Male Toads in Pregnancy Tests

Frazer, J. F. D.; Wohlzogen, F. X.

doi:10.1016/s0140-6736(49)90036-7

Cited by 3 publications

(2 citation statements)

References 2 publications

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“…This relative unimportance of the maternal pituitary for foetal growth is in agreement with the results of Cotes & Young [1951], who were unable to find growth hormone in the urine of pregnant women or the blood of a pregnant goat. On the other hand, Watts [1935] demon¬ strated increases in foetal weights after injections of impure preparations of growth hormone, a finding which was not confirmed by Frazer, Huggett & Wohlzogen [1949]. In two rats injected for a different purpose with 2-5 mg ( = approx.…”

Section: Discussionmentioning

confidence: 98%

Some Dietary and Hormonal Effects on Maternal, Foetal and Placental Weights in the Rat

Campbell¹,

Innes²,

Kosterlitz³

1953

J Endocrinol

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A negative correlation was found between the mean weight of an individual placenta and the number in a litter. Within the range examined and with the methods employed, no definite correlation between the mean weight of an individual foetus and litter size was established.Reduction of the food intake to one-half or one-third during the last 6 days of pregnancy did not result in a decrease in the number and weight of foetuses and placentae. This was apparently brought about by drawing on the maternal reserves laid down during the first 14 days of pregnancy. Absence of protein from the diet during the last 6 days resulted in a very moderate decrease in foetal and placental weights.Absence of the maternal adrenals or pituitary had no influence on foetal and placental weights. The decrease in maternal body weight after hypophysectomy was solely due to loss of appetite and could be prevented by giving the rats adequate amounts of food by stomach tube.The increase in body weight during the first 14 days of pregnancy was maintained after removal of the foetuses as long as the placentae survived. The placentae also had a favourable effect on the maternal body weight in the absence of the foetuses, when the ovaries or adrenals or the pituitary or the pituitary and ovaries were removed, but not when both ovaries and adrenals were absent. The placental factor responsible for this effect appears to act through the ovaries or adrenals.The increase in the weight of the ovaries during pregnancy was not affected by removal of the foetuses, foetuses and pituitary, or foetuses and adrenals. The adrenals of pregnant hypophysectomized rats were not heavier than those of non-pregnant hypophysectomized rats.In the preceding paper [Campbell, Innes & Kosterlitz, 1953] pregnant rats were subjected to a number of experimental procedures in an attempt to determine the factors responsible for the formation of excess ribonucleic acid in the maternal hver. In most of these experiments records were taken of maternal, foetal and placental weights. An analysis of these findings is made in the present paper. MATERIAL AND METHODSThese were the same as the ones used in the preceding paper [Campbell et al. 1953]. RESULTSBefore it was possible to analyse the effects of diet on the foetal and placental weights, it was necessary to examine whether a correlation existed between the number of foetuses in a htter and the mean weight of an individual foetus or placentae. Within the range observed, and with the methods employed, no correlation was found between the number and weights of foetuses ; the validity of this finding will be considered later. On the other hand, a significant negative correlation was found between the weights and numbers of the placentae (Fig.

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Section: Discussionmentioning

confidence: 98%

Some Dietary and Hormonal Effects on Maternal, Foetal and Placental Weights in the Rat

Campbell¹,

Innes²,

Kosterlitz³

1953

J Endocrinol

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“…the dose which is effective in 50 % of the experimental animals) was around 8 i.u. (Frazer & Wohlzogen, 1949).…”

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confidence: 99%

The estimation of chorionic gonadotrophin, using the male british toad Bufo bufo

Frazer¹,

Wohlzogen²

1951

The Journal of Physiology

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Further Experiences with the Male-toad Pregnancy Test Using European Species

Haines¹,

Ferreira²,

Law³

et al. 1954

Journal of Clinical Pathology

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The satisfactory reports on the Galli Mainini male toad test for pregnancy which have been published from nearly every part of the world (Cowie, 1948 ; Bhaduri, 1951) show that the test can be performed on species of toads or frogs indigenous to the district where the laboratory is situated. In England and Europe the toads Bufo bufo (syn. B. vulgaris) and B. calamita and the frog Rana esculenta are used for the test. Favourable results with these species have been reported by Hinglais and Hinglais (1948), Haines and Ferreira (1949), Klopper and Frank (1949), Frazer andWohlzogen (1949), andBach, Szmuk, Robert, andKlinger (1949). In a later paper Frazer and Wohlzogen (1951) described a method for estimating urinary gonadotrophin using B. bufo. Modifications of the Earlier TechniqueThe principle and the technique of the test which have already been described for a South American species (Haines, 1948) are readily adapted to European species and the technical details of modifications in procedure which we found necessary for the new species have been described by Law (1949).The toads available weighed only 15-25 g. and the volume of urine injected was reduced to 2 ml., i.e. 1 ml. per 10 g. body weight. Because there was an injection mortality of up to 40% a modified purification method was tried (Scott, 1940) Reading of the TestThe end-point is taken as the appearance of spermatozoa in a specimen of toad's urine usually collected from the cloaca. Spermatozoa may be found in less than one hour after injection. Our tests were read at the end of three hours-or four if negative at three. Under circumstances where a weak positive response was to be expected (see below) readings were taken at five and six hours. A weak positive is denoted by a delayed response of the test animal and by the presence of relatively few sperms per low-power field. Increasing numbers of sperms may be found at the end of the fourth and fifth hours when only two or three per field were found at the end of the third hour. In our experience few sperms per field, in the absence of a delayed response, indicate exhaustion of the test animal. The urine of positive reactors was found clear of spermatozoa within two days of the injection. All animals used in the series were tested (and found negative) before a test was begun.

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Male Toads in Pregnancy Tests

Cited by 3 publications

References 2 publications

Some Dietary and Hormonal Effects on Maternal, Foetal and Placental Weights in the Rat

Some Dietary and Hormonal Effects on Maternal, Foetal and Placental Weights in the Rat

The estimation of chorionic gonadotrophin, using the male british toad Bufo bufo

Further Experiences with the Male-toad Pregnancy Test Using European Species

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