Volume 87, Issue 2, February (2002), pp. 147-155 © The Author 2002
doi:10.1079/BJN2001489

Medline/PubMed Citation | Related Articles in PubMed | Download to Citation Matcher  

Pancreatic islet insulin secretion and metabolism in adult rats malnourished during neonatal life

Francisco B. Barbosa, Kirsten Capito*, Hans Kofod and Peter Thams
Department of Medical Biochemistry and Genetics, The Panum Institute, University of Copenhagen, Copenhagen, Denmark

 (Received 9 April 2001–Revised 13 August 2001–Accepted 5 October 2001)

Pancreatic islets were isolated from rats that had been nursed by dams fed with a control or an 8·7 % protein diet during the first 12 d of the lactation period. Glucose-induced insulin secretion from islets in the 8·7 % protein group was reduced 50 %. The islet insulin and DNA content were similar, whereas the pancreatic insulin content was reduced by 30 % in the rats fed 8·7 % protein. In order to elucidate the mechanism responsible for the attenuation of insulin secretion, measurements were performed of the activity of several islet enzymes that had previously been supposed to be involved in the coupling of glucose stimulation to insulin secretion. Islet glucose oxidation was unaffected, but glucose-stimulated hydrolysis of phosphatidylinositol was reduced by one-third in the islets of rats fed 8·7 % protein. The activity of mitochondrial glycerophosphate dehydrogenase was similar in islets of rats fed the 8·7 % protein diet and those fed the control diet. The activity of Ca-independent phospholipase A₂ was increased fourfold in the islets of rats fed 8·7 % protein. It is concluded that impairment of glucose-induced insulin secretion in rats fed a low-protein diet may be caused by attenuation of islet phosphatidylinositol hydrolysis, and it is tentatively suggested that the increased activity of Ca-independent phospholipase A₂ in islets of rats fed a low-protein diet may participate in the stimulation of apoptosis.

Keywords:
Protein malnutrition: Pancreatic islet metabolism: Insulin secretion: Phosphoinositides: Phospholipase A₂: Glycerophosphate dehydrogenase