Electrolyte Transport Mechanisms in Fish Intestine

1993 ◽  
pp. 1-25 ◽  
Author(s):  
Brahim Lahlou ◽  
Martine Avella
Keyword(s):  
Electrolyte Transport ◽  
Transport Mechanisms ◽  
Fish Intestine

Electrolyte transport in the renal collecting duct and its regulation by the renin–angiotensin–aldosterone system

2019 ◽  
Vol 133 (1) ◽  
pp. 75-82
Author(s):  
Osamu Yamazaki ◽  
Kenichi Ishizawa ◽  
Daigoro Hirohama ◽  
Toshiro Fujita ◽  
Shigeru Shibata
Keyword(s):  
Current Knowledge ◽  
Collecting Duct ◽  
Salt Transport ◽  
Electrolyte Transport ◽  
Intercalated Cells ◽  
Transport Mechanisms ◽  
Cortical Collecting Duct ◽  
Distal Nephron ◽  
Renin Angiotensin Aldosterone System ◽  
Renin Angiotensin

Abstract Distal nephron of the kidney plays key roles in fluid volume and electrolyte homeostasis by tightly regulating reabsorption and excretion of Na+, K+, and Cl−. Studies to date demonstrate the detailed electrolyte transport mechanisms in principal cells of the cortical collecting duct, and their regulation by renin–angiotensin–aldosterone system (RAAS). In recent years, however, accumulating data indicate that intercalated cells, another cell type that is present in the cortical collecting duct, also play active roles in the regulation of blood pressure. Notably, pendrin in β-intercalated cells not only controls acid/base homeostasis, but is also one of the key components controlling salt and K+ transport in distal nephron. We have recently shown that pendrin is regulated by the co-ordinated action of angiotensin II (AngII) and aldosterone, and at the downstream of AngII, mammalian target of rapamycin (mTOR) signaling regulates pendrin through inhibiting the kinase unc51-like-kinase 1 and promoting dephosphorylation of mineralocorticoid receptor (MR). In this review, we summarize recent advances in the current knowledge on the salt transport mechanisms in the cortical collecting duct, and their regulation by the RAAS.

Electrical potential profile in rabbit ileum: role of rheogenic Na transport.

1977 ◽  
Vol 232 (1) ◽  
pp. E5
Author(s):  
R C Rose ◽  
D L Nahrwold ◽  
M J Koch
Keyword(s):  
Active Transport ◽  
Electrical Potential ◽  
Electrolyte Transport ◽  
Potential Profile ◽  
Ion Concentration ◽  
Transport Mechanisms ◽  
Na Transport ◽  
Concentration Gradients ◽  
Rabbit Ileum ◽  
Cation Concentration

The electrical potential profile of rabbit ileum was investigated in vitro with the microelectrode technique. The transmural electrical potential difference (PD), designated psims, was immediately reduced by 60% upon cooling the tissue from 37 to 7 degrees C; the PD across the mucosal membrane (transmucosal PD, psimc) was simultaneously reduced by 37%. These electrical changes could not be attributed to alternations in either transmembrane ion concentration gradients or total tissue conductance. The psimc and psims may have substantial values even after the concentration gradients of Na and K across the cell membane are eliminated, provided that active transport mechanisms are still operative. Conversely, in the presence of approximately normal transmembrane ion concentration gradients, but when active transport mechanisms have been inhibited. psimc is reduced by 45% and psims is zero. These observations are consistent with a model of electrolyte transport in which psims and the normal transmembrane cation concentration gradients are established by rheogenic active transport of Na out of the cell. The psimc is generated both by rheogenic active Na transport and by cation concentration gradients which exist across the cell membrane. The Koefoed-Johnsen and Ussing model (Acta Physiol. Scand., 1958, vol. 42, p. 298) of electrolyte transport by epithelial cells does not adequately describe the electrical properties of ileum.

The effect of cyclical hormonal changes on erythrocyte electrolyte transport mechanisms

1986 ◽  
Vol 70 (3) ◽  
pp. 263-269 ◽  
Author(s):  
Eileen D. M. Gallery ◽  
Catherine Bean ◽  
Roslyn Grigg ◽  
Douglas M. Saunders
Keyword(s):  
Oral Contraceptive ◽  
Electrolyte Transport ◽  
Hormonal Changes ◽  
Transport Mechanisms ◽  
Time Intervals ◽  
Combined Oral Contraceptive ◽  
Normal Men ◽  
Androgenic Effect ◽  
86Rb Influx

1. Electrolyte transport characteristics were examined in erythrocytes from 13 normal men and from two groups of women: (i) taking combined oral contraceptive preparations (O/C, n = 10), and (ii) ovulatory women (non-O/C, n = 10) pre- and post-ovulation, at the same time intervals (days 7–10 and days 15–18) during a menstrual cycle. 2. With rubidium (86Rb+) used as a potassium analogue, co-transport (ouabain-resistant, fruse-mide-sensitive 86Rb+ influx) values were found to be lowest in non-O/C women (28 ± se 2.5 nmol h−1 10−9 cells) and highest in men (56 ± 5.7, P < 0.001), with results between the two in women taking O/C (42 ± 4.2, P < 0.05 vs men, P < 0.01 vs non-O/C). Passive 86Rb leak (frusemideand ouabain-resistant) was significantly lower in men (13 ± 1.6 nmol h−1 10−9 cells) than in both groups of women (non-O/C 29 ± 1.8, P < 0.001; O/C 25 ± 1.2, P < 0.001). There was no cyclical variation within either group of women. 3. Maximum ouabain binding (number of Na+,K+-ATPase units) was the same in all groups. Na+,K+-ATPase activity, as determined by ouabain-sensitive 86Rb influx, was the same in men and non-O/C groups, but was significantly suppressed in O/C compared with both men (P < 0.01) and non-O/C women (P < 0.05). 4. The differences found were not due to alterations in either progesterone or aldosterone, but could represent an androgenic effect in vivo of the 19-nortestosterone derivatives in combined oral contraceptive preparations.

Physical Properties of Isolated Perfused Renal Tubular Basement Membranes

1971 ◽  
Vol 29 ◽  
pp. 390-391
Author(s):  
Jared Grantham ◽  
Larry Welling
Keyword(s):  
Basement Membrane ◽  
Basement Membranes ◽  
Transport Mechanisms ◽  
Permeability Characteristics ◽  
Peritubular Capillaries ◽  
Strategic Location ◽  
Tubular Lumen ◽  
Glomerular Filtrate ◽  
Urine Formation ◽  
Renal Tubular

In the course of urine formation in mammalian kidneys over 90% of the glomerular filtrate moves from the tubular lumen into the peritubular capillaries by both active and passive transport mechanisms. In all of the morphologically distinct segments of the renal tubule, e.g. proximal tubule, loop of Henle and distal nephron, the tubular absorbate passes through a basement membrane which rests against the basilar surface of the epithelial cells. The basement membrane is in a strategic location to affect the geometry of the tubules and to influence the movement of tubular absorbate into the renal interstitium. In the present studies we have determined directly some of the mechanical and permeability characteristics of tubular basement membranes.

Alveolobronchiolar transport mechanisms

1973 ◽  
Vol 131 (1) ◽  
pp. 109-114 ◽  
Author(s):  
G. M. Green
Keyword(s):  
Transport Mechanisms
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