Application of an Allosteric Agonist of the Luteinizing Hormone Receptor for Reducing the Effective Dose of Gonadotropin in the Treatment of Androgen Deficiency in Rats with Type 1 Diabetes

In type 1 diabetes mellitus, the impaired testosterone synthesis in the testes leads to androgen deficiency. The long-term application of high gonadotropin doses for its correction decreases the sensitivity of luteinizing hormone/human chorionic gonadotropin (LH/hCG) receptors in Leydig cells to the endogenous gonadotropins. The aim of this work was to study the effect of a 3-day treatment of male Wistar rats with streptozotocin type 1 diabetes with the 5-amino-N-tert-butyl-2-(methylsulfanyl)-4-(3-(nicotinamido) phenyl)thieno[2,3-d]pyrimidine-6-carboxamide allosteric LH/hCG receptor agonist (TP03, 15 mg/kg/day) on steroidogenic effects of a relatively low-dose hCG (10 IU/rat, single dose, s.c.). Pretreatment of diabetic rats with TP03 enhanced the stimulatory effect of hCG on testosterone levels, slightly modifying its effects on the expression of steroidogenic proteins (Star, Cyp11a1, Cyp17a1) and LH/hCG receptor (Lhr) genes. Thus, in type 1 diabetes, TP03 increases the steroidogenic effect of low-dose hCG, at the same time as maintaining its effect on the gene expression of LH/hCG receptor and steroidogenesis enzymes in the testes.