In freshwater the crayfish, Pacifasticus leniusculus, maintains
sodium balance by absorbing sodium against a large concentration
gradient. The site of uptake is the gills. The rate of uptake is
regulated and can be increased by depleting the animals of sodium
Neither the mechanism of sodium transport or the regulatory mechanism...
Temperature effects on osmoregulation were studied in larval
Ambystoma gracile. There was a pronounced effect on the osmotic
uptake of water through the skin. The rates at 5°C, 15°C and 25°C
were respectively 0.03 ml/hr., 0.1 ml/hr. and 0.2 ml/hr. for a
10g animal. The Q₁₀'s for these changes in...
By salt depleting the animals or by injecting them with
aldosterone, I was able to increase the active transport of sodium
across the isolated skin. The potential difference was increased
by 37% and 43% respectively and the net sodium flux by 69% and
62%. Exposure of frogs to 50 mM...
Aspects of hydromineral balance in the stenohaline fresh-water
catfish, Ictalurus nebulosus (Le Sueur) were studied at 10° and 20°C.
Temperature did not affect water content significantly. Water content
was 78 ml/100 g body weight, 32% of which is in muscle and 49% in
the skeleton and associated connective tissue. The...
Chloride is actively transported across the skin of
the intact
leopard frog, Rana pipiens.
The influx and efflux in 0.2 mM NaC1
are 0.67 and 0. 72 μeq/10 g-hr, respectively.
The renal efflux of
chloride is 0.02 μeq/10 g-h .
The transepithelial potential differences (TEP) range from -1 to +32...
Calcium concentration and its regulation was examined in
tissues of larval Rana catesbiana. Considerable variability was
found in tissue calcium that could not be explained by stage of development.
A seasonal effect was observed, with plasma calcium decreasing
and muscle calcium increasing during winter. Total plasma
calcium concentration reflects, within...
Earthworms are capable of osmotic and ionic regulation while
living in a dilute balanced salt solution. When transferred from soil
to pond-water (PW) their body weight increases by 15 percent due to
a net uptake of water.
This results in an initial dilution of the
coelomic fluid (CF).
Subsequently, Na...