Quantitative data on the inhibition of œstrus by testosterone, progesterone, and certain other compounds

Robson, J. M.

doi:10.1113/jphysiol.1938.sp003609

Cited by 43 publications

(5 citation statements)

References 4 publications

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“…A further relationship between the suprarenal cortex and estrogenic activity is suggested by the findings that 17-hydroxycorticosteroids, which are practically synonymous with cortisol, simulate dehydroepiandrosterone in their quantitative excretion, either in relation to a menstrual cycle3° or during administration of estradiol.31 But, in contradistinction to cortisol, dehydroepiandrosterone possesses estrogenic tendencies . [11][12][13][14][15][16][17][18][19][20][21] With cholesterol metabolism and estrogenic hormones playing such a prominent role in the present day research concerning atherosclerosis, it seems proper to reproduce here the structural formulas of cholesterol and estrone, flanking the formula of dehydroepiandrosterone to facilitate comparison ( fig. 1).…”

Section: -Ketosteroidsmentioning

confidence: 99%

17-Ketosteroids and Arteriosclerosis*t

Kask¹

1959

Angiology

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It seems unlikely that major and decisive advances in our understanding, prevention, and treatment of arteriosclerotic diseases will be made if concentration of research on dietary lipids and their effects continues. It is hard to see how the internal regulators, namely, enzymes and hormones, can be disregarded or given only a behind-the-scene place. They govern also the metabolism of lipids. It is therefore not too early that some attention has, more recently, been paid to enzymology in arteriosclerosis, both in respect to etiologyl-4 and treatment, 6. s and that the enzymatic constituents nicotinic acid and pyridoxin are becoming popular.The short remarks in the following paragraph will point out the inadequacies of the dietary lipid theories, since they are otherwise seldom, if ever, mentioned.(1) Relative freedom from coronary heart disease in certain populations, allegedly due to their low intake of fats, may be accompanied by a high incidence and a relatively severe degree of cerebral and aortic atherosclerosis in the same populations.'-9 In older age groups the race differences may be slight also in the case of coronary atherosclerosis.9 (2) The results of animal experimentation with lipids are inconclusive regarding man. This is self explanatory and repeatedly demonstrated in research. Concerning the widely used experimentation with rabbits it has been shownlo that the gradual exsanguination caused by the frequent withdrawals of blood samples for cholesterol determination is in itself sufficient to obtain hypercholesterolemia and some degree of atherosclerosis in the animals, without lipid feedings.(3) The definite sex difference in the severity of atherosclerosis before the age of 50 can hardly be explained by the dietary theories, particularly since a careful studyll has failed to detect any corresponding differences in the diet of the two sexes. (4) The observed relative freedom of at least some American Indian tribes from atherosclerosis in spite of their enjoyment of the same type of diet as other Americans cannot be reconciled with nutritional explanations. Testicular hormones have also been thought to aggravate or accelerate the development of atherosclerosis. Although this thought may seem attractive in younger age groups it seems quite alien in older people who suffer most from atherosclerosis. After the age of 50 there is a progressive and accelerated increase of atherosclerosis in both sexes, while at the same time the secretion of testicular hormones decreases progressively, even in men who did produce them well before. Also, women, completely lacking the testicular hormones, still develop atherosclerosis, at times even at an early age and in possession of apparently normally functioning ovaries. Although the rich supply of the ovarian estrogenic hormones in young women may explain their relative freedom from atherosclerosis, such an explanation would remain confined to the female sex, and, in the case of at least the Negro race, would not be valid even for this sex on the basis of recent repo...

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Section: -Ketosteroidsmentioning

confidence: 99%

17-Ketosteroids and Arteriosclerosis*t

Kask¹

1959

Angiology

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“…Thus, not only may there be species differences, but in addition, substances having one property of progesterone may not have them all. This is well exemplified by testosterone, which Robson (1938) found to be a more powerful hormone than progesterone in suppressing oestrus in the mouse, but to be ineffective in maintaining pregnancy in the same animal when spayed. Courrier (1935) proposed that the assay of progesterone should depend upon implantation of ova or maintenance of pregnancy in the spayed animal; he devised a technique for detecting the level of progesterone necessary for 152 THE PREGNANT SPAYED RAT implantation of ova in the spayed rabbit.…”

Section: Discussionmentioning

confidence: 99%

The effect of steroids on the maintenance of pregnancy in the spayed rat*

Alexander¹,

Frazer²,

Lee³

1955

The Journal of Physiology

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Marshall & Jolly (1905 a, b) were the first to report that removal of the ovaries from the rat early in pregnancy was followed by foetal loss, although the duration of pregnancy when the rats were spayed is unknown. Subsequently, a number of workers have carried out similar experiments at different stages of pregnancy with or without removal of some of the foetuses (Selye, Collip & Thomson, 1935;Haterius, 1936;McKeown & Zuckerman, 1938;Zeiner, 1943).In all this work, the number offoetuses present in the rats were veryvariable, and it was thought desirable that a standard number of young should be left in the mother at the time of spaying. The present work was simplified by removing both ovaries simultaneously. In order to clarify the effects of the operation, it appeared necessary to spay one group of mother rats early in pregnancy and compare the subsequent findings with those after spaying at a relatively late stage. The number of foetuses in each pregnant rat was accordingly reduced to six on the 9th day as a standard procedure to obtain what is hereafter called the 'standardized' pregnant rat (Alexander & Frazer, 1954). Some rats were also spayed at this time, i.e. before the formation of the chorio-allantoic placenta, and these were compared with a similar series in which the operation of spaying was performed only 4 days before term.In rats spayed on the 9th day, it was expected that resorption of the foetuses might follow. If this should be the case, such a spayed rat would be a useful test animal to ascertain whether progesterone alone was sufficient to maintain pregnancy; and, if successful, whether other hormones and substances would also keep the foetuses alive. The ability to maintain pregnancy in an animal which would lose its foetuses in the absence of progesterone would certainly reveal any agent which had the essential properties of the latter.

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“…It cau ses an atrophy of the ovaries, m ostly tem porary, as noticed in the adult guinea-pig (Boling and Hamilton [1939]) and in mice (Robson [ 1938]). In the im m ature rats, testosterone propionate brought about follicle m aturation and luteinization without ovulation (Noble [ 1939]).…”

Section: Resultsmentioning

confidence: 99%