In men with type 2 diabetes mellitus (T2DM), steroidogenesis and spermatogenesis are impaired. Metformin and the agonists of luteinizing hormone/human chorionic gonadotropin(hCG)-receptor (LH/hCG-R) (hCG, low-molecular-weight allosteric LH/hCG-R-agonists) can be used to restore them. The aim was to study effectiveness of separate and combined administration of metformin, hCG and 5-amino-N-tert-butyl-2-(methylsulfanyl)-4-(3-(nicotinamido)phenyl)thieno[2,3-d]pyrimidine-6-carboxamide (TP3) on steroidogenesis and spermatogenesis in male rats with T2DM. hCG (15 IU/rat/day) and TP3 (15 mg/kg/day) were injected in the last five days of five-week metformin treatment (120 mg/kg/day). Metformin improved testicular steroidogenesis and spermatogenesis and restored LH/hCG-R-expression. Compared to control, in T2DM, hCG stimulated steroidogenesis and StAR-gene expression less effectively and, after five-day administration, reduced LH/hCG-R-expression, while TP3 effects changed weaker. In co-administration of metformin and LH/hCG-R-agonists, on the first day, stimulating effects of LH/hCG-R-agonists on testosterone levels and hCG-stimulated expression of StAR- and CYP17A1-genes were increased, but on the 3–5th day, they disappeared. This was due to reduced LH/hCG-R-gene expression and increased aromatase-catalyzed estradiol production. With co-administration, LH/hCG-R-agonists did not contribute to improving spermatogenesis, induced by metformin. Thus, in T2DM, metformin and LH/hCG-R-agonists restore steroidogenesis and spermatogenesis, with metformin being more effective in restoring spermatogenesis, and their co-administration improves LH/hCG-R-agonist-stimulating testicular steroidogenesis in acute but not chronic administration.

Low-molecular-weight agonists of luteinizing hormone (LH)/human chorionic gonadotropin (hCG) receptor (LHCGR), which interact with LHCGR transmembrane allosteric site and, in comparison with gonadotropins, more selectively activate intracellular effectors, are currently being developed. Meanwhile, their effects on testicular steroidogenesis have not been studied. The purpose of this work is to perform a comparative study of the effects of 5-amino-N-tert-butyl-4-(3-(1-methylpyrazole-4-carboxamido)phenyl)-2-(methylthio)thieno[2,3-d] pyrimidine-6-carboxamide (TP4/2), a LHCGR allosteric agonist developed by us, and hCG on adenylyl cyclase activity in rat testicular membranes, testosterone levels, testicular steroidogenesis and spermatogenesis in young (four-month-old), aging (18-month-old) and diabetic male Wistar rats. Type 1 diabetes was caused by a single streptozotocin (50 mg/kg) injection. TP4/2 (20 mg/kg/day) and hCG (20 IU/rat/day) were administered for 5 days. TP4/2 was less effective in adenylyl cyclase stimulation and ability to activate steroidogenesis when administered once into rats. On the 3rd–5th day, TP4/2 and hCG steroidogenic effects in young adult, aging and diabetic rats were comparable. Unlike hCG, TP4/2 did not inhibit LHCGR gene expression and did not hyperstimulate the testicular steroidogenesis system, moderately increasing steroidogenic proteins gene expression and testosterone production. In aging and diabetic testes, TP4/2 improved spermatogenesis. Thus, during five-day administration, TP4/2 steadily stimulates testicular steroidogenesis, and can be used to prevent androgen deficiency in aging and diabetes.

Gonadotropins, including human chorionic gonadotropin (hCG), are used to induce ovulation, but they have a number of side effects, including ovarian hyperstimulation syndrome (OHSS). A possible alternative is allosteric luteinizing hormone (LH)/hCG receptor agonists, including the compound TP4/2 we developed, which remains active when administered orally. The aim was to study the effectiveness of TP4/2 (orally, 40 mg/kg) as an ovulation inducer in FSH-stimulated immature female rats, compared with hCG (s.c., 15 IU/rat). TP4/2 stimulated progesterone production and corpus luteum formation; time-dependently increased the ovarian expression of steroidogenic genes (Star, Cyp11a1, Cyp17a1) and genes involved in ovulation regulation (Adamts-1, Cox-2, Egr-1, Mt-1); and increased the content of metalloproteinase ADAMTS-1 in the ovaries. These effects were similar to those of hCG, although in some cases they were less pronounced. TP4/2, in contrast to hCG, maintained normal LH levels and increased the ovarian expression of the LH/hCG receptor gene, indicating preservation of ovarian sensitivity to LH, and did not cause a sustained increase in expression of vascular endothelial growth factor-A involved in OHSS. Thus, TP4/2 is an effective ovulation inducer that, unlike hCG, has a lower risk of OHSS and ovarian LH resistance due to its moderate stimulating effect on steroidogenesis.

The approaches to correct thyroid deficiency include replacement therapy with thyroid hormones (THs), but such therapy causes a number of side effects. A possible alternative is thyroid-stimulating hormone (TSH) receptor activators, including allosteric agonists. The aim of this work was to study the effect of ethyl-2-(4-(4-(5-amino-6-(tert-butylcarbamoyl)-2-(methylthio)thieno[2,3-d]pyrimidin-4-yl)phenyl)-1H-1,2,3-triazol-1-yl) acetate (TPY3m), a TSH receptor allosteric agonist developed by us, on basal and thyroliberin (TRH)-stimulated TH levels and the hypothalamic-pituitary-thyroid (HPT) axis in male rats with high-fat diet/low-dose streptozotocin-induced type 2 diabetes mellitus (T2DM). Single and three-day administration of TPY3m (i.p., 20 mg/kg) was studied, and the effect of TPY3m on the HPT axis was compared with that of levothyroxine. TPY3m increased TH levels when administered to both healthy and diabetic rats, normalizing thyroxine and triiodothyronine levels in T2DM and, unlike levothyroxine, without negatively affecting TSH levels or the expression of hypothalamic and pituitary genes responsible for TSH production. TPY3m pretreatment preserved the stimulatory effects of TRH on TH levels and thyroid gene expression. This indicates the absence of competition between TPY3m and endogenous TSH for TSH receptor activation and is supported by our in vitro results on TPY3m- and TSH-stimulated adenylate cyclase activity in rat thyroid membranes. Morphological analysis of thyroid glands in diabetic rats after three-day TPY3m administration shows an increase in its functional activity without destructive changes. To summarize, TPY3m, with the activity of a partial allosteric agonist of the TSH receptor, was created as a prototype of drugs to correct thyroid insufficiency in T2DM.

BACKGROUND: Gonadotropin preparations, particularly human chorionic gonadotropin (hCG), are commonly used to induce ovulation and treat reproductive disorders in women, albeit with associated side effects. Low-molecular-weight allosteric agonists of the luteinizing hormone receptor (LHR), such as thieno[2,3-d]pyrimidine derivatives, offer a potential alternative. AIM: This study aims to compare the effects of thieno[2,3-d]pyrimidine TP03 and hCG on ovarian weight, corpus luteum formation, and plasma levels of estradiol, progesterone, and luteinizing hormone in immature female rats pre-treated with Follimag®. It also examines their impact on ovarian gene expression related to LHR and steroidogenesis. MATERIALS AND METHODS: TP03 and hCG were administered 48 h after the Follimag® injection at a dose of 20 mg/kg (i.p.) and 15 IU/rat (s.c.), respectively. Parameters were assessed at 1, 2, 4, 8, 16, and 24 h after TP03 and hCG administration. Plasma hormone levels were measured via ELISA, and ovarian gene expression was analyzed using real-time PCR. RESULTS: TP03 increased ovarian weight, progesterone levels in the blood, and expression of steroidogenic genes encoding the cholesterol-transporting protein StAR and the cytochromes CYP11A1 and CYP17A1. TP03 also stimulated corpus luteum formation (16–24 h after treatment). The temporal dynamics of its stimulating effects were similar to those of hCG, although their magnitude was slightly inferior to those of gonadotropin. TP03-induced decrease in blood estradiol levels and aromatase gene expression in the ovaries was also more moderate. Unlike hCG, which suppressed LHR gene expression 8 h after treatment, TP03 maintained a high LHR gene expression, preserving ovarian sensitivity to endogenous luteinizing hormone. CONCLUSIONS: TP03 exhibits potential as an ovulation inducer with milder stimulating effects on ovarian steroidogenesis than hCG, which reduces the risks of developing ovarian hyperstimulation syndrome and resistance to gonadotropins.

BACKGROUND: In men, obesity is accompanied by a complex of metabolic and hormonal disorders, which leads to androgen deficiency and impaired spermatogenesis. Antidiabetic drugs, including metformin (MF), and luteinizing hormone receptor (LHR) agonists, which activate testicular steroidogenesis, can be used to correct reproductive dysfunctions. However, in diet-induced obesity (DIO), their effectiveness and mechanisms of action are poorly understood.AIM: In men, obesity is accompanied by a complex of metabolic and hormonal disorders, which leads to androgen deficiency and impaired spermatogenesis. Antidiabetic drugs, including metformin (MF), and luteinizing hormone receptor (LHR) agonists, which activate testicular steroidogenesis, can be used to correct reproductive dysfunctions. However, in dietinduced obesity (DIO), their effectiveness and mechanisms of action are poorly understood.MATERIALS AND METHODS: Obesity in male Wistar rats was induced by a 23-week diet enriched with saturated fats. MF treatment was carried out for 5 weeks at a dose of 120 mg/kg/day (orally), and the treatment with hCG and TP03 was carried out for 5 days at daily doses of 20 IU/rat (s.c.) and 15 mg/kg (i.p.), respectively. Using microscopy and histochemical analysis, the number and motility of spermatozoa (SP), the number of their defective forms and the morphology of the seminiferous tubules were assessed, and the levels of testosterone and other hormones in the blood were measured using ELISA.RESULTS: MF, hCG, and TP03 to varying degrees increased the number of SP and the proportion of their mobile forms, including those with forward movement, which were reduced in DIO rats, and also normalized the thickness of the epithelium of the seminiferous tubules and the number of spermatogonia and pachytene spermatocytes in them, but did not reduced the proportion of defective forms of SP, increased in DIO. In the case of MF, this was associated with the drug-induced normalization of body weight, glucose tolerance, and the insulin and leptin levels in DIO rats. The positive effect of hCG and TP03 on spermatogenesis was due to their stimulating effect on testosterone production.CONCLUSION: The use of long-term MF therapy and short-term courses of LHR-agonists normalizes impaired spermatogenesis in DIO, which indicates the prospects for their use to improve male fertility in obesity, and in the case of MF therapy, normalization of the metabolic and hormonal status is of great importance, while in the case of LHR-agonists the most important factor is their steroidogenic effect.