Quantitative Untersuchungen �ber die Wirkung von Choriongonadotropin auf m�nnliche Laubfr�sche

Wohlzogen, F. X.; Halama, Anna

doi:10.1007/bf00637822

Cited by 3 publications

(5 citation statements)

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“…It is noticeable that the slopes of the two curves for the response of B. bufo differ from one another. Yet Wohlzogen (1954), using this species, found the same slope for both types of gonadotrophin. A possible explanation may be that the two lots of toads receiving PMS were treated at different times of year; but there is at present no evidence on seasonal variation in the response to this type of gonadotrophin.…”

Section: Resultsmentioning

confidence: 51%

“…Both the present species show variation in the ED50 for their response to UP and PMS, which can be accounted for by the difference in the actual amount of each gonadotrophin defined as equivalent to an International Unit. Wohlzogen (1954) found corresponding responses in toads when 3.5 times as many International Units of PMS as of UP were used.…”

Section: Resultsmentioning

confidence: 88%

“…Wohlzogen (1954) found corresponding responses in toads when 3.5 times as many International Units of PMS as of UP were used.…”

mentioning

confidence: 88%

“…It is possible that the greater variation in his later findings may have been due to the much greater variation in the size of B. regularis males, which may be associated with greater variability in response: in B. bufo, it has been shown by Wohlzogen (1954) that light toads are more sensitive than heavy ones. This latter fact may also account for the present slope of 4.0 found for the response of the latter species to UP, which differs markedly from that originally found (Frazer and Wohlzogen, 1951).…”

mentioning

confidence: 97%

“…While the work on treefrogs was taking place, Wohlzogen and Halama (1951) were performing a similar investigation with UP in Vienna, the only difference being that their treefrogs came from Eastern Austria. Comparison between the two sets of work (Frazer and Wohlzogen, 1953) showed that the slope of the regression line could be taken as common to both investigations with a value of 3.88, although there was a distinct variation between them as far as the ED50 was concerned: the Austrian treefrogs were the more sensitive.…”

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confidence: 99%

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The Sperm‐shedding Response of Male Toads and Treefrogs After the Injection of Two Types of Gonadotrophin

Frazer

1956

British Journal of Pharmacology and Chemotherapy

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Injection of gonadotrophin into the male British toad (Bufo bufo) is followed by the shedding of sperm, the response being of the normal quantal type (Frazer and Wohlzogen, 1951). The doseresponse curve of the toad has now been investigated more fully with chorionic gonadotrophin, which is of the luteinizing type. At the same time the response to pregnant mare's serum gonadotrophin (of the follicle-stimulating type) was also studied to see if the two curves differed greatly in either ED50 or slope. The response of the treefrog (Hyla arborea) was also investigated, since it seemed possible that this smaller species might respond to smaller doses, and so be more suitable for the estimation of relatively small amounts of gonadotrophin.The effect of chorionic gonadotrophin on the toad was also examined to see whether it altered at different times of the year under relatively standard laboratory conditions. The effect of alteration in environmental temperature was also studied. With this knowledge, the gonadotrophin excretion during pregnancy was followed in 5 cases, using a technique already developed (Frazer and Wohlzogen, 1951). METHODS Experimental Animals.-Toads and treefrogs were kept in an animal house at approximately 21.5°C. The experiments were normally conducted in a laboratory kept at about 20°C. The conditions during the temperature experiments are described later. In the seasonal work, the batches of toads were taken as far as possible through the summer at 6-week intervals, being used exactly one week after they had been obtained from the dealer. The interval between receipt and use was left to avoid using toads which might already have been shedding sperms. The isolation of the males from females for a week is normally sufficient to achieve this object, even when, on receipt from the breeding ponds, the cloacal urine of the males is swarming with spermatozoa. They were kept during this week in large cages containing moss and water, and fed on maggots and flies.The toads were from the south of England, and the treefrogs were of sp. typica from N. Italy.Gonadotrophins.-International Standard gonadotrophins were used for the dose-response curves, the luteinizing type from human pregnancy urine (UP) and the follicle-stimulating type from pregnant mares' serum (PMS); for the experiments on temperature, a crystalline preparation was made from pregnancy urine by the method of Claesson, Hogberg, Rosenberg, and Westman (1948). The gonadotrophin was always dissolved in distilled water; the injection volume was 1 ml.When gonadotrophins were being estimated in pregnancy urine, the urine was filtered and injected directly. Dilutions of urine were also used, and gonadotrophin concentrates were made from samples when necessary, either because of the toxicity of the urine or because there was only a low level of gonadotrophin in it. For this purpose, the method of Scott (1940) was used, modified by the use of Universal Indicator (B.D.H.). The technique of Frazer and Wohlzogen (1951) was used for gonadotrophin estim...

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Section: Resultsmentioning

confidence: 51%

Section: Resultsmentioning

confidence: 88%

“…Wohlzogen (1954) found corresponding responses in toads when 3.5 times as many International Units of PMS as of UP were used.…”

mentioning

confidence: 88%

mentioning

confidence: 97%

mentioning

confidence: 99%