Expression of the vasopressin and gastrin-releasing peptide genes in small cell lung carcinoma cell lines.

Various polypeptide hormones including vasopressin (VP) and gastrin-releasing peptide (GRP) are produced by small cell lung carcinomas (SCLC). VP as well as GRP have mitogenic effects on several cell types and are proposed to be autocrine growth factors. In this study the presence of VP mRNA, oxytocin (OT) mRNA and GRP mRNA was investigated in cell lines derived from SCLCs. Out of 26 cell lines 3 contained low amounts of VP mRNA (GLC-8, SCLC-21H and NCI-H345) and 7 contained abundant GRP mRNA (GLC-16, GLC-1-M13, SCLC-22H, NCI-H249, NCI-H345, NCI-H449 and NCI-H450). The GRP mRNA-containing cell lines belong to the classic SCLC type, whereas VP mRNA was found in two classic and one variant cell line. None of the SCLC cell lines contained detectable levels of OT mRNA. Of the three VP-expressing SCLC cell lines, GLC-8 had the highest level of VP mRNA. Both the length of the transcript and the hybridization with different probes containing exons A and C of the VP gene suggest that the detected transcript is a normal VP messenger. SCLC GLC-8 contained low levels of VP immunoreactivity and VP receptors. In GLC-8 an autocrine role of VP may be suspected.