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Determination of cellular retinol‐binding protein in human hepatocellular and colorectal carcinomas by radioimmunoassay
Author(s) -
OKUNO MASATAKA,
KATO MICHIMASA,
KANAI MASAMITSU,
MUTO YASUTOSHI
Publication year - 1987
Publication title -
journal of gastroenterology and hepatology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.214
H-Index - 130
eISSN - 1440-1746
pISSN - 0815-9319
DOI - 10.1111/j.1440-1746.1987.tb00182.x
Subject(s) - retinol , radioimmunoassay , retinol binding protein , hepatocellular carcinoma , vitamin , medicine , antibody , immunoassay , affinity chromatography , isoelectric focusing , endocrinology , pathology , biochemistry , biology , enzyme , immunology
A study was conducted to determine the tissue levels of cellular retinol‐binding protein (CRBP), serum retinol‐binding protein (RBP) and retinoids in hepatocellular carcinoma (HCC) and in colorectal adenocarcinoma. CRBP, which has a molecular weight of 14 900 daltons and an isoelectric point of 4.9, was purified from human liver. An antihuman CRBP antibody was raised in the turkey and further purified by immunosorbent affinity chromatography on CRBP‐coupled Sepharose column. A radioimmunoassay for CRBP using this antibody was established. RBP was measured by an enzyme immunoassay and retinoids were measured by high‐performance liquid chromatography analysis. Retinol levels in liver tumours were significantly decreased compared with those in respective non‐cancerous adjacent tissues. Retinyl ester levels in liver tumours were also significantly decreased compared with those in the adjacent tissues. CRBP levels in liver tumours were significantly decreased compared with those in the adjacent tissues, whereas no significant difference was observed in the CRBP level between the colon tumours and adjacent colon tissues. RBP levels in liver tumours were also significantly decreased compared with those in the adjacent tissues. The decreased CRBP levels in liver tumours may, at least in part, account for the local deficiency of retinol in HCC, whereas colon tumours may grow independently, regardless of retinol status.