The effects of direct red bull administration to isolated hearts of trained and untrained rats who regularly consumed or did not consume energy drink: Focus on cardiodynamics and oxidative stress

Energy drinks (EDs) contain caffeine and other active ingredients which affect cardiovascular system. The aims of this study were to examine direct effects of Red Bull (RB) on cardiodynamics and oxidative stress in isolated hearts of rats. The rats were divided into four groups: Untrained rats who never consumed ED (dEDUT); untrained rats who consumed ED 5 days a week during 4 weeks (ch+dED-UT); rats trained 5 times a week for 4 weeks, but did not consume ED (dED-T); rats trained and consumed ED 5 times a week for 4 weeks (ch+dED-T). After sacrificing, hearts were isolated and perfused according to Langendorff technique. Through the isolated heart of all rats in each group, RB was administered. The parameters of cardiac function were recorded, and the levels of prooxidants were measured in the coronary effluent during coronary autoregulation. Rats in ch+dED-UT group had significantly lower rates of myocardial contraction and relaxation compared to rats in dED-UT group. The same effect was recorded in the dED-T group compared to dED-UT group. The levels of hydrogen peroxide were significantly higher in trained rats. Rats in ch+dED-T group also had significantly higher levels of superoxide anion radical and index of lipid peroxidation, as well as lower levels of nitrites when compared to ch+dED-UT group, while opposite effect was recorded in rats in dED-T group compared to dEDUT group. The RB could have a potentially negative inotropic effect in chronic consumers. Prooxidative effect of RB was most pronounced in trained chronic consumers

Kardiorespiratorni fitnes i njegov značaj u reakcijama kortizola i laktata prilikom zimskih i letnjih marševa

Background: The influence of homeostatically regulated physiological processes, including cardiorespiratory fitness (VO2max), on the response to physical stressors such as acclimatisation and marching, remains understudied. We aimed to investigate the effects of summer and winter acclimatisation and marching on cortisol levels and blood lactate, to gain insight into the role of these physiological processes in the stress response. Methods: Two groups of young Europeans, classified as poor (PCF; n=9) and good physical condition (GCF; n=21), based on a VO2max threshold of 40 mL O2/ kg/min, underwent 2-h march (6–7 km/h) in winter (5 ∘C) and summer (32 ∘C). Commercial tests, UniCel DxI Access Cortisol assay and EKF Biosen Clinic/GP assay were used for cortisol and lactate blood measurements (morning samples and those taken immediately after marches), respectively. Results: Basal cortisol levels were significantly higher at 5 °C than at 32 °C (PCF group: P=0.0079; cortisol dropped after the march at 5 °C in both groups, but increased at 32 °C only in PCF. Basal lactate levels were higher at 32 °C only in the GCF group (compared to PCF, P=0.0014) and post-marching (compared to basal values, P=0.0002). Conclusion: Cold exposure elicits a more significant stress response, based on higher basal cortisol levels, in individuals with worse physical fitness. Anaerobe metabolism prevails in participants with better physical fitness exposed to high ambient temperature based on increased basal and post-marching lactate levels. The study is significant for individual training/performance optimisation as it indicates the association between physiological stress responses and individual physical fitness levels.Uvod: Uticaj homeostatski regulisanih fiziolo{kih procesa, uklju~uju}i kardiorespiratornu kondiciju (VO2max), na odgovor na fizi~ke stresore poput aklimatizacije i mar{i- ranja, ostaje nedovoljno prou~en. Cilj istra`ivanja je bio i da se ispita uticaj aklimatizacije i mar{iranja tokom leta i zime na nivoe kortizola i laktoze u krvi, pru`aju}i uvid u ulogu ovih fiziolo{kih procesa u odgovoru na stres. Metode: Dve grupe mladih Evropljana, klasifikovane kao osobe sa slabom (PCF; n=9) i dobrom fizi~kom kondicijom (GCF; n=21), na osnovu praga VO2max od 40 mL O 2/kg/min, su bile izlo`ene dvosatnom mar{u (6–7 km/h) u dva navrata, zimi na 5 °C i leti, na 32 °C. U uzorcima krvi (jutarnji i neposredno nakon mar{a) su odre|ivani nivoi kortizola i laktata komercijalnim testovima, UniCel DxI Access Cortisol i EKF Biosen Clinic/GP. Rezultati: Bazalni nivoi kortizola su bili zna~ajno vi{i na 5 °C nego na 32 °C (u PCF grupi: P=0,0079); nakon mar{i- ranja na 5 °C kortizol opada u obe grupe a pove}an je na 32 °C samo u PCF grupi. Bazalni nivoi laktoze bili su vi{i na 32 °C samo u GCF grupi (porede}i sa PCF grupom, P=0,0014) i nakon mar{iranja (porede}i sa bazalnim vred- nostima, P=0,0002)

The effects of valsartan on cardiac function and pro-oxidative parameters in the streptozotocin-induced diabetic rat heart

© 2020, University of Kragujevac, Faculty of Science. All rights reserved. Diabetes mellitus is a major risk factor for cardiovascular diseases, while cardiovascular diseases are a leading cause of morbidity and mortality worldwide. The renin–angiotensin– aldosterone system controls renal, cardiovascular, adrenal function and regulates fluid and electrolyte balance as well as blood pressure. Because of his role, inhibition of renin-angiotensin-aldosteron system is another therapy approach that reduces the risk of diabetes and cardiovascular disease. In this study, our goal was to evaluate effect of valsartan,as inhibitor of angiotensin II receptor type 1, on cardiac tissue and function, with focus on cardiodynamic and oxidative stress. The present study was carried out on 20 adult male Wistar albino rats (8 week old and with body masses of 180-200 g). Rats were divided randomly into 2 groups (10 animals per group). Healthy animals treated with 1 μM of valsartan and streptozotocin-induced diabetic animals perfused with 1 μM of valsartan 4 weeks after the induction of diabetes. Our results demonstrated that acute application of valsartan has different effect on cardiodynamics in rat heart of diabetic and healthy animals but did not improve cardiac function in hy-perglycemia-induced changes. A challenge for further investi-gations are studies with chronic or acute administration, alone or in combination with other angiotensin-converting-enzyme inhibitor in various models of diabetes

Pituitary Hyperplasia, Hormonal Changes and Prolactinoma Development in Males Exposed to Estrogens — An Insight From Translational Studies

Estrogen signaling plays an important role in pituitary development and function. In sensitive rat or mice strains of both sexes, estrogen treatments promote lactotropic cell proliferation and induce the formation of pituitary adenomas (dominantly prolactin or growth-hormone-secreting ones). In male patients receiving estrogen, treatment does not necessarily result in pituitary hyperplasia, hyperprolactinemia or adenoma development. In this review, we comprehensively analyze the mechanisms of estrogen action upon their application in male animal models comparing it with available data in human subjects. Sex-specific molecular targets of estrogen action in lactotropic (PRL) cells are highlighted in the context of their proliferative and secretory activity. In addition, putative effects of estradiol on the cellular/tumor microenvironment and the contribution of postnatal pituitary progenitor/stem cells and transdifferentiation processes to prolactinoma development have been analyzed. Finally, estrogen-induced morphological and hormone-secreting changes in pituitary thyrotropic (TSH) and adrenocorticotropic (ACTH) cells are discussed, as well as the putative role of the thyroid and/or glucocorticoid hormones in prolactinoma development, based on the current scarce literature