Rates of in vivo intestinal absorption of glycine and glycylglycine by rainbow trout (Salmo Gairdneri R.)

1981 ◽  
Vol 69 (3) ◽  
pp. 455-459 ◽  
Author(s):  
G. Bogé ◽  
A. Rigal ◽  
G. Pérès
1978 ◽  
Vol 74 (1) ◽  
pp. 227-237 ◽  
Author(s):  
J. Isaia ◽  
J. Maetz ◽  
G. P. Haywood

Using isolated heads perfused at constant pressure, at rates close to those occurring in vivo, the permeability of the gills of the trout Salmo gairdneri to a range of solutes was measured. Under epinephrine-free conditions, butanol and water showed similar high branchial permeability coefficients. Urea, inulin and dextrans (mol. wt 3000 and 20 000) were 7–12 times less permeant, and mannitol 60-70 times less permeant than water or butanol. Epinephrine, at 10(−6) M, greatly increased the permeability of the gills to the small hydrophilic molecules, water and urea, and to the lipophilic substance, butanol, but did not affect the penetration of the large hydrophilic solutes, mannitol, inulin and dextrans. In the presence of 10(−6) M propanolol, a beta-blocker, epinephrine had no effect on the permeation of any of the test substances except that the permeability to urea decreased somewhat. The results suggest that epinephrine increases the permeability of the membranes of the branchial cells but does not affect the permeation of substances that cross the gill walls by paracellular routes or via an intracellular ‘bulk-transport’ mechanism. Such an action would be expected to increase the branchial transfer of oxygen.


1986 ◽  
Vol 125 (1) ◽  
pp. 347-359 ◽  
Author(s):  
A. P. Farrell ◽  
C. L. Milligan

Myocardial intracellular pH was measured in a perfused rainbow trout, Salmo gairdneri, with DMO (5,5-dimethyl-2,4-oxazlidinedione), to test the hypothesis that catecholamines promote active regulation of myocardial pH in order to protect contractility during a respiratory acidosis comparable to that observed after exercise. Under control conditions (extracellular pH = 8.0; PCO2 = 2 Torr), myocardial pH was 7.53 +/− 0.01 (N = 5). Acidosis (extracellular pH = 7.45; PCO2 = 8.6 Torr) reduced contractility, mechanical efficiency and intracellular pH (7.25 +/− 0.04), but did not affect myocardial O2 consumption. The addition of 0.5 mumol l-1 adrenaline during extracellular acidosis prevented the loss of contractility, restored mechanical efficiency, but did not change intracellular pH significantly. Thus, adrenaline enabled cardiac contractility to recover, without intracellular pH regulation, possibly by modulation of sarcolemmal calcium changes. The absence of a myocardial acidosis after exercise in vivo is discussed with respect to possible intracellular pH regulation via lactate uptake and metabolism.


1981 ◽  
Vol 91 (1) ◽  
pp. 285-292 ◽  
Author(s):  
G. BOGÉ ◽  
A. RIGAL ◽  
G. PÉRES

The effects of 4 and 8 weeks fasting at 16 °C were studied in rainbow trout, Salmo gairdneri Richardson. After 4 and 8 weeks, the wet weights of the intestine of fasted animals are respectively 64% and 69% lower than those of fed animals. These effects especially concern the mucosal tissue. Glycine absorption (0.5 and 10 mm) was studied using an in vivo perfusion technique. After 4 weeks, the absolute amounts of 0.5 mm glycine absorbed by fasted and fed fish are similar. With 10 mm glycine, the absorption is slightly lower in fasted trout (−19%). After 8 weeks these differences are more marked, with glycine concentrations of 10 mm (−42%). Results expressed per 100 g body weight showed that these differences result partly from a weight gain of fed trout. Absorption expressed in terms of weight of dry intestine is higher in 4 and 8 weeks fasted animals, principally for the lower amino acid concentration (+61% and +111%). Larger differences were apparent when the absorptions were expressed in terms of dry weight of mucosal tissue (+122% and +225%).


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