Administration of Lupinus albus Gamma Conglutin (Cγ) to n5 STZ Rats Augmented Ins-1 Gene Expression and Pancreatic Insulin Content

Abstract

Several studies support the health-promoting benefits of lupins, particularly lupin proteins. It has been demonstrated that Lupinus albus gamma conglutin (Cγ) protein lowered blood glucose levels; thus, Cγ showed promise as a new anti-diabetic compound for type 2 diabetes (T2D) treatment. The aim of this study was to evaluate the effect of Cγ on Ins-1 gene expression and on pancreatic insulin content in streptozotocin-mediated diabetic rats. Cγ was isolated from Lupinus albus seeds. Its identification was confirmed with polyacrylamide gel electrophoresis under native and denaturing conditions. We used streptozotocin (STZ) to induce T2D on the 5th day of life of newborn male Wistar rats (n5-STZ). After 20 weeks post-induction, these animals (glycemia > 200 mg/dL) were randomly assigned to three groups that received the following one-week treatments: vehicle, 0.90% w/v NaCl (n5 STZ-Ctrl); glibenclamide, 10 mg/kg (n5 STZ-Glib); or Cγ, 120 mg/kg (n5 STZ-Cγ). Glucose and insulin levels were measured before and after treatment. Ins-1 gene expression was quantified using real time polymerase chain reaction and the pancreatic insulin content was evaluated with immunohistochemistry. Post-treatment, the n5 STZ-Cγ and n5 STZ-Glib groups showed reductions in glucose, increments in serum insulin, and increases in Ins-1 gene expression and beta cell insulin content compared to the n5 STZ-Ctrl group. The results showed that Cγ had beneficial effects on Ins-1 gene expression and pancreatic insulin content. These biological effects of Cγ strengthen its promising potential as a nutraceutical and/or new agent for controlling hyperglycemia.

Proteomic analysis of Lupinus angustifolius (var. Zeus and Bojar) and Lupinus luteus (var. Lord and Parys) seed proteins and their hydrolysates

“…Until now, it has been confirmed that the health promoting properties of lupin seeds are a result of the presence of the protein fraction‐γ‐conglutin, which can be used effectively in the treatment of diabetes . Based on exposure of human hepatocyte cell line (HepG2) to γ‐conglutin, Lovati et al .…”

Functional Properties of Lupinus angustifolius Seed Protein Isolates

“…In addition, Lupinus are more adaptable to regions with low fertility soils and mild or very cold winters compared to soybean cultivation [10]. The seeds of these species represent a functional food ingredient because their proteins are related to the prevention of cardiovascular diseases, and it had been found that their proteins (conglutins) reduce blood glucose in hyperglycemic rats [11,12]. In this way, obtaining protein isolates of Lupinus by isoelectric precipitation is an alternative for the commercial production of food ingredients.…”

Suppressive effects of γ‐conglutin on differentiation of 3T3‐L1 preadipocytes

“…It was found that orally administrated c-conglutin reduces glucose levels in hyperglycemic rats (Magni et al, 2004;Lovati et al, 2012). Another study demonstrated that c-conglutin administration improves glucose control and enhances insulin 1 mRNA expression as well as pancreatic insulin content in diabetic rats (Vargas-Guerrero et al, 2014). A recent in vivo study suggested that c-conglutin reduces hepatic glucose production by downregulation of glucose-6-phosphatase expression in insulin resistant and type 2 diabetic rats (Gonzalez-Santiago et al, 2017).…”