Endocrinology, Vol 123, 1456-1460, Copyright © 1988 by Endocrine Society

ARTICLES

Characterization of insulin-like growth factor II peptides secreted by explants of neonatal brain and of adult pituitary from rats

RP Shiu and JA Paterson
Department of Physiology, Faculty of Medicine, University of Manitoba, Winnipeg, Canada.

This study compares the molecular characteristics of the insulin-like growth factor II (IGF-II) peptides synthesized and secreted by explants of neonatal brain and adult pituitary of rat to those produced by the Buffalo rat liver cell line (BRL-3A). Metabolic labeling, followed by immunoprecipitation and sodium dodecyl sulfate polyacrylamide gel electrophoresis revealed that the rat brain and liver cells synthesized and secreted the following immunoreactive IGF-II peptides: 19, 11, 10, and 8.7 kilodaltons (kd), whereas the rat pituitary secreted the 10 and 8.7 kd peptides. However, the brain and pituitary explants failed to secrete the mature 7.5 kd IGF-II peptide which was a major species secreted by the liver cells. In the brain and pituitary, the predominant form of IGF-II peptide secreted was the 8.7 kd. This result suggests that 1) different mechanisms of processing of the IGF-II precursor and/or the preferential translation of different messenger RNA (mRNA) species may exist in different cell types, and 2) the 8.7 kd IGF-II peptide may be the biologically relevant molecule in the central nervous system of the rat.

This article has been cited by other articles:

				S. J. Duguay, Y. Jin, J. Stein, A. N. Duguay, P. Gardner, and D. F. Steiner Post-translational Processing of the Insulin-like Growth Factor-2 Precursor. ANALYSIS OF O-GLYCOSYLATION AND ENDOPROTEOLYSIS J. Biol. Chem., July 17, 1998; 273(29): 18443 - 18451. [Abstract] [Full Text] [PDF]