Diosgenin biosynthesis pathway and its regulation in Dioscorea cirrhosa L.

Dioscorea cirrhosa L. (D. cirrhosa) tuber is a traditional medicinal plant that is abundant in various pharmacological substances. Although diosgenin is commonly found in many Dioscoreaceae plants, its presence in D. cirrhosa remained uncertain. To address this, HPLC-MS/MS analysis was conducted and 13 diosgenin metabolites were identified in D. cirrhosa tuber. Furthermore, we utilized transcriptome data to identify 21 key enzymes and 43 unigenes that are involved in diosgenin biosynthesis, leading to a proposed pathway for diosgenin biosynthesis in D. cirrhosa. A total of 3,365 unigenes belonging to 82 transcription factor (TF) families were annotated, including MYB, AP2/ERF, bZIP, bHLH, WRKY, NAC, C2H2, C3H, SNF2 and Aux/IAA. Correlation analysis revealed that 22 TFs are strongly associated with diosgenin biosynthesis genes (-r2- > 0.9, P < 0.05). Moreover, our analysis of the CYP450 gene family identified 206 CYP450 genes (CYP450s), with 40 being potential CYP450s. Gene phylogenetic analysis revealed that these CYP450s were associated with sterol C-22 hydroxylase, sterol-14-demethylase and amyrin oxidase in diosgenin biosynthesis. Our findings lay a foundation for future genetic engineering studies aimed at improving the biosynthesis of diosgenin compounds in plants.

Diabetes mellitus promotes susceptibility to periodontitis-novel insight into the molecular mechanisms.

Diabetes mellitus is a main risk factor for periodontitis, but until now, the underlying molecular mechanisms remain unclear. Diabetes can increase the pathogenicity of the periodontal microbiota and the inflammatory/host immune response of the periodontium. Hyperglycemia induces reactive oxygen species (ROS) production and enhances oxidative stress (OS), exacerbating periodontal tissue destruction. Furthermore, the alveolar bone resorption damage and the epigenetic changes in periodontal tissue induced by diabetes may also contribute to periodontitis. We will review the latest clinical data on the evidence of diabetes promoting the susceptibility of periodontitis from epidemiological, molecular mechanistic, and potential therapeutic targets and discuss the possible molecular mechanistic targets, focusing in particular on novel data on inflammatory/host immune response and OS. Understanding the intertwined pathogenesis of diabetes mellitus and periodontitis can explain the cross-interference between endocrine metabolic and inflammatory diseases better, provide a theoretical basis for new systemic holistic treatment, and promote interprofessional collaboration between endocrine physicians and dentists.

Therapeutic potential of toosendanin: Novel applications of an old ascaris repellent as a drug candidate.

Toosendanin (TSN), extracted from Melia. toosendan Sieb.et Zucc. and Melia. azedarach L., has been developed into an ascaris repellent in China. However, with the improvement of public health protection, the incidence of ascariasis has been reduced considerably, resulting in limited medical application of TSN. Therefore, it is questionable whether this old ascaris repellent can develop into a drug candidate. Modern studies have shown that TSN has strong pharmacological activities, including anti-tumor, anti-botulinum, anti-viral and anti-parasitic potentials. It also can regulate fat formation and improve inflammation. These researches indicate that TSN has great potential to be developed into a corresponding medical product. In order to better development and application of TSN, the availability, pharmacodynamics, pharmacokinetics and toxicology of TSN are summarized systematically. In addition, this review discusses shortcomings in the current researches and provides useful suggestions about how TSN developed into a drug candidate. Therefore, this paper illustrates the possibility of developing TSN as a medical product, aimed to provide directions for the clinical application and further research of TSN.

Novel wine in an old bottle: Preventive and therapeutic potentials of andrographolide in atherosclerotic cardiovascular diseases.

Atherosclerotic cardiovascular disease (ASCVD) frequently results in sudden death and poses a serious threat to public health worldwide. The drugs approved for the prevention and treatment of ASCVD are usually used in combination but are inefficient owing to their side effects and single therapeutic targets. Therefore, the use of natural products in developing drugs for the prevention and treatment of ASCVD has received great scholarly attention. Andrographolide (AG) is a diterpenoid lactone compound extracted from Andrographis paniculata. In addition to its use in conditions such as sore throat, AG can be used to prevent and treat ASCVD. It is different from drugs that are commonly used in the prevention and treatment of ASCVD and can not only treat obesity, diabetes, hyperlipidaemia and ASCVD but also inhibit the pathological process of atherosclerosis (AS) including lipid accumulation, inflammation, oxidative stress and cellular abnormalities by regulating various targets and pathways. However, the pharmacological mechanisms of AG underlying the prevention and treatment of ASCVD have not been corroborated, which may hinder its clinical development and application. Therefore, this review summarizes the physiological and pathological mechanisms underlying the development of ASCVD and the in vivo and in vitro pharmacological effects of AG on the relative risk factors of AS and ASCVD. The findings support the use of the old pharmacological compound ('old bottle') as a novel drug ('novel wine') for the prevention and treatment of ASCVD. Additionally, this review summarizes studies on the availability as well as pharmaceutical and pharmacokinetic properties of AG, aiming to provide more information regarding the clinical application and further research and development of AG.

Associations of blood metals with liver function: Analysis of NHANES from 2011 to 2018.

BACKGROUND: Heavy metals have been reported to affect liver function. However, there is currently little and inconsistent knowledge about the effects of combined and individual blood metals on specific parameters of liver function in the general population. Hence, this study aimed to elucidate their associations. METHODS: Data from National Health and Nutrition Examination Survey (NHANES) 2011-2018 were used in this cross-sectional study. Multivariate linear, and a quantile-based g-computation (qgcomp) were applied to explore the associations between blood metals [mercury (Hg), manganese (Mn), lead (Pb), cadmium (Cd), selenium (Se)], alone and in combination, and liver function parameters [alanine transaminase (ALT), aspartate transaminase (AST), ALT/AST, alkaline phosphatase (ALP), gamma-glutamyl transferase (GGT) and serum total bilirubin (TBIL)]. RESULTS: A total of 15,328 were included. Multivariate linear models indicated that liver function was significantly associated with blood heavy metals. The most significant relationship was found between Se and AST (ß 5.09, 95%CI (3.28,6.91), p＜0.001), Mn and ALT (ß 1.24, 95%CI (0.57, 1.91), p＜0.001). Furthermore, the qgcomp analysis showed that the combination of five blood metals was positively associated with AST, ALT, GGT, TBIL and HSI. Cd contributed the most to the correlation of AST (weight = 0.447), Se contributed the most to the association of ALT (weight = 0.438) and HSI (weight = 0.570), Pb contributed the most to the association of GGT (weight = 0.421) and Hg contributed the most to the correlation of TBIL (weight = 0.331). CONCLUSIONS: Blood heavy metal levels were significantly associated with liver function parameters. Further studies are required to clarify the relationship between heavy metals and liver function.

Andrographolide: A review of its pharmacology, pharmacokinetics, toxicity and clinical trials and pharmaceutical researches.

Andrographis paniculata (Burm. f.) Wall. ex Nees, a renowned herb medicine in China, is broadly utilized in traditional Chinese medicine (TCM) for the treatment of cold and fever, sore throat, sore tongue, snake bite with its excellent functions of clearing heat and toxin, cooling blood and detumescence from times immemorial. Modern pharmacological research corroborates that andrographolide, the major ingredient in this traditional herb, is the fundamental material basis for its efficacy. As the main component of Andrographis paniculata (Burm. f.) Wall. ex Nees, andrographolide reveals numerous therapeutic actions, such as antiinflammatory, antioxidant, anticancer, antimicrobial, antihyperglycemic and so on. However, there are scarcely systematic summaries on the specific mechanism of disease treatment and pharmacokinetics. Moreover, it is also found that it possesses easily ignored security issues in clinical application, such as nephrotoxicity and reproductive toxicity. Thereby it should be kept a lookout over in clinical. Besides, the relationship between the efficacy and security issues of andrographolide should be investigated and evaluated scientifically. In this review, special emphasis is given to andrographolide, a multifunctional natural terpenoids, including its pharmacology, pharmacokinetics, toxicity and pharmaceutical researches. A brief overview of its clinical trials is also presented. This review intends to systematically and comprehensively summarize the current researches of andrographolide, which is of great significance for the development of andrographolide clinical products. Noteworthy, those un-cracked issues such as specific pharmacological mechanisms, security issues, as well as the bottleneck in clinical transformation, which detailed exploration and excavation are still not to be ignored before achieving integration into clinical practice. In addition, given that current extensive clinical data do not have sufficient rigor and documented details, more high-quality investigations in this field are needed to validate the efficacy and/or safety of many herbal products.

Naringenin: A Promising Therapeutic Agent against Organ Fibrosis.

Fibrosis is the final common pathology of most chronic diseases as seen in the heart, liver, lung, kidney, and skin and contributes to nearly half of death in the developed countries. Fibrosis, or scarring, is mainly characterized by the transdifferentiation of fibroblasts into myofibroblasts and the excessive accumulation of extracellular matrix (ECM) secreted by myofibroblasts. Despite immense efforts made in the field of organ fibrosis over the past decades and considerable understanding of the occurrence and development of fibrosis gained, there is still lack of an effective treatment for fibrotic diseases. Therefore, identifying a new therapeutic strategy against organ fibrosis is an unmet clinical need. Naringenin, a flavonoid that occurs naturally in citrus fruits, has been found to confer a wide range of pharmacological effects including antioxidant, anti-inflammatory, and anticancer benefits and thus potentially exerting preventive and curative effects on numerous diseases. In addition, emerging evidence has revealed that naringenin can prevent the pathogenesis of fibrosis in vivo and in vitro via the regulation of various pathways that involved signaling molecules such as transforming growth factor-ß1/small mother against decapentaplegic protein 3 (TGF-ß1/Smad3), mitogen-activated protein kinase (MAPK), phosphatidylinositol 3-kinase/protein kinase B (PI3K/Akt), sirtuin1 (SIRT1), nuclear factor-kappa B (NF-κB), or reactive oxygen species (ROS). Targeting these profibrotic pathways by naringenin could potentially become a novel therapeutic approach for the management of fibrotic disorders. In this review, we present a comprehensive summary of the antifibrotic roles of naringenin in vivo and in vitro and their underlying mechanisms of action. As a food derived compound, naringenin may serve as a promising drug candidate for the treatment of fibrotic disorders.

Modulation of the 5-HT3A receptor current by desacylbaldrinal.

The serotonin (5-hydroxytryptamine) type 3 receptor is an important target in the control of digestive dysfunction such as anorexia and bulimia, and 5-HT3 receptor antagonists are effective against eating disorder and the early-phase chemotherapy and radiotherapy evoked vomiting. Our previous research of Valeriana jatamansi revealed the presence of iridoids, which showed potent antitumor activities. Here, we explored the effects of 10π aromatic iridoid desacylbaldrinal isolated from V. jatamansi on the 5-HT3 receptor current. We performed whole cell recordings of 5-HT3A receptor currents in the presence of the compound. The result indicated that desacylbaldrinal inhibited the 5-HT-mediated 5-HT3A receptor current.

Puerariae Lobatae radix flavonoids and puerarin alleviate alcoholic liver injury in zebrafish by regulating alcohol and lipid metabolism.

Exessive drinking is commonly associated with a wide spectrum of liver injuries. The term alcoholic liver disease (ALD) is generally used to refer to this spectrum of hepatic abnormalities, and the term hepatic steatosis denotes early lesions. Puerariae Lobatae Radix (PLR) is a common traditional Chinese medicine and has been widely used as an efficient treatment for alcohol-induced damage. Flavonoids are the principal components of PLR that could potentially be responsible for the activation of alcohol metabolism and lipid-lowering effects. However, little is known about the mechanisms underlying their activity against alcoholic injury. In this study, PLR flavonoids (PLF) were obtained by microwave extraction. A 2% ethanol solution was used to establish a model of alcoholic fatty liver disease by exposure of zebrafish larvae for 32 h, and then the zebrafish were administered PLF and puerarin. The results showed that PLF and puerarin significantly decreased lipid accumulation and the levels of total cholesterol and triglycerides in zebrafish larvae. Moreover, PLF and puerarin downregulated the expression of genes related to alcohol and lipid metabolism (CYP2y3, CYP3a65, ADH8a, ADH8b, HMGCRB, and FASN), endoplasmic reticulum stress, and DNA damage (CHOP, EDEM1, GADD45αa, and ATF6) and reduced levels of inflammatory factors (IL-1ß, TNF-α) in zebrafish larvae. PLF and puerarin increased the phosphorylation of AMP-activated protein kinase-α (AMPKα) and decreased the total protein level of ACC1. The findings suggested that PLF and puerarin alleviated alcohol-induced hepatic steatosis in zebrafish larvae by regulating alcohol and lipid metabolism, which was closely related to the regulation of the AMPKα-ACC signaling pathway. In conclusion, the study provided a possible therapeutic drug for ALD treatment.

A real-time fuzzy logic biofeedback controller for freestyle swimming body posture adjustment.

Wearable body area networks (BANs) have been widely used in activity measurements for kinematic information collection. This paper presents the design and implementation of a wearable device used as a training tool in freestyle swimming. The device supplies a close-loop control mechanism via a fuzzy logic controller. Swimming posture data is collected quantitatively and audibly fed back to swimmers in real time through bone conductors. Two recreational swimmers were invited to participate in a series of experiments including 7 days of baseline capability test (no feedback), 7 days of feedback training, and 2 days of retention test. It was found that both swimmers could well adapt to the feedback instructions. A maximum of 7.62% of lap time improvement and 29.64% of trunk roll improvement were observed in FB training, and such pattern was maintained after feedback was removed. We conclude that real-time fuzzy logic feedback can be used to improve recreational swimmers performance.

Combination of c oxidase subunit I based deoxyribonucleic acid barcoding and HPLC techniques for the identification and quality evaluation of Pheretima aspergillum.

This study aimed to identify Pheretima aspergillum (Guang-Pheretima) and its adulterants using the cytochrome c oxidase subunit I based deoxyribonucleic acid barcoding technology, and further to evaluate their quality using an optimized high-performance liquid chromatography method. For deoxyribonucleic acid barcoding identification, the Kimura-2-Parameter model was used to analyze genetic distance, and phylogenetic neighbor-joining tree was constructed for species identification of 20 labeled Guang-Pheretima samples. A high-performance liquid chromatography method was developed for the simultaneous determination of seven nucleoside components for quality evaluation. Compared with the GenBank database, 10 samples were identified as real Guang-Pheretima (P. aspergillum), and the others as the adulterants-Metaphire magna. The maximum intraspecific genetic distances of c oxidase subunit I sequence for P. aspergillum were smaller than the minimum interspecific genetic distances between P. aspergillum and M. magna. Ten P. aspergillum and 10 M. magna samples were clearly clustered in the neighbor-joining tree. The contents of seven nucleosides components in P. aspergillum were significantly higher than that in its adulterant-M. magna. The incidence of adulterants for Guang-Pheretima was high (up to 50%) with an alarming quality. This study provided a powerful idea for the quality evaluation of other highly valuable plant- or animal-derived products for safety concerns to avoid misidentification.

Neuroprotective Effects of Taraxacum officinale Wigg. Extract on Glutamate-Induced Oxidative Stress in HT22 Cells via HO-1/Nrf2 Pathways.

Oxidative stress-mediated neuron damage is considered an important contributor to the pathogenesis and development of neurodegenerative diseases. Taraxacum officinale has been reported to possess antioxidant activities. However, whether it can protect neurons against oxidative damage and the underlying molecular mechanisms have not been fully determined. In the present study, we examined the neuroprotective effects of ethanol extracts of this plant (ETOW) on glutamate-induced oxidative stress in HT22 cells. Both cell viability and reactive oxygen species (ROS) assays showed that ETOW effectively attenuated glutamate-induced cytotoxicity and ROS generation. Furthermore, our results revealed that ETOW increased the expression of heme oxygenase-1 (HO-1) and promoted the nuclear translocation of nuclear factor erythroid 2-related factor-2 (Nrf2). The inhibitory effects of ETOW on glutamate-stimulated cell toxicity and ROS production were partially reversed by tin protoporphyrin (SnPP), an HO activity inhibitor. Taken together, these results demonstrate that ETOW can protect HT22 cells against glutamate-induced oxidative damage by inducing the Nrf2/HO-1 pathways. Our study supports the idea that Taraxacum officinale Wigg. is a promising agent for preventing neurodegenerative diseases.

[Brain Protection of Muscone in Rats with Brain Injury].

OBJECTIVE: To observe cerebral protective effect of muscone (nasal administration) on traumatic brain injury model rats. METHODS: SD rats were divided into the sham-operation group, the model group, and the treatment groups according to random digit table, 50 in each group. Traumatic brain injury model was established by controlled cortical strike. Rats in the sham-operation group received surgery and anesthesia procedures only, with no strike. Muscone (1.8 mg/kg) was delivered to rats in the treatment group using in situ nasal perfusion, 30 min each time, twice daily for 7 successive days. Water content of brain tissue was detected in each group before intervention (T1), at day 3 of intervention (T2), day 5 of intervention (T3), and after intervention (T4), respectively. Expression levels of brain derived neurotrophic factor (BDNF) and nerve growth factor (NGF) were detected using immunohistochemical analysis. RESULTS: Compared with the sham-operated group, water content of brain tissue increased (P < 0.05), and expression levels of NGF and BDNF decreased in the model group at T1, T2, T3, and T4 (P <0. 01). Compared with the model group, water content of brain tissue decreased (P < 0.05), and expression levels of NGF and BDNF increased (P < 0.01) in the treatment group at T1, T2, and T3. CONCLUSION: Nasal administration of muscone could reduce water content of brain tissue, alleviate cerebral edema, promote secretion of BDNF and NGF by olfactory ensheathing cells in traumatic brain injury rats.

[Protective effect of ginsenoside Rg1 again PC-12 cells in OGD injury through mTOR/Akt/FoxO3 signaling pathway].

OBJECTIVE: To investigate the protective effect of ginsenoside Rg1 on oxygen-glucose deprivation (OGD) in PC-12 cells, and preliminarily discuss the potential molecular mechanism of mTOR/Akt/FoxO3 signaling pathway. METHOD: The OGD PC-12 cell model was established. The cell viability was measured by MTT assay. After the pretreatment with Rg1 with the concentration of 10, 20, 40 micromol x L(-1) for 24 h, the cell viability was observed. Lactate dehydrogenase (LDH) release, superoxide dismutase (SOD) ac- tivity and malondialdehyde (MDA) level were detected by colorimetry assay. mTOR, p-Akt(ser473), p-Akt(tjr308), Akt, p-FoxO3, FoxO3 in cytoplasm and nucleus, and total FoxO3 protein expression were detected by Western blot assay. RESULT: OGD could significantly in- hibit cell proliferation in 4-24 h in a time-dependent manner. After pretreatment for 24 h, Rg1 (20, 40 micromol x L(-1)) could notably elevate the cell viability and SOD viability and reduce the LDH release and MDA content. Besides, Rg1 also inhibited OGD-induced mTOR and p-Akt(ser473) decreases. After treatment for 6 h, OGD could reduce FoxO3 phosphorylation and promote FoxO3 in cytoplasm. This data suggested that Rg1 could protect PC-12 cell injury through mTOR/p-Akt/FoxO3 signaling pathway. CONCLUSION: Ginsenoside Rg1 could attenuate OGD-induced PC-12 cell injury. Its action mechanism may be closely related to activation of mTOR/p-Akt/FoxO3 signaling pathway.

In vivo inhibitory effects of puerarin on selected rat cytochrome P450 isoenzymes.

Puerarin, the major bioactive constituent in kudzu root, is used widely in China for the treatment of cardiovascular diseases and diabetes. The purpose of this study was to find out whether puerarin influences the effect on rat cytochrome P450 (CYP) enzymes (CYP2B6, CYP2C9 and CYP3A4) by using cocktail probe drugs in vivo. A cocktail solution at a dose of 5 mL/kg, which contained bupropion (20 mg/kg), tolbutamide (5 mg/kg) and midazolam (20 mg/kg), was given as oral administration to rats treated with 10 days oral administration of puerarin. Blood samples were collected at a series of time-points and the concentrations of probe drugs in plasma were determined by HPLC-MS/MS. The results showed that treatment with multiple doses of puerarin had inhibitory effects on rat CYP2B6, CYP2C9 and CYP3A4 enzyme activities. Therefore, caution is needed when puerarin is co-administered with CYP substrates, in view of herb-drug interactions.

Kidney-tonifying recipe can repair alterations in adrenal medullary chromaffin cells in asthmatic rats.

Traditional Chinese medicine suggests that renal deficiency is a causative factor of asthma, and tonifying kidney drugs are believed to be an appropriate and beneficial treatment. The adrenal medullary chromaffin cells (AMCC) transition to the neuronal phenotype is known to occur in asthma, as evidenced by degranulation of chromaffin granules, decline of epinephrine (EPI) and phenylethanolamine-n-methyl transferase (PNMT), and obvious alterations in cellular architecture. In this study, rats were sensitized and challenged with ovalbumin, then treated with Kidney-Tonifying Recipe (KTR) to evaluate the therapeutic effect. Tissues were evaluated for changes in pathology and EPI, PNMT, and peripherin expression. Degranulation of chromaffin granules and appearance of neurite-like process were found in AMCC from asthmatic rats, and these changes were corrected by KTR treatment. EPI and PNMT expressions were decreased in asthmatic rats and increased by KTR treatment. Peripherin expression was increased in asthmatic rats and decreased in the KTR-treated group. Morphological changes and decreases in EPI were observed when cultured AMCC were exposed to sera from asthmatic rats in vitro, and these changes were attenuated with the addition of sera from KRT-treated rats. These results suggest that the Kidney-Tonifying Recipe is capable of repairing asthma-associated alterations in endocrine function and the ultrastructure of AMCC.

[Effects of jianwei yuyang granule on inflammatory reaction and NF-kappaB expression in rat gastric mucosa of ulcer healing and recurrence].

OBJECTIVE: To observe the effects of Jianwei Yuyang granule (JWYY) on inflammatory reaction and NF-kappaB expression in rat gastric mucosa of ulcer healing and recurrence. METHOD: Gastric ulcer was induced in rat by acetic acid according Okeba's method with some modification and the recurrence model was induced by IL-1beta. Pathohistology of ulcer healing and recurrence was observed. Density of inflammatory cell infiltrating regenerative mucosa, NF-kappaB protein and mRNA expression were measured. RESULT: JWYY had effects on improving the quality of ulcer healing, reducing the rate of ulcer recurrence, decreasing the density of inflammatory cell infiltrating regenerative mucosa and suppressing the activation and expression quantity of NF-kappaB protein and mRNA. CONCLUSION: JWYY may promote the ulcer healing and prevent the recurrence of the gastric ulcer by suppressing the activation of NF-kappaB and the following inflammatory reaction.

Effects of jianwei yuyang granule on inflammatory reaction and NF-kappaB expression in rat gastric mucosa of ulcer healing and recurrence / 中国中药杂志

<p><b>OBJECTIVE</b>To observe the effects of Jianwei Yuyang granule (JWYY) on inflammatory reaction and NF-kappaB expression in rat gastric mucosa of ulcer healing and recurrence.</p><p><b>METHOD</b>Gastric ulcer was induced in rat by acetic acid according Okeba's method with some modification and the recurrence model was induced by IL-1beta. Pathohistology of ulcer healing and recurrence was observed. Density of inflammatory cell infiltrating regenerative mucosa, NF-kappaB protein and mRNA expression were measured.</p><p><b>RESULT</b>JWYY had effects on improving the quality of ulcer healing, reducing the rate of ulcer recurrence, decreasing the density of inflammatory cell infiltrating regenerative mucosa and suppressing the activation and expression quantity of NF-kappaB protein and mRNA.</p><p><b>CONCLUSION</b>JWYY may promote the ulcer healing and prevent the recurrence of the gastric ulcer by suppressing the activation of NF-kappaB and the following inflammatory reaction.</p>

Biological characterization of a novel, orally active small molecule gonadotropin-releasing hormone (GnRH) antagonist using castrated and intact rats.

Gonadotropin-releasing hormone (GnRH) receptor antagonists have potential in treating numerous hormone-dependent pathologies including cancers of the prostate, breast, and ovary, endometriosis, and fertility disorders. An unmet clinical need exists for an orally available GnRH receptor antagonist. Guided by structure-activity relationships, ligand-based targeted library designs, and biomarker measurements, our discovery efforts have yielded a novel, small molecule GnRH receptor antagonist, 5-[(3,5,5,8,8-pentamethyl-5,6,7,8-tetrahydro-2-naphthalenyl)methyl]-N-(2,4,6-trimethoxyphenyl)-2-furamide (CMPD1). CMPD1 bound with low nanomolar affinities to human, rat, and mouse GnRH receptors (6.0, 3.8, and 2.2 nM, respectively). CMPD1 was more than 100-fold selective for GnRH receptors versus various G-protein-coupled receptors and other enzymes and ion channels. In cells expressing recombinant rat GnRH receptors, CMPD1 was a competitive antagonist of GnRH-stimulated increases in extracellular acidification rates in Cytosensor microphysiometer assays. In cells expressing recombinant human GnRH receptors, CMPD1 was a potent inhibitor of GnRH-stimulated total inositol phosphate accumulation. The effects of CMPD1 on circulating levels of luteinizing hormone (LH) and testosterone were studied in castrated and intact male rats, respectively. Intravenous and oral administration of CMPD1 dose dependently suppressed GnRH-mediated elevations of LH in castrated male rats and testosterone in gonad-intact male rats. Moreover, CMPD1, when given at 20 mg/kg i.v. to intact male rats, inhibited the elevations of LH and testosterone stimulated by the superagonist of GnRH, [d-Ala(6), des-Gly(10)]GnRH (GnRH-A). These data suggest that CMPD1 is a potent, selective, orally active GnRH receptor antagonist that may have potential application as a therapeutic agent for treating hormone-dependent cancers and diseases.