ISSN:
1432-1424
Source:
Springer Online Journal Archives 1860-2000
Topics:
Biology
,
Chemistry and Pharmacology
Notes:
Summary Oxygen consumption, glycogen content, transmural potential difference (PD), and short-circuit current (SCC) were measured in fresh turtle hemibladder sacs and in matching sacs depleted by 18 hr of incubation in aerated, substrate-free Ringer's solution. Percent of original values after depletion were: oxygen consumption, 61%; glycogen content, 36%; PD, 28%; SCC, 19%. PD and SCC responded to addition of substrate (5.5mm glucose plus 2mm pyruvate) by a lag period of approximately 2 hr followed by progressive increases lasting for many hours. Other experiments utilized split bladders. The epithelium and adhering connective tissue (mucosal fraction) were separated from the underlying smooth muscle and connective tissue (serosal fraction) and the oxygen consumption and glycogen content of slices of the two fractions determined. Mucosal oxygen consumption declined to 48% of the original value during depletion while serosal oxygen consumption (initially much lower than mucosal) was well-maintained at 95% of the original value. Substantial net synthesis of glycogen took place in both fractions of depleted bladders after addition of substrate. The ratio of moles of oxygen consumed to moles of glucose (from glycogen) disappearing during the 18-hr depletion period was approximately 5.5 for serosal tissue and within the range 30 to 61 for mucosal tissue. The mucosal ratio was incompatible with the utilization of glycogen as the major endogenous substrate during depletion under aerobic conditions. It is suggested that the oxidation of lipid supports most of the endogenous metabolism in the mucosal tissue of the turtle bladder.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF01868103
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