Rat Pancreatic β-Cells in Protein Deficiency: A Study Involving Morphometric Analysis and Alloxan Effect

Abstract

The possible cause(s) of impaired glucose tolerance in protein-calorie malnutrition was studied. The beta-cell mass was morphometrically determined and the sensitivity to alloxan was characterized in rats fed ad libitum a 4% protein diet, pair-fed or fed ad libitum a 20% protein diet. The percentage of beta-cells in the pancreas was neither affected by protein deficiency nor influenced by caloric intake. However, the diabetogenicity of alloxan was greatly reduced in protein-malnourished rats. This reduction in diabetogenicity by alloxan was partially reversed by feeding animals with sulfhydryl compound. These results suggest that decreased insulin secretion in protein malnutrition is not due to a reduction in beta-cell number.

Alteration of the counterregulatory hormones in the conscious rat after protein-energy restriction

“…In the same experimental rat model we have previously reported that the in vivo insulin response to glucose was very poor [5] in agreement with previous reports in similar models [3,15,17,18], and that this impairment of insulin release was related at least in part to intrinsic abnormality(ies) of the pancreatic betacells [5,17]. It is also notable that in the same rat model, protein-energy malnutrition has been reported to cause a diminution of beta-cell mass [19] and that such beta-cell atrophy is a feature rather typical of protein shortage [19][20][21][22]. Under basal postabsorptive conditions and in the face of drastically lowered plasma insulin levels, protein-energy restricted rats maintained low basal plasma glucose levels.…”

Effect of a Low Protein Diet during Pregnancy on the Fetal Rat Endocrine Pancreas

“…They also observed a decrease in the number of large islets, in the islet diameter, and in endocrine volume when compared to controls. Similar ly, after the same treatment, Dixit and Kaung [1985] came to the same conclusion. Furthermore, the results of de Gasparo et al [1978] highlight the role of the amino acids for the proliferation of the fetal B cells.…”

“…A control group of virgin female Wistar rats re ceived a diet containing 20% protein [Weinkove et al, 1977;Dixit and Kaung, 1985;Rodrigues et al, 1985), and a LP group received an isocaloric diet con taining 8% protein (table 1). The females were caged with males overnight and coitus was determined by inspection of vaginal smears; y 0 of gestation being the first day after coitus.…”

Changes of Islet Size and Islet Size Distribution Resulting from Protein‐Malnutrition in Lean (Fa/Fa) and Obese (fa/fa) Zucker Rats

“…Although attenuation of islet size/volume with low-protein feeding has previously been reported in lean rats (3,13,21,29), this is the first study to report similar changes in P-cell mass in obese rats fed low protein. The attenuation of islet sizeholume with protein deficiency might be related to a decrease in islet proliferation.…”