pH-regulatory mechanisms in in vitro perfused rectal gland tubules of Squalus acanthias

1998 ◽  
Vol 436 (2) ◽  
pp. 248-254 ◽  
Author(s):  
M. Bleich ◽  
R. Warth ◽  
I. Thiele ◽  
R. Greger
Keyword(s):  
Squalus Acanthias ◽  
Regulatory Mechanisms ◽  
Rectal Gland

Mechanism of active chloride secretion by shark rectal gland: role of Na-K-ATPase in chloride transport

1977 ◽  
Vol 233 (4) ◽  
pp. F298-F306 ◽  
Author(s):  
P. Silva ◽  
J. Stoff ◽  
M. Field ◽  
L. Fine ◽  
J. N. Forrest ◽  
...  
Keyword(s):  
Chloride Transport ◽  
Sodium Concentration ◽  
Chloride Secretion ◽  
Squalus Acanthias ◽  
Rectal Gland ◽  
Tentative Hypothesis ◽  
Shark Rectal Gland ◽  
Electrochemical Equilibrium

The isolated rectal gland of Squalus acanthias was stimulated to secrete chloride against an electrical and a chemical gradient when perfused in vitro by theophylline and/or dibutyryl cyclic AMP. Chloride secretion was depressed by ouabain which inhibits Na-K-ATPase. Thiocyanate and furosemide also inhibited chloride secretion but ethoxzolamide, a carbonic anhydrase inhibitor, did not. Chloride transport was highly dependent on sodium concentration in the perfusate. The intracellular concentration of chloride averaged 70-80 meq/liter in intact glands, exceeding the level expected at electrochemical equilibrium and suggesting active transport of chloride into the cell. These features suggest a tentative hypothesis for chloride secretion by the rectal gland in which the uphill transport of chloride into the cytoplasm is coupled through a membrane carrier to the downhill movement of sodium along its electrochemical gradient. The latter is maintained by the Na-K-ATPase pump while chloride is extruded into the duct by electrical forces.

Regulation of the Na + 2Cl - K + cotransporter in in vitro perfused rectal gland tubules of Squalus acanthias

1998 ◽  
Vol 436 (4) ◽  
pp. 521-528 ◽  
Author(s):  
R. Warth ◽  
M. Bleich ◽  
I. Thiele ◽  
F. Lang ◽  
R. Greger
Keyword(s):  
Squalus Acanthias ◽  
Rectal Gland

Osmotically Induced Conductance and Capacitance Changes in in vitro Perfused Rectal Gland Tubules of Squalus acanthias

1998 ◽  
Vol 21 (5) ◽  
pp. 317-324 ◽  
Author(s):  
I. Thiele ◽  
R. Warth ◽  
M. Bleich ◽  
S. Waldegger ◽  
F. Lang ◽  
...  
Keyword(s):  
Squalus Acanthias ◽  
Rectal Gland

The effect of organotin compounds on chloride secretion by the in vitro perfused rectal gland of Squalus acanthias

1989 ◽  
Vol 100 (2) ◽  
pp. 307-314 ◽  
Author(s):  
Richard Solomon ◽  
Stephanie Lear ◽  
Robert Cohen ◽  
Kate Spokes ◽  
Patricio Silva ◽  
...  
Keyword(s):  
Chloride Secretion ◽  
Squalus Acanthias ◽  
Organotin Compounds ◽  
Rectal Gland

CONTRIBUTION TO THE EXISTENCE OF REGULATORY MECHANISMS AT THE ADRENAL LEVEL

1972 ◽  
Vol 70 (4) ◽  
pp. 741-757
Author(s):  
Otto Linèt
Keyword(s):  
Orotic Acid ◽  
Adrenal Glands ◽  
Actinomycin D ◽  
Delay Period ◽  
Regulatory Mechanisms ◽  
Leucine Incorporation ◽  
Total Period ◽  
Free Media

ABSTRACT Rat adrenal glands atrophied by the administration of cortisol acetate in vivo were used as a model for the study of early metabolic processes occurring in vitro. Atrophied adrenals incubated in the presence of 14C-leucine incorporated subnormal quantities of this amino acid per mg of protein for the first 120 min. When the incubation lasted for a total period of 180 or 240 min a supranormal rise in the 14C-leucine incorporation was observed. Similar changes occurred with some delay with regard to corticosterone production as expressed per 100 mg of tissue. No differences in 14C-leucine incorporation were observed between the control and atrophied adrenals in vivo. Homogenates from atrophied glands incorporated 14C-leucine to a greater extent than the control homogenates. The in vitro incorporation of 14C-orotic acid into the RNA was also higher in atrophied adrenals. The in vitro use of actinomycin D, cycloheximide and amphenone indicated that corticosterone production depended on the incorporation of 14C-leucine. The addition of cortisol to the incubation media markedly decreased the enhancement of 14C-lysine incorporation into the protein of atrophied adrenals. These, as well as additional results suggest rebound phenomena: once atrophic adrenals are transferred to cortisol-free media, reparative processes begin after a delay period. Such phenomena seem to be mediated by regulatory mechanisms at the adrenal level.

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