Assessment of changes in carbohydrate metabolism parameters in rats with experimental diabetes mellitus of different origins under L-arginine and N-acetyl-L-cysteine administration

The aim: to determine the specificity of changes in carbohydrate metabolism in rats with experimental type 1 (DM1) and type 2 (DM2) diabetes mellitus and to analyze correlations of their modification under administration of the amino acids L-arginine and N-acetyl-L-cysteine. Materials and methods. DM1 was induced in old male Wistar rats by a single 45 mg/kg streptozotocin. In rats with DM2, insulin resistance was first induced (high-fat mixed feed for 8 weeks), after which 30 mg/kg streptozotocin was administered once. After 6 weeks, animals with DM were divided into 3 subgroups: without amino acid administration, rats with L-arginine and with N-acetyl-L-cysteine. Results. Experimental modeling of DM1 resulted in persistent hyperglycemia and hypoinsulinemia, which significantly altered metabolic indices. In rats with DM2, hyperglycemia developed with hyperinsulinemia, indicating established insulin resistance. Administration of L-arginine and N-acetyl-L-cysteine to rats with both types of diabetes lowered glucose levels and increased insulin concentrations, although no statistically significant difference was found between the effects of these amino acids. L-arginine significantly increased the HOMA-β index in rats with DM1 and moderately increased it in rats with DM2. In addition, it caused a significant increase in the HOMA-IR index in the group with DM1, indicating improved insulin sensitivity. N-acetyl-L-cysteine also improved HOMA-β and HOMA-IR indices in rats with DM1, although its effect on DM2 was less pronounced and did not reach statistical significance. Conclusions. In rats with type 1 diabetes, both amino acids cause a decrease in glucose concentration, which is due to improved pancreatic β-cell function due to increased insulin concentration, the HOMA-β index compared to the subgroup without correction, but also causes an increase in the HOMA-IR index, and the listed indicators do not return to control values. These changes were accompanied by profound disruption of metabolic relationships, which is confirmed by correlation analysis. Against the background of the development of type 2 diabetes mellitus, both amino acids reduce glucose concentration and increase insulin compared to the subgroup without correction, however, the HOMA-β index improves only in rats with L-arginine, and the preserved hyperinsulinemia in all 3 subgroups leads to an increase, compared to the control, in the HOMA-IR index without a significant difference between the effects of amino acids. Correlation analysis revealed greater preservation of metabolic relationships of carbohydrate metabolism indicators compared to rats with type 1 diabetes mellitus.