Somatomedin C in the pancreas of young and adult,normal and obese,hyperinsulinemic mice |
| |
Authors: | Dr. H. -A. Hansson D. Edwall B. Löwenadler G. Norstedt S. Paleus A. Skottner |
| |
Affiliation: | (1) Department of Histology, University of Göteborg, Göteborg;(2) Center for Biotechnology F 82, Huddinge University Hospital, Huddinge;(3) KabiGen AB, Stockholm, Sweden;(4) KabiVitrum AB, Stockholm, Sweden;(5) Department of Histology, P.O. Box 33 031, S-400 33 Göteborg, Sweden |
| |
Abstract: | Summary Immunocytochemical, immunochemical and RNA-hybridization techniques were used to map the distribution of somatomedin C (Sm-C; insulin-like growth factor I; IGF-I) in the pancreas of young and adult lean and obese mice. The D cells in the islets of Langerhans showed intense cytoplasmic Sm-C immunoreactivity, extending into their processes. Only slight Sm-C immunoreactivity was seen in A and B cells, apparently confined to the plasma membranes. In the exocrine pancreas scattered duct cells were immunopositive. Starvation increased, while feeding decreased the Sm-C immunoreactivity in B cells. RNA-hybridization analyses revealed that roughly the same number of Sm-C mRNA molecules, as calculated per DNA amount in the pancreas, could be demonstrated in young and adult, lean and obese mice. Radioimmunoassay (RIA) determinations of total Sm-C showed that there were about equal concentrations in the pancreas of lean and obese mice. There were marked differences between the liver and the pancreas, in that the RIA Sm-C values for the former were twice those in the latter while, in contrast, the corresponding values for the Sm-C mRNA, i.e. the agent determining the synthesis of Sm-C, were about 100 times higher in the liver as compared to that in the pancreas. We interpret our results as follows: The D cells in the islets form and secrete Sm-C in both young and adult, lean and obese mice, while A and B cells bind, but do not necessarily synthesize this peptide. Our results obtained in vivo on mature pancreatic tissue are in contrast to those obtained in tissue-culture studies on fetal and neonatal islets, in which B cells synthesize Sm-C. |
| |
Keywords: | Insulin-like growth factor I Somatomedin C Hyperinsulinemia Liver Pancreas, endocrine Endocrine cells D cells Mice, hyperinsulinemic: obese (ob/ob), lean (l/l) Mouse l/l |
本文献已被 SpringerLink 等数据库收录! |
|