Hepatic production of insulin-like growth factors in normal and diseased liver.

BACKGROUND/AIMS: IGF-I levels are reduced in cirrhotic patients. However, it is not known whether this decreased level is the result of reduced hepatic production or modified bioavailability secondary to decreased binding proteins. We determined the hepatic production of IGF-I and IGF-II and their receptors in normal and diseased liver. METHODOLOGY: Twenty-five patients included, 11 controls with normal liver and 14 with either chronic hepatitis or cirrhosis. mRNA for IGF-1, IGF-II and their receptors were measured. Immunohistochemical staining was performed to localize the IGF-producing cells. RESULTS: In 11 normal livers, the IGF-I mRNA levels were 4.95 +/- 1.8; in the 14 diseased livers, the levels were 1.22 +/- 0.69 (p < 0.001). IGF-II mRNA levels were 3.78 +/- 1.45 for the control and 5.11 +/- 2.15 in the diseased livers (NS). IGF-I receptor levels were 1.15 +/- 0.83 in the normal and 0.31 +/- 0.22 in the liver disease group (p < 0.05). There was no statistical difference between the two groups for IGF-II receptor. CONCLUSIONS: Patients with chronic liver disease have a significant reduction in their hepatic production of IGF-I, whereas IGF-II tends to be elevated. Treatment with recombinant IGF-I in patients with metabolic or endocrine complications of cirrhosis might prove useful.

Relative expression and localization of the insulin-like growth factor system components in the fetal, child and adult intestine.

BACKGROUND: The insulin-like growth factors (IGFs) are important in the development and maintenance of the gastrointestinal tract. OBJECTIVES: To compare the expression of IGFs and their receptors in the stomach and duodenum of the fetus, the child and the adult. To identify the cells mainly responsible for the production of the members of the IGF system. METHODS: Tissue was obtained from fetus after abortion and from children and adults during diagnostic endoscopy and biopsy. The expression of the IGFs and their receptors was estimated by an RNAse protection assay and sections were stained with antisera to the components of IGF system. RESULTS: The tissues from the stomach and the duodenum expressed the two IGFs and their receptors at all stages of life. The fetal IGF receptors I and II, were approximately ten times higher than in the child and IGF-II was five times higher. Immunohistochemical staining showed the components of the IGF system to be localized to the gastric glands and to the basotlateral border of the gastric epithelial cells. In the duodenum, they were concentrated at the apical portion of the epithelial tissue. They could also be identified in ganglion cells and nerves. CONCLUSIONS: The IGFs and their receptors in the stomach and duodenum are expressed in all age groups and mostly are highest in the fetus. The IGF system proteins were located in the gastric glands and epithelium and in the apical portion of the villous epithelium of the duodenum.