scholarly journals Calling behavior of male South African clawed frogs (Xenopus laevis) is affected by 17α-ethinyl estradiol

2011 ◽  
Vol 2 ◽  
Author(s):  
Kloas Werner
1969 ◽  
Vol 43 (1) ◽  
pp. 47-53 ◽  
Author(s):  
M. R. REDSHAW ◽  
B. K. FOLLETT ◽  
T. J. NICHOLLS

SUMMARY A comparison has been made between the effects of oestradiol-17β, oestrone, oestriol, progesterone, testosterone and cortisone on the plasma concentration of proteins and lipids in the South African clawed toad, Xenopus laevis Daudin. No major changes in the parameters studied were found with the non-oestrogenic steroids; only the three oestrogens induced the appearance in the plasma of a calcium-binding phospholipoprotein and esterified lipids associated with yolk formation. These results support the hypothesis that the oestrogens alone cause the vitellogenic response in oviparous vertebrates. Dose—response curves for oestradiol-17β, oestrone and oestriol were established for the effects on plasma protein, calcium, protein-bound phosphorus, phospholipid, lipid and cholesterol. The curves obtained were log.-linear over the range of doses employed (oestradiol-17β, 1–50 μg./day; oestrone, 4–100 μg./day; oestriol, 20–500 μg./day) with the exception of the cholesterol response to oestradiol. The relative potencies of the three oestrogens were compared for each of the plasma components measured. Oestradiol-17β was the most potent, being 3·9 times more active than oestrone and 13·7 times more active than oestriol.


1979 ◽  
Vol 80 (3) ◽  
pp. 407-408 ◽  
Author(s):  
B. SHAPIRO ◽  
M. SHEPPARD ◽  
S. KRONHEIM ◽  
B. L. PIMSTONE

Immunoreactive somatostatin is present in the brain, gut and pancreas of the South African clawed toad, but is absent from the skin, a rich source of many other brain–gut peptides.


1995 ◽  
Vol 198 (12) ◽  
pp. 2465-2475 ◽  
Author(s):  
D Hastings ◽  
W Burggren

Well-developed larval Xenopus laevis (NF stages 58­66) are oxygen regulators, at least during mild hypoxia. When and how they change from oxygen conformers (the presumed condition of the fertilized egg) to oxygen regulators is unknown. Also unknown is how anaerobic metabolic capabilities change during development, especially in response to acute hypoxia, and to what extent, if any, anaerobiosis is used to supplement aerobic metabolism. Consequently, we have investigated resting rates of oxygen consumption (M.O2) and concentrations of whole-body lactate (lactic acid) during development in normoxia and in response to acute hypoxia in Xenopus laevis. M.O2 increased in an episodic, non-linear fashion during development. Resting, normoxic M.O2 increased about tenfold (to approximately 0.20 µmol g-1 h-1) between NF stages 1­39 and 40­44, and then another tenfold between NF stages 45­48 and 49­51 (to approximately 2.0 µmol g-1 h-1), remaining at about 2 µmol g-1 h-1 for the remainder of larval development. M.O2 reached its highest level in newly metamorphosed frogs (nearly 4 µmol g-1 h-1), before decreasing to about 1.0 µmol g-1 h-1 in large adults. X. laevis embryos and larvae up to NF stage 54­57 were oxygen conformers when exposed to variable levels of acute hypoxia. The only exception was NF stage 45­48 (external gills present yet body mass still very small), which showed some capability of oxygen regulation. All larvae older than stage 54­57 and adults were oxygen regulators and had the lowest values of Pcrit (the oxygen partial pressure at which M.O2 begins to decline). Whole-body lactate concentration in normoxia was about 1 µmol g-1 for all larval groups, rising to about 12 µmol g-1 in adults. Concentrations of lactic acid in NF stages 1­51 were unaffected by even severe ambient hypoxia. However, whole-body lactate levels in NF stages 52­66 increased in response to severe hypoxia, indicating that some anaerobic metabolism was being used to supplement diminishing aerobic metabolism. The largest increases in concentration of lactate occurred in late larvae and adults.


1932 ◽  
Vol 9 (3) ◽  
pp. 233-237
Author(s):  
D. EPSTEIN ◽  
J.W. C. GUNN ◽  
E. EPSTEIN ◽  
G. RIMER

1. Adrenal bodies have been shown to be present on the anterior or ventral surface of the kidneys of Xenopus. Extracts of this region of the kidney contain a sympathomimetic substance, probably adrenaline. 2. Active preparations are best obtained by extracting freshly excised kidneys with normal saline solution. The extracts should be used immediately. 3. Amphibian tissues appear to react more sensitively than mammalian tissues towards the extracts.


Development ◽  
1969 ◽  
Vol 22 (2) ◽  
pp. 265-277
Author(s):  
Margaret J. Manning ◽  
John D. Horton

Before embarking on a study of the lymphoid system of an amphibian larva, it is necessary to realize that lymphoid tissue may occur in many organs of the body and that in all immature vertebrates and in adult poikilotherms separation of lymphoid tissue from myeloid tissue is incomplete (Yoffey, 1960). Jordan (1938) reviewed the early work on the haemopoietic tissues of Amphibia. Cooper (1967 a, b) and Baculi & Cooper (1967) made a thorough investigation of the lymphomyeloid and lymphoepithelial organs of the bullfrog, Rana catesbeiana, in the branchial region of the larva and in the ventral neck region of the adult. In the larva they found three pairs of ventral cavity bodies and one pair of lymph glands; in the adult, propericardial bodies, procoracoid bodies, epithelial bodies and jugular bodies were present. Cooper (1967a) reviewed the literature on these organs and discussed their nomenclature.


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