• Analytical Science and Technology
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• v.28 no.4
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• pp.278-287
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• 2015

Phosphodiesterase type 5 inhibitors (PDE-5 inhibitors) are used in the treatment of erectile dysfunction. In recent years, a number of reports have been conducted on dietary supplements contaminated with PDE-5 analogues. In this study, 58 analogues of PDE-5 inhibitors were sorted into five groups: tadalafil, sildenafil, hongdenafil, vardenafil, and other analogues. These analogues were then evaluated using a liquid chromatography-quadrupole-time of flight mass spectrometry (LC-QTOF-MS) electrospray ionization mass method. Each compound has a unique fragmentation ion, which can be easily analyzed qualitatively. The fragmentation pathways of the analogues were elucidated based on the QTOF-MS and MS/MS data. Common ions were confirmed for each group by analyzing the structural characteristics and fragmentation pathways. Specifically, common ions were observed at m/z 169.08 and 135.04 (tadalafil analogues), m/z 311.15 and 283.12 (sildenafil analogues and hongdenafil analogues), and m/z 312.16 and 151.09 (vardenafil analogues). The advantage of this method is that the structure of unknown components can be determined by interpreting the product ions. Hence, the developed method can be used for the identification of unknown compounds. Fragmentation pathways may also aid in the detection and identification of PDE-5 inhibitor analogues.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.1
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• pp.49-54
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• 1998

$Mg^{2+}$ is an important regulator of many cardiac functions. However, regulation of intracellular $Mg^{2+}$ activity in the heart is not well characterized. To assess the effect of histamine $H_2$-receptor stimulation on intracellular $Mg^{2+}$ regulation, changes in extracellular $Mg^{2+}$ concentration were examined under a variety of conditions in perfused guinea pig hearts. $Mg^{2+}$ in the cardiac perfusate was measured by atomic absorbance spectrophotometry. The histamine ($10^{-6}$ M) inuced a marked $Mg^{2+}$ efflux from the heart. The $H_2$-receptor antagonists, cimetidine ($10^{-6}$ M), ranitidined ($10^{-5}$ M), but not a H1-receptor antagonist, diphenhydramine ($3{\times}10^{-6}$ M), completely blocked the histamine-induced $Mg^{2+}$ efflux. The $Mg^{2+}$ efflux could also be induced by forskolin ($3{\times}10^{-6}$ M), 8-Cl-cAMP ($2{\times}10^{-4}$ M), permeable cAMP analogue, or dimaprit, ($10^{-5}$ M). However, the carbachol ($10^{-5}$ M) considerably decreased the efflux of $Mg^{2+}$. In the presence of papaverine ($10^{-5}$ M), a phosphodiesterase inhibitor, dimaprit-induced $Mg^{2+}$ efflux was potentiated. These results suggest that a significant $Mg^{2+}$ efflux from perfused guinea pig heart by histamine can be induced by the histamine $H_2$-receptor stimulation and it is suggested that cytosolic cAMP may be linked.

• The Korean Journal of Zoology
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• v.33 no.2
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• pp.175-182
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• 1990

Progesterone production and oocyte maturation in ovarian follicles of Rana nigromaculata and Rana rugosa were investigated. Addition of frog pituitary homogenate (FPH) to the in utiro cultured follicles of R. nigromaculata stimulated a marked increase in the accumulation and secretion of progesterone (P$_4$) by the follicles and induced their oocyte maturation (germinal vesicle breakdown, GVBD) in a dose dependent manner. The FPH (0.1 pituitary equivalent/2 ml)-inducted P4 peak appeared in 3-6 hours and followed by the oocyte GVBD in 9-12 hours after the hormone stimulation. lncreae of intrafollicular cAMP levels with forskolin (an adenylatecyclase stimulator) and 3-isobutyl-1-methylxanthine (IBMX, a phosphodiesterase inhibitor) mimic the FPH action in the stimulation of P$_4$ production but not in the induction of oocyte maturation. The in uitro cultured follicies of R. rugosa behaved very differently from other amphibian follicles. Addition of FPH-(0. 1 pit. equivl2 ml) to the culture medium neither stimulated P$_4$ production by the follicles nor induced the oocyte GVBD. However, treatment of the follicles with forskolin and IBMX drastically stimulated both the intrafollicular accumulation (800 pg/follicle) and secretion (1700 pg/follicle) of P$_4$ by the follicles during culture period. Thus, the data suggest that the follicles are ready to respond to cAMP increase but not to the FPH stimulation in terms of P$_4$ production.

• Journal of Chest Surgery
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• v.33 no.2
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• pp.117-124
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• 2000

Background: Nucleoside transport inhibitor(NTI) Keeps AMP, ADP, ATP levels high in myocytes by inhibiting adenosine cataboilsm so that it may preserve the myocardial contractability during ischemia In this study we investigated the effects of cyclic AMP phosphodiesterase inhibor(C-AMP PDSI) and S-P-nitrobenzyl-6 -thioniosine(NBT; a sort of NIT) on myocadial preservation and changes of constituent enzyme. Material and method: Twenty-six isolated rabbit hearts were perfused with Krebs-Henseleit buffer solution for 20 minutes arrested for 20 minutes and ten reperfused for 30 minutes. The following four groups were prepared and hemodynamic changes coronary effluent lactate dehydrogenase (LDH) a-hydroxybutylic accid(a-HBD) levels and myocardial LDH creatine kinase-MB (CK-MB) adenosine deaminase(ADA) a-HBD levels and myocardial LDH creatine kinase-MB (CK-MB) adenosine deaminase(ADA) a-HBD levels were analysed before and after cardiac arest ; Group I(control) ; the heart was only perfused with K-H ; Group II ; the heart was perfused with K-H including C-AMP PDSI(Amrinone 25mg/L); Group III ; the heart was perfused with K-H including NBT(4.19mg/L) ; Group IV ; the heart was perfused with K-H including C-AMP PDSI + NBT. Result : Left venticular developed pressure(LVDP) at 10 minutes of the equilibrium was significantly higher in group III(72.1$\pm$5.3 mmHg p<0.01) and group III(72$\pm$5.6 mmHg P<0.025) as compared with group I (40.8$\pm$4.7mmHg) and LVDP at 20 minutes of the reperfusion was significantly higher in group II(74$\pm$5.3mmHg p<0.01) and group III(72$\pm$5.6mmHg p<0.025) as compared with group I (44.2$\pm$4.6mmHg). Percentage recovery of LVDP at the reperfusion was the highest in group II(123.3%) Percentage recovery of coronary flow at the equilibrium reperfusion were higher in group II(310%, 270%) group III(230%, 290%) group IV(310%, 280%) as compared with group I (100%) respectively. Myocadial LDH level was significant lower in group IV(33495$\pm$1802 IU/gm p<0.04) as compared with group I(48767$\pm$1421 IU/gm) Myocadial CK-MB level was significant higher in group II(74820$\pm$1421 IU/gm) compared with group I (45450$\pm$1737 IU/gm) Myocadial ADA level was significant higher group IV(1215$\pm$8 IU/gm p<0.05) compared with group I(125$\pm$15 IU/gm) but there was no significant difference between group I and group II ,III, IV in changes of coronary effluent LDH, a-HBD levels. Conclusion: C-AMP PDSI solely appears to have a better effect on myocardial preservation after ischemia than NBT but with no synergistic effect and it could keep CK-MB leve high in myocardial tissues.

• The Korean Journal of Physiology and Pharmacology
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• v.2 no.6
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• pp.733-742
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• 1998

Background: We have previously reported that not only cGMP but also 8-Br-cGMP or 8-pCPT-cGMP, specific and potent stimulators of cGMP-dependent protein kinase (cGMP-PK), increased basal L-type calcium current $(I_{Ca})$ in rabbit ventricular myocytes. Our findings in rabbit ventricular myocytes were entirely different from the earlier findings in different species, suggesting that the activation of cGMP-PK is involved in the facilitation of $I_{Ca}}$ by cGMP. However, there is no direct evidence that cGMP-PK can stimulate $I_{Ca}}$ in rabbit ventricular myocytes. In this report, we focused on the direct effect of cGMP-PK on $I_{Ca}}$ in rabbit ventricular myocytes. Methods and Results: We isolated single ventricular myocytes of rabbit hearts by using enzymatic dissociation. Regulation of $I_{Ca}}$ by cGMP-PK was investigated in rabbit ventricular myocytes using whole-cell voltage clamp method. $I_{Ca}}$ was elicited by a depolarizing pulse to +10 mV from a holding potential of -40 mV. Extracellular 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate (8-pCPT-cGMP), potent stimulator of cGMP-dependent protein kinase (cGMP-PK), increased basal $I_{Ca}}$. cGMP-PK also increased basal $I_{Ca}}$. The stimulation of basal $I_{Ca}}$ by cGMP-PK required both 8-Br-cGMP in low concentration and intracellular ATP to be present. The stimulation of basal $I_{Ca}}$ by cGMP-PK was blocked by heat inactivation of the cGMP-PK and by bath application of 8-(4-chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer (Rp-pCPT-cGMP), a phosphodiesterase-resistant cGMP-PK inhibitor. When $I_{Ca}}$ was increased by internal application of cGMP-PK, IBMX resulted in an additional stimulation of $I_{Ca}}$. In the presence of cGMP-PK, already increased $I_{Ca}}$ was potentiated by bath application of isoprenaline or forskolin or intracellular application of cAMP. Conclusions: We present evidence that cGMP-PK stimulated basal $I_{Ca}}$ by a direct phosphorylation of L-type calcium channel or associated regulatory protein in rabbit ventricular myocytes.

• Tuberculosis and Respiratory Diseases
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• v.81 no.4
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• pp.299-304
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• 2018

Background: Roflumilast is the only approved oral phosphodiesterase-4 inhibitor for the treatment of severe chronic obstructive pulmonary disease (COPD) in patients with chronic bronchitis and a history of frequent exacerbations. The purpose of this study was to examine the incidence of adverse effects associated with roflumilast treatment in a real-world setting. Further, we compared the incidence of adverse effects and the discontinuation rate among patients receiving different doses. Methods: We identified all outpatients diagnosed with COPD at Seoul St. Mary's Hospital between May 2011 and September 2016 and retrospectively reviewed their medical records. Roflumilast was prescribed to patients in doses of $500{\mu}g$ and $250{\mu}g$. Results: A total of 269 COPD patients were prescribed roflumilast in our hospital during the study period. Among them, 178 patients were treated with $500{\mu}g$ and 91 patients were treated with $250{\mu}g$. The incidence of adverse effects was 38.2% in the $500{\mu}g$ group and 25.3% in the $250{\mu}g$ group (p=0.034). The discontinuation rate of roflumilast was 41.6% (n=74) in the $500{\mu}g$ group and 23.1% (n=21) in the $250{\mu}g$ group (p=0.003). When adjusted by age, sex, smoking status, and lung function, $500{\mu}g$ dose was significantly associated with the discontinuation of roflumilast (odds ratio, 2.87; p<0.001). Conclusion: There was a lower incidence of adverse effects and discontinuation among patients treated with $250{\mu}g$ compared with $500{\mu}g$ dose. Further studies regarding the optimal dose of roflumilast are required.

• Clinical and Experimental Reproductive Medicine
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• v.46 no.4
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• pp.173-177
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• 2019

Objective: We investigated the clinical characteristics of men with testosterone replacement therapy (TRT)-induced hypogonadism and its effect on assisted reproductive technology (ART) in infertile couples. Methods: This study examined the records of 20 consecutive male patients diagnosed with azoospermia or severe oligozoospermia (< 5 × 10⁶/mL) who visited a single infertility center from January 2008 to July 2018. All patients were treated at a primary clinic for erectile dysfunction or androgen deficiency symptoms combined with low serum testosterone. All men received a phosphodiesterase 5 inhibitor and TRT with testosterone undecanoate (Nebido^®) or testosterone enanthate (Jenasteron^®). Patients older than 50 years or with a chronic medical disease such as diabetes were excluded. Results: The mean age of patients was 37 years and the mean duration of infertility was 16.3 ± 11.6 months. At the initial presentation, eight patients had azoospermia, nine had cryptozoospermia, and three had severe oligozoospermia. Serum follicle-stimulating hormone levels were below 1.0 mIU/mL in most patients. Three ongoing ART programs with female factor infertility were cancelled due to male spermatogenic dysfunction; two of these men had normal semen parameters in the previous cycle. After withholding TRT, serum hormone levels and sperm concentrations returned to normal range after a median duration of 8 months. Conclusion: TRT with high-dose testosterone can cause spermatogenic dysfunction due to suppression of the hypothalamic-pituitary-testicular axis, with adverse effects on infertility treatment programs. TRT is therefore contraindicated for infertile couples attempting to conceive, and the patient's desire for fertility must be considered before initiation of TRT in a hypogonadal man.

• Journal of Pharmaceutical Investigation
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• v.40 no.2
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• pp.117-123
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• 2010

Ibudilast, 3-isobutyryl-2-isopropyrazolo[1,5-a]pyridine, is a nonselective inhibitor of cyclic nucleotide phosphodiesterase (PDE). It preferentially inhibits PDE 3A, PDE4, PDE10 and PDE11 as well as a number of the other PDE families, albeit to a lesser extent. Ibudilast is used clinically to treat bronchial asthma and cerebrovascular disorders. Thes e clinical uses are based on the ability of ibudilast to inhibit platelet aggregation, improve cerebral blood flow and attenuate allergic reactions. The purpose of the present study was to evaluate the bioequivalence of two ibudilast capsules, Ketas capsule (Handok Pharmaceuticals Co., Ltd.) and Pinatos capsule (Sam Chun Dang Pharm. Co., Ltd.), according to the guidelines of the Korea Food and Drug Administration (KFDA). The in vitro release of ibudilast from the two ibudilast formulations was tested using KP Apparatus method with various dissolution media. Twenty six healthy male subjects, 23.31${\pm}$1.09 years in age and 70.45${\pm}$8.51 kg in body weight, were divided into two groups and a randomized $2{\times}2$ cross-over study was employed. After a single capsule containing 10 mg as ibudilast was orally administered, blood samples were taken at predetermined time intervals and the concentrations of ibudilast in serum were determined using HPLC/UV detector. The dissolution profiles of two formulations were similar in all tested dissolution media. The pharmacokinetic parameters such as $AUC_t$, $C_{max}$ and $T_{max}$ were calculated, and computer programs (Equiv Test and K-BE Test 2002) were utilized for the statistical analysis of the parameters using logarithmically transformed $AUC_t$, $C_{max}$ and untransformed $T_{max}$. The results showed that the differences between two formulations based on the reference drug, Ketas, were 6.99%, -2.48% and 9.93% for $AUC_t$, $C_{max}$ and $T_{max}$, respectively. There were no sequence effects between two formulations in these parameters. The 90% confidence intervals using logarithmically transformed data were within the acceptance range of log 0.8 to log 1.25 (e.g., log 0.8791~log 1.1861 and log 0.8347~log 1.1199 for $AUC_t$ and $C_{max}$, respectively). Thus, the criteria of the KFDA bioequivalence guideline were satisfied, indicating Pinatos capsule was bioequivalent to Ketas capsule.

• Journal of the Korean Society of Food Science and Nutrition
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• v.45 no.4
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• pp.484-491
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• 2016

The present study investigated the effect of Sinetrol-XPur (polyphenolic Citrus spp. and Paullinia cupana Kunth dry extract) and defined the action mode for cyclic adenosine monophosphate (cAMP)-dependent uncoupling protein (UCP)-2 activation. Leptin-deficient obese mice were treated with two different doses, 100 mg/kg body weight (BW) and 300 mg/kg BW of each AIN93G supplement, for 7 weeks. Treatment of obese mice with both low and high doses of Sinetrol-XPur significantly reduced body weight gain compared to control obese mice. White adipose tissue weight of mice was reduced by 30.96% in high dose-supplemented groups. Serum total cholesterol and triglyceride were reduced by a high dose of Sinetrol-XPur by 20.02% and 30.96%, respectively. Serum level of high density lipoprotein (HDL) was significantly increased by treatment with both doses, as the ratio of HDL to low density lipoprotein increased by 138.78% and 171.49%, respectively. Regarding expression of biochemical factors related to lipid metabolism, fatty acid synthase significantly decreased and UCP-2 increased upon treatment with a high dose of Sinetrol-XPur, but there was no significant difference in lipoprotein lipase and hormone-sensitive lipase. To define cellular mechanism, intracellular cAMP levels in 3T3-L1 adipocytes significantly increased in a dose-dependent manner over the range of $50{\sim}250{\mu}m/mL$. The phosphodiesterase (PDE) inhibitor 3-isobutyl-1-methylxanthine clearly blocked cAMP, suggesting that Sinetrol-XPur promotes lipolysis of adipocytes through inhibition of cAMP-dependent PDE, resulting in induction of cAMP response element binding protein and UCP-2. These results suggest that Sinetrol-XPur supplementation is a viable option for reducing body weight and fat by improving serum lipid profiles and genetic expression of lipid metabolic factors, especially activation of cAMP-dependent UCP-2.