Stimulation of the Sodium Pump in Frog Bladder by Oxytocin

Nature ◽  
1967 ◽  
Vol 215 (5104) ◽  
pp. 992-993 ◽  
Author(s):  
K. JANÁČEK ◽  
R. RYBOVÁ
Keyword(s):  
Hypertension ◽  
1995 ◽  
Vol 26 (1) ◽  
pp. 177-185 ◽  
Author(s):  
Juliana Redondo ◽  
Concepción Peiró ◽  
Leocadio Rodríguez-Mañas ◽  
Mercedes Salaices ◽  
Jesús Marín ◽  
...  

1997 ◽  
Vol 200 (22) ◽  
pp. 2881-2892 ◽  
Author(s):  
P Leong ◽  
D Manahan

Early stages of animal development have high mass-specific rates of metabolism. The biochemical processes that establish metabolic rate and how these processes change during development are not understood. In this study, changes in Na+/K+-ATPase activity (the sodium pump) and rate of oxygen consumption were measured during embryonic and early larval development for two species of sea urchin, Strongylocentrotus purpuratus and Lytechinus pictus. Total (in vitro) Na+/K+-ATPase activity increased during development and could potentially account for up to 77 % of larval oxygen consumption in Strongylocentrotus purpuratus (pluteus stage) and 80 % in Lytechinus pictus (prism stage). The critical issue was addressed of what percentage of total enzyme activity is physiologically active in living embryos and larvae and thus what percentage of metabolism is established by the activity of the sodium pump during development. Early developmental stages of sea urchins are ideal for understanding the in vivo metabolic importance of Na+/K+-ATPase because of their small size and high permeability to radioactive tracers (86Rb+) added to sea water. A comparison of total and in vivo Na+/K+-ATPase activities revealed that approximately half of the total activity was utilized in vivo. The remainder represented a functionally active reserve that was subject to regulation, as verified by stimulation of in vivo Na+/K+-ATPase activity in the presence of the ionophore monensin. In the presence of monensin, in vivo Na+/K+-ATPase activities in embryos of S. purpuratus increased to 94 % of the maximum enzyme activity measured in vitro. Stimulation of in vivo Na+/K+-ATPase activity was also observed in the presence of dissolved alanine, presumably due to the requirement to remove the additional intracellular Na+ that was cotransported with alanine from sea water. The metabolic cost of maintaining the ionic balance was found to be high, with this process alone accounting for 40 % of the metabolic rate of sea urchin larvae (based on the measured fraction of total Na+/K+-ATPase that is physiologically active in larvae of S. purpuratus). Ontogenetic changes in pump activity and environmentally induced regulation of reserve Na+/K+-ATPase activity are important factors that determine a major proportion of the metabolic costs of sea urchin development.


2002 ◽  
Vol 48 (10) ◽  
pp. 1720-1730 ◽  
Author(s):  
M Adnan El-Masri ◽  
Barbara J Clark ◽  
Hassan M Qazzaz ◽  
Roland Valdes

Abstract Background: Ouabain-like factor (OLF) and its newly discovered reduced species, dihydroouabain-like factor (Dh-OLF), are mammalian cardenolides whose structural and functional characteristics are similar to the plant-derived compounds ouabain and dihydroouabain. These endogenous compounds are believed to be produced by the adrenals and to constitute part of an hormonal axis that may regulate the catalytic activity of the α-subunit of Na+,K+-ATPase. We developed antibodies sufficiently specific to distinguish between OLF and Dh-OLF, and in this study demonstrate the selective secretion of OLF and Dh-OLF from human H295R-1 adrenocortical cells in culture. Methods: We used reversed-phase HPLC, inhibition of Na+,K+-ATPase catalytic activity, and two enzyme immunoassays developed with antibodies specific to ouabain and dihydroouabain to purify and characterize the secretion of these two compounds by human adrenal cells in culture. Purified antisera had high titers (1 × 106 for ouabain and 8 ×105 for dihydroouabain) and were specific to their corresponding antigens. Results: Human H295R-1 cells grown in serum-free medium secreted 0.18 ± 0.03 pmol of OLF and 0.39 ± 0.04 pmol of Dh-OLF per 106 cells in 24 h. Both OLF and Dh-OLF inhibited the ouabain-sensitive catalytic activity of the sodium pump (0.03 μmol/L OLF inhibited 29% of the catalytic activity; 0.07 μmol/L Dh-OLF inhibited 17%). Stimulation of the cell culture by dibutryl cAMP increased the secretion of Dh-OLF 50% over control (unstimulated), whereas the secretion of OLF did not increase significantly. Conclusions: OLF and Dh-OLF are secreted by human adrenal cells, and antibodies specific to these two compounds can be developed, using the plant-derived counterparts as antigens. The secretion of Dh-OLF is responsive to a cAMP-dependent stimulation mechanism, whereas OLF is not. Our data suggest that either the secretory or biosynthetic pathways for production of these two compounds by human adrenal cells may have different control mechanisms or that they may be linked via a precursor–product relationship.


2003 ◽  
Vol 549 (3) ◽  
pp. 787-800 ◽  
Author(s):  
Ralph Nelson ◽  
Anna M. Bender ◽  
Victoria P. Connaughton

1972 ◽  
Vol 50 (4) ◽  
pp. 378-380 ◽  
Author(s):  
Deepak Bose ◽  
Ian R. Innes

Ouabain or replacement of NaCl by LiCl abolishes the relaxation due to addition of KCl to sodium-rich cat carotid artery strips kept in a K+-free medium. Neither treatment antagonizes the relaxation due to β-adrenoceptor stimulation by l-isoprenaline. Unlike KCl-induced relaxation, the relaxation induced by l-isoprenaline is not due to stimulation of an electrogenic sodium pump.


1983 ◽  
Vol 245 (3) ◽  
pp. G364-G368 ◽  
Author(s):  
D. J. Stewart ◽  
D. J. Pon ◽  
A. K. Sen

Oxygen consumption of slices of rat submandibular gland was monitored with an oxygen electrode method. Carbachol stimulated an immediate increase in tissue respiration that was inhibitable by ouabain. The stimulation required the presence of calcium in the incubation medium and was blocked by atropine. The calcium ionophore A23187 also stimulated ouabain-sensitive oxygen consumption in the tissue slices. The results show that the mechanism using the extra energy during cholinergic stimulation is the sodium pump. Amiloride at a 1, 10, or 100 microM concentration had no effect on stimulation of ouabain-sensitive respiration by carbachol. Since amiloride, which is known to block the sodium reabsorption process in the ductal segment, has no effect on the stimulation, the increased sodium pump activity is probably located in the acinar region and is associated with the primary fluid secretion process.


Nature ◽  
1968 ◽  
Vol 220 (5173) ◽  
pp. 1236-1239 ◽  
Author(s):  
HEYWOOD ERIC BECKER ◽  
TIMOTHY H. GOLDSMITH

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