• Clinical and Experimental Reproductive Medicine
• /
• v.48 no.3
• /
• pp.189-193
• /
• 2021

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a novel coronavirus found in China in 2019. The disease caused by SARS-CoV-2, coronavirus disease 2019 (COVID-19), has been found to be closely related to the cells that secrete angiotensin-converting enzyme 2 (ACE2). ACE2 is involved in the renin-angiotensin system and is widely secreted in several tissues, including the testis, which has raised concerns because organs with high expression of the ACE2 receptor are susceptible to infection. Analyses have shown that in testicular cells, such as spermatogonia, seminiferous duct cells, Sertoli cells, and Leydig cells, there is a high expression level of ACE2. Therefore, SARS-CoV-2 may damage male reproductive tissues and cause infertility. Since male infertility is an important problem, scientists are evaluating whether COVID-19 may influence male infertility through the ACE2 receptor.

• The Korean Journal of Physiology
• /
• v.28 no.2
• /
• pp.197-202
• /
• 1994

The present study was aimed to determine if endogenous L-arginine-nitric oxide (NO) pathway has central, rather than peripheral, mechanisms in blood pressure regulation. Arterial blood pressure and heart rate responses to acute inhibition of the t-arginine-NO pathway were examined in rats anesthetized with thiopental (50 mg/kg, IP). An intracerebroventricular (ICV) cannula was placed in the left lateral ventricle. The right femoral artery was cannulated to measure arterial blood pressure and the vein to serve as an infusion route. $N^G-nitro-L-arginine$ methyl ester (L-NAME) was infused either intracerebroventricularly or intravenously. ICV infusion $(1.25\;{\mu}L/min)$ of L-NAME $(20\;or\;100\;{\mu}g/kg)$ per minute for 60 min) increased the mean arterial pressure and heart rate. Plasma renin concentrations(PRC) were significantly lower in L-NAME-infused group than in the control. L-Arginine $(60\;{\mu}g/min,\;ICV)$ prevented the pressor response to ICV L-NAME. The pressor response was not affected by simultaneous intravenous infusion of saralasin, but was abolished by hexamethonium treatment. Intravenous infusion $(40\;{\mu}L/min,\;10{\sim}100\;{\mu}g/kg\;per\;minute\;for\;60\;min)$ also increased blood pressure, while it decreased heart rate. These results indicate that endogenous L-arginine-NO pathway has separate central and peripheral mechanisms in regulating the cardiovascular function. The central effect may not be mediated via activation of renin-angiotensin system, but via, at least in part, activation of the sympathetic outflow.

• Journal of Integrative Natural Science
• /
• v.10 no.2
• /
• pp.74-77
• /
• 2017

Bradykinin receptor B2 (B2R) is a GPCR protein which binds with the inflammatory mediator hormone bradkynin. Kallidin, a decapeptide, also signals through this receptor. B2R is crucial in the cross-talk between renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS) and in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Thus the structural study of the receptor becomes important. We have predicted the peptide structures of Bradykinin and Kallidin from their amino acid sequences and the structures were docked with the receptor structure. The results obtained from protein-protein docking could be helpful in studying the B2R structural features and in the pathophysiology in various diseases related to it.

• Journal of Integrative Natural Science
• /
• v.9 no.4
• /
• pp.234-240
• /
• 2016

Bradykinin receptor B2, a GPCR protein, binds with the inflammatory mediator hormone bradkynin. It plays an important role in cross-talk between the renin-angiotensin system (RAS) and the kinin-kallikrein system (KKS). Also, it is involved in many processes including vasodilation, edema, smooth muscle spasm and pain fiber stimulation. Hence, studuying the structural features of the receptor becomes important. But the unavailability of the three dimensional structure of the protein makes the analysis difficult. Hence we have performed the homology modelling of Bradykinin receptor B2 with 5 different templates. 25 different homology models were constructed. Two best models were selected based on the model validation. The developed models could be helpful in analysing the structural features of Bradykinin receptor B2 and in pathophysiology of various disorders related to them.

• Journal of Physiology & Pathology in Korean Medicine
• /
• v.30 no.2
• /
• pp.95-100
• /
• 2016

The aim of the present study is to investigate the hypotensive effect of Mantidis ootheca (WMO), Rosa laevigata (WIC), and Imperata cylindrica (WRL) in renovascular hypertension rats. Experimental hypertension model is 2-kidney and 1-clip (2K1C) induced rats. 2K1C rats were treated with WMO, WIC, and WRL at dose of 100 mg/kg/day orally for 3 weeks, respectively. Treatment groups with WMO, WIC, and WRL significantly lowered blood pressure. Interestingly, WMO, WIC, and WRL ameliorated endothelium-dependent and independent vascular relaxation in the phenylephrine-precontracted thoracic aorta in hypertension models. In addition, 2K1C-induced hypertension model increased plasma renin activity, however, WMO, WIC, and WRL attenuated those activities. These results suggest that WMO, WIC, and WRL ameliorates vascular dysfunction in 2K1C-induced hypertension models via the regulation of nitric oxide and renin-angiotensin-aldosterone system.

• Applied Microscopy
• /
• v.39 no.2
• /
• pp.81-87
• /
• 2009

Diabetic retinopathy is one of major complications of diabetes mellitus, which is associated with the dysfunction of retina. It has been reported that the onset of diabetic retinopathy is related to the activation of renin-angiotensin system (RAS). Angiotensin converting enzyme (ACE), which converts angiotensin I into angiotensin II, is a key component of RAS. Among many growth factors, vascualr endothelial growth factor (VEGF) is an important cytokine in the neovasculization of retina, which is a characteristics of diabetic retinopathy. However, the relationship between ACE and VEGF was not elucidated in diabetic retinopathy. Thus, this study was conducted to examine the protective effect of captopril, an ACE inhibitor, in the retina of streptozotocin (STZ)-treated diabetic rats. In present study, STZ-treated diabetic rats exhibited the increase of VEGF levels in serum and retina. The serum levels of VEGF in STZ-treated diabetic rats was not blocked by the treatment of captopril. However, the retina levels of VEGF in STZ-treated diabetic rats was blocked by the treatment of captopril, suggesting the local action of captopril in retina. Immunohistochemical analysis also revealed that the retina of STZ-treated diabetic rats manifested the increase of ganglion cell layers, outer nuclear layers, and inner nuclear layers, which were also prevented by the treatment of captopril. In conclusion, captopril prevented the expression of VEGF in the retina of STZ-treated diabetic rats.

• BMB Reports
• /
• v.31 no.5
• /
• pp.459-467
• /
• 1998

A new set of functional group interaction energy descriptors relevant to the ACE (Angiotensin-Converting Enzyme) inhibitory peptide, QSAR (Quantitative Structure Activity Relationships), is presented. The functional group interaction energies approximate the charged interactions and distances between functional groups in molecules. The effective energies of the computationally derived geometries are useful parameters for deriving 3D-QSAR models, especially in the absence of experimentally known active site conformation. ACE is a regulatory zinc protease in the renin-angiotensin system. Therapeutic inhibition of this enzyme has proven to be a very effective treatment for the management of hypertension. The non bond interaction energy values among functional groups of six-feature of ACE inhibitory peptides were used as descriptor terms and analyzed for multivariate correlation with ACE inhibition activity. The functional group interaction energy descriptors used in the regression analysis were obtained by a series of inhibitor structures derived from molecular mechanics and semi-empirical calculations. The descriptors calculated using electrostatic and steric fields from the precisely defined functional group were sufficient to explain the biological activity of inhibitor. Application of the descriptors to the inhibition of ACE indicates that the derived QSAR has good predicting ability and provides insight into the mechanism of enzyme inhibition. The method, functional group interaction energy analysis, is expected to be applicable to predict enzyme inhibitory activity of the rationally designed inhibitors.

• Journal of Biomedical and Translational Research
• /
• v.19 no.4
• /
• pp.86-91
• /
• 2018

Angiotensin receptor blockers, such as telmisartan, are considered effective in the treatment of hypertension and proteinuria due to chronic kidney disease (CKD) in cats. It selectively blocks the $AT_1$ receptor and does not affect the $AT_2$ receptor, thus effectively blocking the activity of the renin angiotensin aldosterone system. This study aims to compare over time the changes in various indicators, including systemic hypertension and proteinuria, before and after the administration of telmisartan in cats with CKD. Decrease in blood pressure (BP) (p<0.001) and urine protein to creatinine (UP/C) ratio (p<0.001) were found to be statistically significant over time after the administration of telmisartan. BP and the UP/C ratio were $160{\pm} 22.2$ and $0.50{\pm}0.647$ before telmisartan administration (Day 0), $150{\pm}21.0$ and $0.27{\pm}0.487$ on the 30th day (Day 30), $150{\pm}17.0$ and $0.25{\pm}0.376$ on the 60th day (Day 60), and $140{\pm}17.8$ and $0.15{\pm}0.233$ on the 90th day (Day 90) after administration, respectively. BP and UP/C were statistically significantly lower in cats with CKD over time at each time point from Day 0 to Day 90 at 30 day intervals. Especially after 90 days of telmisartan administration, the improvement of BP and UP/C were estimated to be about 20 mmHg and 0.35, respectively. In conclusion, the oral administration of telmisartan to cats with CKD is effective in improving BP and proteinuria, which has a positive effect on long-term survival in cats with CKD.

• Journal of Dairy Science and Biotechnology
• /
• v.27 no.2
• /
• pp.17-23
• /
• 2009

In the light of the increasing concern over the prevalence of osteoporosis, hypertension, diabetes mellitus, we performed this study to review the correlation between the dietary calcium and vitamin D intake and these diseases. To this end, we investigated the effects of dietary calcium and vitamin D on these diseases. We observed that the intake of dietary calcium and vitamin D had a negative correlation with the incidences of osteoporosis, hypertension, and diabetes mellitus. Further, the intake of these two nutrients is expected to improve related mechanisms such as the renin-angiotensin system. Therefore, we suggest that dietary calcium and vitamin D have a beneficial effect on these diseases.

• Clinical and Experimental Pediatrics
• /
• v.50 no.5
• /
• pp.430-435
• /
• 2007

Even though we drink and excrete water without recognition, the amount and the composition of body fluid remain constant everyday. Maintenance of a normal osmolality is under the control of water balance which is regulated by vasopressin despite sodium concentration is the dominant determinant of plasma osmolality. The increased plasma osmolality (hypernatremia) can be normalized by the concentration of urine, which is the other way of gaining free water than drinking water, while the low plasma osmolality (hyponatremia) can be normalized by the dilution of urine which is the only regulated way of free water excretion. On the other hand, volume status depends on the control of sodium balance which is regulated mainly by renin-angiotensin-aldosterone system, through which volume depletion can be restored by enhancing sodium retention and concomitant water reabsorption. This review focuses on the urine concentration and dilution mechanism mediated by vasopressin and the associated disorders; diabetes insipidus and syndrome of inappropriate antidiuretic hormone secretion.