China 
Africa 
Explore chapters and articles related to this topic
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2023
Revati Phalkey, Naima Bradley, Alec Dobney, Virginia Murray, John O’Hagan, Mutahir Ahmad, Darren Addison, Tracy Gooding, Timothy W Gant, Emma L Marczylo, Caryn L Cox
Changes similar to Cushing’s Syndrome follow treatment with corticosteroids over a period of time in several common disease states. An excessive production of aldosterone leads to Conn’s disease, which is associated with muscular weakness, increased loss of potassium and water in the urine.
Antihypertensive Drugs: Controlling Blood Pressure
Published in Richard J. Sundberg, The Chemical Century, 2017
Goldblatt’s proposal triggered a search for renin. Around 1940, it became clear that the substance was a protease with high specificity. Renin is produced mainly in the kidney, initially as a 406 AA precursor. The active form is made by cleavage to remove 23 and 43 AA segments and glycosylation. Renin is produced in response to several factors, including Na+ flux and vascular pressure in the kidney. It is an aspartyl proteinase that cleaves the protein angiotensinogen to form the actual active substance, angiotensin-II (AT-II). In the 1950s, it was shown that there were two steps in the process, leading first to angiotensin-I (AT-I) a decapeptide and then to AT-II, an octapeptide. This implied that there was another enzyme involved in the conversion of AT-I to AT-II, called the angiotensin converting enzyme (ACE). Late in the 1950s, it was shown that AT-II functions by stimulating aldosterone secretion. Aldosterone is a critical factor in maintaining salt and fluid balance, as well as blood pressure.2 The polypeptides were made by synthesis at Ciba and became available for extensive studies.
Human physiology, hazards and health risks
Published in Stephen Battersby, Clay's Handbook of Environmental Health, 2016
David J. Baker, Naima Bradley, Alec Dobney, Virginia Murray, Jill R. Meara, John O’Hagan, Neil P. McColl, Caryn L. Cox
Changes similar to Cushing’s Syndrome follow treatment with corticosteroids over a period of time in several common disease states. An excessive production of aldosterone leads to Conn’s disease, which is associated with muscular weakness, increased loss of potassium and water in the urine.
Salivary aldosterone and cortisone respond differently to high- and low-psychologically stressful soccer competitions
Published in Journal of Sports Sciences, 2020
Timothy S. McHale, Wai-Chi Chee, Carolyn R. Hodges-Simeon, David T. Zava, Graham Albert, Ka-Chun Chan, Peter B. Gray
Aldosterone is produced in the zona glomerulosa of the adrenal cortex and increases during physically stressful contexts, such as exercise (Zorbas et al., 2001). It is involved in the regulation of blood pressure and fluid balance by acting on the kidneys to conserve salt and water by stimulating sodium and water reabsorption from the gut, and salivary and sweat glands, during physically demanding conditions (Bollag, 2014). Salivary aldosterone is closely associated with plasma aldosterone levels (Lichtenauer et al., 2016; Mcvie et al., 1979). Research on adults has shown that aldosterone levels significantly increase during physically taxing forms of exercise and competition, such as rally car races (Bollag, 2014; Del Rosso et al., 2016; Joëls & de Kloet, 2017; De Souza et al., 1989; Zorbas et al., 2001). Evidence also suggests that aldosterone may even decrease when both physical and psychosocial stress levels are low; among competitors in a non-physical, team, informal e-sports gaming competition, aldosterone significantly decreased following the game (Gray et al., 2018). These findings among adults imply that aldosterone is sensitive to intense physical stress; yet, the direction and magnitude of change may also be regulated by psychological stress (Apostolopoulou et al., 2014; Franklin et al., 2012; Hlavacova & Jezova, 2008a, 2008b; Segeda et al., 2017). More research is needed, however, to understand how aldosterone is regulated in competitive activities, like sports, during childhood.
Effects of whey protein in carbohydrate-electrolyte drinks on post-exercise rehydration
Published in European Journal of Sport Science, 2018
Liang Li, Feng-Hua Sun, Wendy Ya-Jun Huang, Stephen Heung-Sang Wong
An increase in plasma osmolality and a decrease in PV during exercise, along with significant BM loss, can trigger specific receptors in the adrenal cortex and posterior pituitary gland to promote the secretion of aldosterone and ADH (Kenefick et al., 2000; Stachenfeld et al., 1996). Aldosterone and ADH concentrations can be significantly increased with a dehydration level of 4% BM loss (Kenefick et al., 2000). In the current study, the aldosterone concentration increased from approximately 350 pg·mL−1 to 500 pg·mL−1 after the 60-min run. Previous studies have observed high aldosterone concentrations when participants consumed daily diets with relatively high protein contents because of the activated plasma renin activity after protein supplementation (Daniels & Hostetter, 1990; Lauridsen, Vase, Starklint, Bech, & Pedersen, 2010). A previous animal study reported that the concentrations of aldosterone and plasma sodium in rats was increased after the ingestion of milk protein solution or milk during post-exercise recovery, resulting in improved fluid retention (Ishihara et al., 2013). The CW-M and CW-H trials had higher aldosterone concentrations than the isocaloric CE-H trial at the end of recovery, which might enhance the reabsorption of sodium and water from the kidneys and improve fluid retention. However, the difference of aldosterone concentration was only observed at the end of recovery, indicating that this hormone may not have enough time to exert a significant effect on fluid balance, and further research is needed to clarify this issue. On the other hand, previous studies reported that protein ingestion also increases ADH levels (Daniels & Hostetter, 1990; Lauridsen et al., 2010). In the current study, the difference in ADH concentration was observed between the CW-H and CE-L trials after 1 h and 2 h of recovery, but no differences were observed among the CW-M, CW-H and CE-H isocaloric drinks. Therefore, it was difficult to clarify whether the energy density or whey protein affects ADH release in the current study, and the changes in ADH concentration were not the primary reason for the significant fluid retention after the ingestion of the CW-M or CW-H drink.
Fluid and electrolyte balance considerations for female athletes
Published in European Journal of Sport Science, 2022
Paola Rodriguez-Giustiniani, Nidia Rodriguez-Sanchez, Stuart D.R. Galloway
Sodium and water filter freely from the renal glomerular capillaries and undergo considerable reabsorption (usually more than 99%). Most sodium and water reabsorption (about 2/3rds) occurs in the proximal tube, but the primary hormonal regulation of reabsorption occurs in the collecting ducts. Sodium reabsorption is an active process happening in all tubular segments except the descending limb of the loop of Henle, and water reabsorption occurs by diffusion and is dependent upon sodium reabsorption. The kidneys also balance potassium intake with potassium excretion and are primarily responsible for maintaining total body potassium content. The main determinant of permeability, and consequently of water reabsorption, in the collecting tubes is the action of AVP (Hew-Butler, 2010). When AVP plasma concentration is high, the water permeability of the collecting tubes is increased. Water reabsorption is maximal, and the final urine volume is minimal (<1% of the filtered water). Without the action of AVP, the water permeability of the collecting tubes is very low and very little water is reabsorbed, allowing a greater amount of water left in the tubule to be excreted in the urine. Cardiovascular baroreceptors mediate posterior pituitary secretion of AVP with a low extracellular volume stimulating AVP secretion, and a high extracellular volume inhibiting it (Figure 1). AVP is also affected by osmoreceptors in the hypothalamus with a high perfusing osmolality stimulating AVP secretion, and a low osmolality inhibiting it (Perrier et al., 2013; Schrier, Berl, & Anderson, 1979; Stockand, 2010; Thornton, 2010). The RAAS also plays a crucial role in body water volume regulation through actions on electrolyte balance. Plasma angiotensin II (ANG II) is elevated during salt depletion and reduced when the individual is sodium replete. Elevation of ANG II induces increased secretion of aldosterone from the adrenal cortex which subsequently stimulates sodium reabsorption by the renal cortical collecting ducts. During exercise, there is primarily a stimulus for the release of AVP caused by an increase in osmolality and a decrease in plasma volume (Hew-Butler, 2010; Sollanek, Staab, Kenefick, & Cheuvront, 2020) particularly in situations where fluid losses are high, such as with exercise and heat stress.