THE STIMULATING EFFECT OF THIENOPYRIMIDINES, THE STRUCTURAL ANALOGS OF ORG 43553, ON THE ACTIVITY OF ADENYLYL CYCLASE IN THE TESTES AND ON THE TESTOSTERONE PRODUCTION IN MALE RATS

The regulation of the functional activity of luteinizing hormone (LH) receptor can be carried out by using gonadotropins or low-molecular weight agonists of this receptor, which, unlike gonadotropins, bind to an allosteric site located in the transmembrane channel of the receptor. Thienopyrimidine derivatives, the analogs of the compound Org 43553, the greatest interest among the low-molecular weight agonists. The aim of the work was synthesis of the novel thienopyrimidine derivatives, such as 5-amino-N-(tert-butyl)-4-(3-(2-methoxynicotinamido) phenyl)-2-(methylthio)thieno [2,3-d]pyrimidine-6-carboxamide (TP-21), 4-(3-(5-amino-6-(tert-butylcarbamoyl)- 2-) methylthio)thieno[2,3-d] pyrimidine-4-yl)phenyl)carbamoyl)pyridine 1-ocide (TP-22) and 5-amino-N-(tert-butyl)-4-(3-(2-chloronicotinamido)-2-(methylthio)thieno[2,3-d] pyrimidine-6-carboxamide (TP-23), and the study of their effects in vitro on adenylyl cyclase (AC) activity in testicular membranes of rats as well in vivo on the testosterone level in the case of their intratesticular and intraperitoneally administration into male rats. The compounds TP-21, TP-22 and TP-23 stimulated the basal AS activity in rat testicular membranes with the EC50 values, such as 1556, 358 and 372 nM, and ranked according to their efficiency in the following order: TP-23 > TP-21 TP-22. In the case of combined action of thienopyrimidines (10­4 M) and human chorionic gonadotropin (hCG, 10­8 M), the AC stimulating effect of gonadotropin was preserved, but at a concentration of 10­4 M, the additivity of AC effects of thienopyrimidines and hCG was observed. The TP-21, TP-22 and TP-23, when i. t. administered into male rats at a dose of 10 mg/kg, increased the testosterone levels, and, 5 h after treatment, the increase of concentration of testosterone over its value in the control group was 32.8, 36.4 and 76.9 nM respectively. When administered intraparenterally, TP-21 and TP-22 had a little effect on the testosterone level, while the compound TP-23 showed significant increase in the testosterone level at 1 and 3 h (the increase over control amounted 34.8 and 18.9 nM). The data obtained indicate a high activity of TP-23, as a stimulator of the synthesis and secretion of testosterone, as well as the prospect of development on its basis of highly effective agonists of LH receptor.