Ogawa K, Ono K, Kurohmaru M, Hayashi Y. Effect of streptozotocin injection on expression of immunoreactive follistatin and βA and βB subunits of inhibin/activin in rat pancreatic islets. Eur J Endocrinol 1995;132:363–9. ISSN 0804–4643
The effect of streptozotocin (STZ) on expression of immunoreactive follistatin and β-subunits of inhibin/activin in pancreatic islets was studied by immunohistochemistry. To localize immunoreactive follistatin in pancreatic islets, two different anti-follistatin sera were used. Anti-follistatin(300–315) serum detects only long-form follistatin, while anti-follistatin(123–134) serum detects both long- and C-terminal truncated short-form follistatin in sodium dodecyl sulfate polyacrylamide gel electrophoresis and immunoblotting. Although an intense reaction with anti-follistatin(123–134) was found in pancreatic B cells, a reaction with anti-follistatin(300–315) was not present in any type of cells. This result suggests that only short-form follistatin is expressed in pancreatic islets. It was confirmed that immunoreaction with anti-βA(1–10)-Tyr serum was found in pancreatic B cells. The anti-βB(1–10)-Tyr reaction was intense in A cells but weak in B cells. These findings suggest that the expression pattern of each β-subunit differs in each type of islet cells. At 2 weeks after STZ injection (65 mg/kg), insulin immunoreaction still remained in B cells, although most pancreatic B cells were destroyed. In contrast, immunoreactions of follistatin and β-subunits in B cells disappeared 24 h after STZ treatment. These results indicate that STZ affects the production of follistatin or β-subunits of inhibin/activin in pancreatic B cells rather than insulin secretion.
Kenji Ogawa, Department of Veterinary Anatomy, Faculty of Agriculture, The University of Tokyo, Bunkyo-ku, Tokyo 113, Japan