Standardization of insulin secretion from pancreatic islets: validation of a DNA assay

Horm Metab Res. 1985 Nov;17(11):559-61. doi: 10.1055/s-2007-1013606.

Abstract

The use of islet DNA content to standardize insulin secretion rates from pancreatic islets of different sizes has been studied. Isolated intact islets were sorted into 4 size categories and perifused with 22 mM glucose, collecting effluent in 5 min fractions for insulin RIA. DNA content of perifused islets was measured by fluorometric assay, and insulin secretion expressed as pmoles/ug DNA/unit time. For islets with diameters less than 300 u (1) insulin secretion was proportional to islet size; (2) insulin release per islet and islet DNA content were strongly correlated; (3) when expressed as a function of DNA content, insulin secretion from different sized islets was not significantly different. These relationships did not continue for very large islets (above 300 u) suggesting a limiting islet size for insulin secretion in vitro. The data demonstrates that expression of insulin secretion from pancreatic islets with diameters less than 300 u, as a function of their DNA content standardizes secretion irrespective of islet size and number, and should allow direct comparison of secretory responses between different islet tissue preparations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • DNA / analysis*
  • Insulin / metabolism*
  • Insulin Secretion
  • Islets of Langerhans / analysis
  • Islets of Langerhans / cytology
  • Islets of Langerhans / metabolism*
  • Rats

Substances

  • Insulin
  • DNA