The Experts below are selected from a list of 15 Experts worldwide ranked by ideXlab platform
Frances M Huntley - One of the best experts on this subject based on the ideXlab platform.
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the presence of Cortisol Receptors in the human amnion
The Journal of Steroid Biochemistry and Molecular Biology, 1997Co-Authors: Melvin Weisbart, Frances M HuntleyAbstract:Cytosol extracts of human amnion tissue contained high affinity binding of Cortisol (Ka=2.48+/-1.06 x 10(9) M(-1); n = 30) and low capacity binding of Cortisol (Nmax=279+/-15.5 fmol mg(-1) protein). Kinetic studies of Cortisol binding resulted in a similar value of Ka to that obtained by Scatchard analysis. Nuclear extracts of amnion tissue contained high affinity binding of Cortisol (Ka=5.8+/-1.91 x 10(7) M[-1]) and low binding capacity (Nmax=91.4+/-21.4 fmol mg(-1) protein). Ka values were an order of magnitude higher in cytosol than in blood serum when amnion and blood were obtained from the same individuals. Differences in competitive ligand binding, especially dexamethasone, were observed between the amnion receptor and transcortin in serum. Gel permeation chromatography gave only one peak at 320 kDa for amnion receptor and only one peak at 48 kDa for transcortin from serum. When amnion tissue was incubated with or without Cortisol, cytosol receptor activity was significantly lower in Cortisol treated tissue than in control. The nuclear extracted receptor activity was significantly higher in Cortisol treated tissue than control. The Ka values from Cortisol treated tissue were significantly lower from control. Together the data support the presence of a specific Cortisol receptor in the human amnion that is different from transcortin.
Melvin Weisbart - One of the best experts on this subject based on the ideXlab platform.
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the presence of Cortisol Receptors in the human amnion
The Journal of Steroid Biochemistry and Molecular Biology, 1997Co-Authors: Melvin Weisbart, Frances M HuntleyAbstract:Cytosol extracts of human amnion tissue contained high affinity binding of Cortisol (Ka=2.48+/-1.06 x 10(9) M(-1); n = 30) and low capacity binding of Cortisol (Nmax=279+/-15.5 fmol mg(-1) protein). Kinetic studies of Cortisol binding resulted in a similar value of Ka to that obtained by Scatchard analysis. Nuclear extracts of amnion tissue contained high affinity binding of Cortisol (Ka=5.8+/-1.91 x 10(7) M[-1]) and low binding capacity (Nmax=91.4+/-21.4 fmol mg(-1) protein). Ka values were an order of magnitude higher in cytosol than in blood serum when amnion and blood were obtained from the same individuals. Differences in competitive ligand binding, especially dexamethasone, were observed between the amnion receptor and transcortin in serum. Gel permeation chromatography gave only one peak at 320 kDa for amnion receptor and only one peak at 48 kDa for transcortin from serum. When amnion tissue was incubated with or without Cortisol, cytosol receptor activity was significantly lower in Cortisol treated tissue than in control. The nuclear extracted receptor activity was significantly higher in Cortisol treated tissue than control. The Ka values from Cortisol treated tissue were significantly lower from control. Together the data support the presence of a specific Cortisol receptor in the human amnion that is different from transcortin.
Stephen D Mccormick - One of the best experts on this subject based on the ideXlab platform.
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endocrine control of osmoregulation in teleost fish
Integrative and Comparative Biology, 2001Co-Authors: Stephen D MccormickAbstract:As the primary link between environmental change and physiological response, the neuroendocrine system is a critical part of osmoregulatory adaptations. Cortisol has been viewed as ‘the’ seawater-adapting hormone in fish and prolactin as ‘the’ fresh water adapting hormone. Recent evidence indicates that the growth hormone/insulin-like growth factor I axis is also important in seawater adaptation in several teleosts of widely differing evolutionary lineages. In salmonids, growth hormone acts in synergy with Cortisol to increase seawater tolerance, at least partly through the upregulation of gill Cortisol Receptors. Cortisol under some conditions may promote ion uptake and interacts with prolactin during acclimation to fresh water. The osmoregulatory actions of growth hormone and prolactin are antagonistic. In some species, thyroid hormones support the action of growth hormone and Cortisol in promoting seawater acclimation. Although a broad generalization that holds for all teleosts is unlikely, our current understanding indicates that growth hormone promotes acclimation to seawater, prolactin promotes acclimation to fresh water, and Cortisol interacts with both of these hormones thus having a dual osmoregulatory function.
David H Evans - One of the best experts on this subject based on the ideXlab platform.
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cell signaling and ion transport across the fish gill epithelium
Journal of Experimental Zoology, 2002Co-Authors: David H EvansAbstract:A large array of circulating and local signaling agents modulate transport of ions across the gill epithelium of fishes by either affecting transport directly or by altering the size and distribution of transporting cells in the epithelium. In some cases, these transport effects are in addition to cardiovascular effects of the same agents, which may affect the perfusion pathways in the gill vasculature and, in turn, affect epithelial transport indirectly. Prolactin is generally considered to function in freshwater, because it is the only agent that allows survival of some hypophysectomized fish species in freshwater. It appears to function by either reducing branchial permeability, Na,K-activated ATPase activity, or reducing the density of chloride cells. Cortisol was initially considered to produce virtually opposite effects (e.g., stimulation of Na,K-activated ATPase and of chloride cell size and density), but more recent studies have found that this steroid stimulates ionic uptake in freshwater fishes, as well as the activity of H-ATPase, an enzyme thought to be central to ionic uptake. Thus, Cortisol may function in both high and low salinities. Growth hormone and insulin-like growth factor appear to act synergistically to affect ion regulation in seawater fishes, stimulating both Na,K-activated ATPase and Na-K-2Cl co-transporter activity, and chloride cell size, independent of their effects on growth. Some of the effects of the GH–IGF axis may be via stimulation of the number of Cortisol Receptors. Thyroid hormones appear to affect seawater ion regulation indirectly, by stimulating the GH–IGF axis. Natriuretic peptides were initially thought to stimulate gill ionic extrusion, but recent studies have not corroborated this finding, so it appears that the major mode of action of these peptides may be reduction of salt loading by inhibition of oral ingestion and intestinal ionic uptake. Receptors for both arginine vasotocin and angiotensin have been described in the gill epithelium, but their respective roles and importance in fish ion regulation remains unknown. The gill epithelium may be affected by both circulating and local adrenergic agents, and a variety of studies have demonstrated that stimulation of α-adrenergic versus β-adrenergic Receptors produces inhibition or stimulation of active salt extrusion, respectively. Local effectors, such as prostaglandins, nitric oxide, and endothelin, may affect active salt extrusion as well as gill perfusion. Recent studies have suggested that the endothelin inhibition of salt extrusion is actually mediated by the release of both NO and prostaglandins. It is hoped that modern molecular techniques, combined with physiological measurements, will allow the dissection of the relative roles in ion transport across the fish gill epithelium of this surprisingly large array of putative signaling agents. © 2002 Wiley-Liss, Inc.
Salvador Alicia - One of the best experts on this subject based on the ideXlab platform.
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Acute Cortisol levels and memory performance in older people with high and normal Body Mass Index
'Cambridge University Press (CUP)', 2019Co-Authors: Pulópulos Tripiana Matias, Puig Perez Sara, Hidalgo Vanesa, Montoliu Teresa, Salvador AliciaAbstract:Previous studies have shown that healthy older adults may be less sensitive to the effects of acute Cortisol levels on memory performance than young adults. Importantly, being overweight has recently been associated with an increase in both Cortisol concentration and Cortisol Receptors in central tissues, suggesting that Body Mass Index (BMI) may contribute to differences in the relationship between memory and acute Cortisol. This study investigates the role of BMI in the relationship between memory performance and acute Cortisol levels in older people (M = 64.70 years; SD = 4.24). We measured Cortisol levels and memory performance (working memory and declarative memory) in 33 participants with normal BMI (normal BMI = 18.50-24.99) and 36 participants with overweight BMI (overweight BMI = 25-29.99). Overweight BMI participants showed worse performance on word-list learning (p = .036, 95% CI [0.08, 2.18], eta(2)(p) = 0.07). Higher Cortisol levels were related to higher proactive interference (beta = .364, p = .016, 95% CI [0.07, 0.66]), and BMI did not moderate any of the relationships investigated. In accordance with previous studies, our results show worse memory performance in individuals with overweight BMI. However, our results do not support the idea that memory performance in older people with higher BMI may be more sensitive to differences in acute Cortisol levels than in older people with normal BMI. More research is needed to test this hypothesis with obese individuals (BMI > 30 Kg/cm(2))
