ВЛИЯНИЕ С-ПЕПТИДА ПРОИНСУЛИНА И ИНСУЛИНА НА ГОНАДНУЮ И ТИРЕОИДНУЮ СИСТЕМЫ У САМЦОВ КРЫС С МЯГКОЙ ФОРМОЙ САХАРНОГО ДИАБЕТА 1-ГО ТИПА

Type 1 diabetes mellitus (T1DM) is characterized by a deficiency of insulin, as well as C-peptide, which is a modulator of the activity of insulin signaling pathways. The C-peptide replacement therapy for T1DM improves metabolic performance, restores the functions of the nervous and excretory systems. It is believed that through central mechanisms it can restore the functions of the endocrine system that are impaired in T1DM. To compensate the deficiency of the C-peptide in the CNS, an intranasal route of administration can be used. The aim was to study the effect of treatment (9 days) of male Wistar rats with a model of mild T1DM induced by a low-dose streptozotocin (35 mg/kg) using intranasally administered C-peptide (36 μg/rat/day) and insulin (20 μg/rat/day), jointly or separately, on the hormonal parameters of the thyroid and gonadal systems, as well as on the activity of adenylyl cyclase (AC) in the membranes isolated from the thyroid and testes. The enzyme adenylyl cyclase is involved in the regulation of the synthesis of thyroid hormones in the thyrocytes and testosterone in the Leydig cells. The plasma levels of thyroid-stimulating (TSH) and luteinizing hormones (LH), thyroid hormones, testosterone, insulin and leptin were measured. The treatment of rats with a C-peptide in the combination with insulin caused a decrease in hyperglycemia, despite hypoinsulinemia, restored the reduced levels of triiodothyronine, testosterone and leptin, normalized the TSH level increased in T1DM, and did not affect the LH level, which did not change in the conditions of T1DM. One of the mechanisms for normalizing the functions of the thyroid and gonadal systems in the case of treatment with the insulin and C-peptide was the restoration of the stimulating effect of TSH on AC activity in the thyroidal membranes and the corresponding effect of human chorionic gonadotropin in the testicular membranes. The monotherapy with insulin was less effective, while monotherapy with C-peptide partially restored an androgen status only on the third day after the start of treatment. Thus, we have shown the potentiating effect of the C-peptide on insulin-induced restoration of the functions of the thyroid and gonadal systems in rats with mild T1DM, which, in our opinion, is based on the enhancement of insulin signaling in the hypothalamus in the presence of the C-peptide.