The eggs of mammals, by Gregory Pincus ...

Pincus, Gregory

doi:10.5962/bhl.title.6407

Cited by 52 publications

(5 citation statements)

References 101 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…It would seem more likely, however, that the oestrogen secreted by the follicle-bearing tissue caused the ova to be expelled from the tubes and also from the uterus, as was found to occur in the present experiments. A similar explanation probably accounted for the great variability in the rate of ovum transport in ovariectomized rabbits [Adams, 1958], in rabbits treated with oestrogen [Pincus & Kirsch, 1936;Whitney & Burdick, 1938], and in ovariectomized mice treated with oestrogen [Whitney & Burdick, 1936]. The rather consistent failure to recover between 20 and 30 % of the ova transferred into the tubes of the animals in the present experiment is considered to be due not only to the technical difficulties encountered in recovering ova, but in part to expulsion of ova from the ostium of the tube.…”

Section: Resultsmentioning

confidence: 98%

The Transport of Ova in Relation to the Dosage of Oestrogen in Ovariectomized Rabbits

Noyes¹,

Adams²,

Walton³

1959

Journal of Endocrinology

View full text Add to dashboard Cite

In order to determine what part the level of oestrogen in the body might play in the passage of ova through the female reproductive tract, 1249 freshly ovulated ova from donor rabbits were transferred into the uterine tubes of seventy-four ovariectomized recipients, fifty-three of which had previously been treated for 5-18 days with small daily injections of oestradiol benzoate. From 10 to 78 hr after transfer, 41 % of the ova were recovered from the uterine tubes, 9% from the uterine horns, and 23% from the vaginae of the recipient animals. Twenty-seven % of the ova were lost. The rate of ovum transport varied widely between similarly treated animals, and between the right and left sides of the reproductive tract of the same animal. Larger proportions of ova were retained in the uterine tubes, and smaller proportions in the uterine horns as the oestrogen dose was increased.The great variability in the stage of cleavage and in the thickness of the mucin coat of ova recovered from the uterus and vagina suggested that the ova might be widely dispersed through the uterine tubes and that they probably pass out of the uterine tube at widely different periods of time. Evidence is presented that ovum transport in ovariectomized rabbits with or without oestrogen treatment is very irregular, that ova may be ejected from either end of the uterine tube at almost any time after transfer, and that ova are not normally retained in the uteri of such animals.Approx. 1 \ g=m\ g oestradiol benzoate administered daily for 5-10 days was necessary to maintain the uterine weight of ovariectomized rabbits at about the same level as that in intact oestrous rabbits, and also to reduce the variability in egg transport observed in control and ovariectomized animals.Failure of the mechanisms that normally result in the transport of spermatozoa and ova through the female genital tract may be an important cause of reproductive loss in laboratory and farm animals. Considerable discrepancies between the numbers of ova ovulated and the numbers implanted have been reported in a wide variety of species (for review see Brambell [1948]). The studies of Hertig, Rock & Adams [1956] suggest that the failure of transport of the gametes may be the commonest cause of idiopathic infertility in women.The remarkable ability of the female genital tract to transport spermatozoa rapidly, though in restricted numbers, to the fertilization site in the uterine tube, and sub¬ sequently to transport the ova in the opposite direction, has been the subject of much study. The major factors involved in these processes are the relative sizes of the spermatozoa and ova, the motility of the spermatozoa, the action of tubai cilia, the contractility of tubai and uterine muscle, the secretion of cervical mucus and of tubai

show abstract

Section: Resultsmentioning

confidence: 98%

The Transport of Ova in Relation to the Dosage of Oestrogen in Ovariectomized Rabbits

Noyes¹,

Adams²,

Walton³

1959

Journal of Endocrinology

View full text Add to dashboard Cite

show abstract

“…These larger doses thus interfered with implantation after the ova had arrived in the uterus. That this interference with implantation is not due to a direct toxic effect of oestrogen on the ova was shown by Burdick, Whitney & Pincus [1937] and by Pincus & Kirsch [1936]. Disturbance of implantation may be due to an interference with maintenance of a progestational endometrium [Segal & Nelson, 1958], but the evidence available [Hain, 1935 ;Huggett & Pritchard, 1945] is not sufficient to determine the mechanism.…”

Section: Effect Of Oestronementioning

confidence: 93%

The Effects of Steroid Sex Hormones on Pregnant Rats

Dreisbach¹

1959

Journal of Endocrinology

View full text Add to dashboard Cite

Single doses of up to 0\ m=. \ 4mg/kg oestrone injected s.c. were found to interfere with pregnancy in the rat up to the 11th day post coitum (p.c.). As little as 0\m=.\02 mg/kg was effective during the period of tubal transport, while 0\m=.\1 mg/kg was necessary to prevent implantation after the ovum was free in the uterus. After implantation had taken place, 0\m=.\4 mg/kg injected on days 8, 9 or 10 destroyed some or all embryos or, if injected on days 10 or 11, caused delay in parturition. Delay in parturition was no longer reliably produced by the injection of 0\m=.\4mg/kg on the 16th day of gestation.A single dose of 4\m=.\0 mg/kg testosterone prevented implantation in 75 % of rats if injected s.c. during days 5-8 p.c., and produced either foetal loss or delay in parturition in 69 % of rats when injected on days 9-11 p.c. A single dose of 20 mg/kg testosterone was effective in all rats tested in preventing implantation if injected on days 1 and 5, producing foetal loss if injected on day 9 or delaying parturition if injected on days 11 and 16.A single dose of 4\m=.\0 mg/kg androst-5-ene-3\g=b\,17\g=b\-diolprevented implantation or caused foetal loss in 93 % of rats injected on days 5-11 p.c. This hormone was considerably more potent in preventing implantation and causing foetal loss than its androgenic potency as compared with testosterone would suggest. In contrast to testosterone, androst-5-ene-3\g=b\,17\g=b\-diol did not cause delay in parturition at doses up to 20 mg/kg. The effects of two other steroids tested, androst-4-ene-3,17-dione and 17\g=a\-methyl \x=req-\ androst-5-ene-3\g=b\,17\g=b\-diol, on pregnant rats were equivalent to or less than their androgenic potency would suggest.

show abstract

“…DMARDs suppress the in¯ammatory process and may slow the progression of joint erosion progression and reduce the possibility of functional disability if given at an early stage of the disease (11±14). The choice of DMARD depends on a balance of effectiveness and toxicity (15).…”

Section: Introductionmentioning

confidence: 99%