addition to their effect on metastasis the growth rate of the primary tumor was also decreased by these compounds.

Topics: Animals; D-Ala(2),MePhe(4),Met(0)-ol-enkephalin; Enkephalin, Leucine; Enkephalin, Methionine; Enkephalins; Lung Neoplasms; Melanoma; Mice; Mice, Inbred C57BL; Neoplasm Metastasis