Abstract

Luteinizing hormone (LH) and human chorionic gonadotropin (hCG), due to binding to the LH/hCG receptor, activate the adenylyl cyclase (AC) system which regulates testosterone (T) production. Long-term administration of LH and hCG causes desensitization of this system and attenuates the steroidogenic response, thereby necessitating the search for new agonists of the LH/hCG receptor. The aim of the work was to explore, in comparison with hCG, the stimulatory effects of the previously developed thieno[2,3-d]pyrimidines, TP03 and TP04, and a new thieno[2,3-d]pyrimidine derivative, 5-amino-N-(tert-butyl)-4-(3-(4-aminopyrimidine-5-carboxamido)-phenyl)-2-(methylthio)thieno[2,3-d]pyrimidine-6-carboxamide (TP37), on AC activity in rat testicular membranes, as well as on T production and gene expression of the LH/hCG receptor and the key testicular steroidogenic proteins under conditions of a single and 3-day administration to male rats. hCG increased AC activity in testicular membranes more efficiently compared to thieno[2,3-d]pyrimidines, and after a single injection (50 and 100 IU/rat) was superior to TP03 and TP04 (15–50 mg/kg) in its steroidogenic effect. After a 3-day administration, the steroidogenic effect of hCG was attenuated compared to that for TP03 and TP04. After 3 days of treatment with gonadotropin, testicular expression of genes encoding the StAR protein and cytochrome P450scc was considerably increased, but expression of the Lhr and Cyp17a1 genes encoding LH/hCG receptor and cytochrome P450-17α was suppressed. TP03 and TP04 slightly increased StAR gene expression but did not affect expression of other genes. TP37, which was active in vitro, after a short stimulation of T production, suppressed the steroidogenic function at a dose of 50 mg/kg, probably due to its degradation and the ability to suppress Cyp17a1 gene expression. Our data indicate significant differences in the mechanisms underlying the effect of gonadotropins and thieno[2,3-d]pyrimidines with an activity of LH/hCG receptor agonists on testicular steroidogenesis. We also demonstrate that long-term administration of thieno[2,3-d]pyrimidines to stimulate T production does not attenuate steroidogenesis and induces no LH resistance.

中文翻译：

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黄体化激素受体的正构和变构激动剂对睾丸类固醇生成的差异刺激

摘要

促黄体生成激素（LH）和人绒毛膜促性腺激素（hCG）由于与LH / hCG受体结合而激活了调节睾丸激素（T）产生的腺苷酸环化酶（AC）系统。长期服用LH和hCG会导致该系统脱敏并减弱类固醇生成反应，因此有必要寻找LH / hCG受体的新激动剂。与hCG相比，该研究的目的是探索以前开发的噻吩并[2,3- d ]嘧啶TP03和TP04以及新的噻吩并[2,3- d ]嘧啶衍生物5的刺激作用。-氨基-N-（叔-丁基）-4-（3-（4-氨基嘧啶-5-甲酰胺基）-苯基）-2-（甲硫基）噻吩并[2,3-d]嘧啶-6-甲酰胺（TP37）对大鼠睾丸AC活性的影响在雄性大鼠单次和3天给药的条件下，以及LH / hCG受体和关键睾丸类固醇生成蛋白的T膜和T产生和基因表达。与thieno [2,3-d]嘧啶相比，hCG可以更有效地提高睾丸膜的AC活性，单次注射（50和100 IU /大鼠）后，其CG活性优于TP03和TP04（15–50 mg / kg）类固醇生成作用。3天给药后，与TP03和TP04相比，hCG的类固醇生成作用减弱。促性腺激素治疗3天后，编码StAR蛋白和细胞色素P450scc的基因的睾丸表达显着增加，但编码LH / hCG受体和细胞色素P450-17α的Lhr和Cyp17a1基因被抑制。TP03和TP04稍微增加了StAR基因的表达，但不影响其他基因的表达。TP37在短暂刺激T产生后在体外具有活性，它以50 mg / kg的剂量抑制了类固醇生成功能，这可能是由于其降解和抑制Cyp17a1基因表达的能力所致。我们的数据表明促性腺激素和噻吩并[2,3- d ]嘧啶具有LH / hCG受体激动剂的活性对睾丸类固醇生成的作用机理上存在显着差异。我们还证明了thieno [2,3- d]嘧啶类药物刺激T产生并不会减弱类固醇生成，也不会引起LH抵抗。