Corticotrophin-like intermediary lobe peptide as a marker of alternate pro-opiomelanocortin processing in ACTH-producing non-pituitary tumours.
In order to evaluate which of human (h) corticotrophin-like intermediary lobe peptide (CLIP) or h beta-melanocyte stimulating hormone5-22 (h beta MSH5-22) was the better marker of alternate pro-opiomelanocortin (POMC) processing, both peptides were simultaneously sought in the same tissue extracts from a normal human pituitary, six corticotrophic adenomas, and four non-pituitary tumours responsible for an ectopic ACTH syndrome. Human CLIP was detected using a combination of gel exclusion chromatography and two different radioimmunoassays (RIAs): a mid-ACTH RIA which recognized ACTH but not CLIP, and a COOH-ACTH RIA which recognized both molecules. Human beta MSH5-22 had been measured previously. Neither hCLIP nor h beta MSH5-22 were detected in the normal or tumoural pituitaries. The four non-pituitary tumours, in contrast, contained both peptides; the hCLIP and h beta MSH5-22 ratios (CLIP/CLIP + ACTH and h beta MSH5-22/h beta MSH5-22 + h gamma LPH) ranged from 40 to 94% and from 24 to 46%, respectively. In a given tissue the hCLIP ratio was always higher than the h beta MSH5-22 ratio. hCLIP is therefore the better marker of alternate POMC processing.
Vieau
D
D
Centre de Recherches sur les Maladies Endocriniennes, Hôpital Cochin, Paris, France.
Massias
J F
JF
Girard
F
F
Luton
J P
JP
Bertagna
X
X
D000182:ACTH Syndrome, Ectopic / Q000378:metabolism*; D000236:Adenoma / Q000378:metabolism; D000324:Adrenocorticotropic Hormone / Q000032:analysis*; D014408:Biomarkers, Tumor / Q000032:analysis*; D001984:Bronchial Neoplasms / Q000378:metabolism; D002276:Carcinoid Tumor / Q000378:metabolism; D002850:Chromatography, Gel; D053497:Corticotropin-Like Intermediate Lobe Peptide; D006801:Humans; D009074:Melanocyte-Stimulating Hormones / Q000032:analysis; D009384:Paraneoplastic Endocrine Syndromes / Q000378:metabolism*; D010446:Peptide Fragments / Q000032:analysis*; D010911:Pituitary Neoplasms / Q000378:metabolism; D011333:Pro-Opiomelanocortin / Q000378:metabolism*; D011863:Radioimmunoassay; D013953:Thymus Neoplasms / Q000378:metabolism
D014408:Biomarkers, Tumor; D010446:Peptide Fragments; D053497:Corticotropin-Like Intermediate Lobe Peptide; D011333:Pro-Opiomelanocortin; D000324:Adrenocorticotropic Hormone; D009074:Melanocyte-Stimulating Hormones