Dicamptodon is the single, extant genus of the
ambystomatid subfamily Dicamptodontinae. Two species, D.
ensatus (Eschscholtz) and D. copei Nussbaum are recognized.
D. ensatus is found in the forested, mountain regions of
northwestern California and western Oregon, in the Willapa
Hills and Cascade Mountains of Washington, in extreme
southwestern British...
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...
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...
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...
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...
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...
This study deals with the patterns of development and distribution
of connective tissue fibers in the placentae and adnexa of the golden
hamster (Mesocricetus auratus Waterhouse). The placentae and
adnexa representing all days of gestation from six to term were
stained for the presence of collagen, reticulin, and elastin. Additionally,...
Female Sprague-Dawley rats (220-240 g) were ovariectomized
and seven days later were either treated as controls or received a
single injection of either 0.1 μg, 100 μg, or 2 mg of estradiol-17β dissolved in 0.1 cc propylene glycol. These rats were autopsied
either 1, 3, 6, 24, 48, or 72...
This study deals with the autoradiographic analysis, using a
DNA precursor (tritiated thymidine), of the trophoblastic giant cells
in the placentae of the golden hamster (Mesocricetus auratus Waterhouse),
beginning with the sixth day of gestation and extending to term
on day sixteen. Both the percent of labelled cells in the...