Insulin-like growth factors (IGF) in liver disease: differential changes of IGF-I and IGF-II

IGFs are growth hormone-dependent, serum growth factors which are secreted primarily by liver, although other tissues contribute. We have measured IGF levels in serum of patients with primary biliary cirrhosis (n = 28), primary sclerosing cholangitis (n = 10), and alcohol-induced liver disease (n = 16), and compared them to a group of healthy controls (n = 25). Serum IGF-I as measured by radioimmunoassay was significantly decreased in all patient groups to 30% of control. After acid gel chromatography, IGF-II, measured by radioreceptor assay, was slightly decreased (p less than 0.05) in primary sclerosing cholangitis patients, but not in the other liver disease patients, when compared to the controls. The regression of IGF-II vs IGF-I for primary biliary cirrhosis patients was significant, with r = 0.62, p less than 0.01 (n = 27). The mean ratio of IGF-II/IGF-I was significantly different for histologic stage 2 vs stage 3 vs stage 4 primary biliary cirrhosis patients, but stage 2 was not different from control. We suggest low IGF-I values may reflect compromised hepatocyte function, and secretion of IGF-I and IGF-II may be from different cell populations, or controlled by different mechanisms.