Proceedings: progesterone requirements for the maintenance of pregnancy in the ovariectomized ewe

Nw, Moore

doi:10.1530/jrf.0.0430386

Cited by 13 publications

(7 citation statements)

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“…A total of 9 recipients had a corpus luteum that seemed small for the stage of the cycle, appeared cyanotic, or possessed either no crown or a small crown. Serum progester¬ one concentrations in these females (2-58 ±0-51 ng/ml) were comparable to those in females ( (Moore, 1975) and with asynchronous transfer (Lawson, 1977) show that subtle differences in the hormonal milieu can have profound effects on embryonic development. The progesterone levels in pregnant and non-pregnant cows on Days 9-14 closely resemble those reported by Shemesh et al (1968) and Pope et al (1969) (Henricks et al, 1971;Erb et al, 1976) and Day 13 after oestrus (Holness et al, 1977).…”

Section: Introductionmentioning

confidence: 50%

Serum progesterone concentrations in cows receiving embryo transfers

Hasler¹,

Bowen²,

Nelson³

et al. 1980

Reproduction

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Summary. Progesterone concentrations in systemic blood were determined by radioimmunoassay in crossbred cattle used as recipients in an embryo transfer programme. An embryo was transferred surgically to the uterine horn of 528 females which were in oestrus within one half-day of the donor. Jugular blood was obtained at the time embryos were transferred (3\p=n-\7days after oestrus) and again from most females between Days 9 and 14. Pregnancy was determined by rectal palpation 45\p=n-\ 65 days after oestrus. There were no significant differences between serum progesterone levels of females which remained pregnant and those which did not. Out of 177 pregnant recipients, none had serum progesterone levels <0\m=.\5ng/ml on Days 10, 11, or 12 but in 8, values were <1\m=.\0 ng/ml. Blood samples were also taken on Days 20, 21, or 22 from 113 of these recipients. The mean \ m=+-\ s.e.m. concentration of progesterone in the pregnant females (5\m=.\14\ m=+-\0\m=.\34 ng/ml) was significantly higher (P < 0\m=.\001)than in the non-pregnant females (1\m=.\17\ m=+-\ 0\m=.\25ng/ml). The correlation coefficients between progesterone levels on Days 3, 4, 5 or 6 and 10\p=n-\12 ranged from 0\m=.\18to 0\m=.\37 (all P < 0\m=.\02).Progesterone levels were not related to length of the previous cycle, the time of day an animal was first noticed in oestrus or the side of the corpus luteum. However, cows with a short oestrus had higher progesterone levels on Days 3\p=n-\7(P < 0\m=.\01) than those in oestrus for a longer time.

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Section: Introductionmentioning

confidence: 50%

Serum progesterone concentrations in cows receiving embryo transfers

Hasler¹,

Bowen²,

Nelson³

et al. 1980

Reproduction

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“…Previous studies in the ewe have demonstrated that administration of exogenous progesterone early in pregnancy allows older embryos to be transferred and maintained in 'younger' uteri (Moore, 1975;Lawson & Cahill, 1983;Vincent et ai, 1985). Day-8 cattle embryos can establish pregnancy when transferred to Day-5 recipient cows treated with progesterone compared with asynchronous controls (T. C. Fox & R. D. Geisert, unpublished).…”

Section: Discussionmentioning

confidence: 99%

“…Previous studies in the ewe have shown that progesterone administration during the first fe days of the oestrous cycle allowed recipient ewes to accept and maintain older conceptuses succès fully after embryo transfer (Moore, 1975;Lawson & Canili, 1983;Vincent et al, 1985). These dal suggest that progesterone administration to recipients during the early oestrous cycle results i specific changes within the uterine environment which accommodate conceptuses at a moi advanced stage.…”

Section: Introductionmentioning

confidence: 99%

Evidence for maternal regulation of early conceptus growth and development in beef cattle

Garrett

Geisert²,

Zavy³

et al. 1988

Reproduction

344

155

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Fifty-one cyclic beef cows were mated with fertile bulls. At 36 h after the start of oestrus, cows were assigned to receive sesame oil (controls) or progesterone (100 mg) on Days 1, 2, 3 and 4 of pregnancy. Peripheral plasma concentration of progesterone was measured until slaughter on Days 5 or 14. Cows were randomly assigned to be slaughtered on Days 5 or 14 or remain intact and palpated per rectum on Day 40 to verify pregnancy. Uteri on Days 5 and 14 were flushed for recovery of luminal protein and conceptus tissue. Conceptus and endometrial tissues were cultured with [3H]leucine and submitted to two-dimensional-PAGE and fluorography. Administration of progesterone increased peripheral plasma progesterone concentration on Day 2-5. Conceptuses recovered from progesterone-treated cows on Day 14 were advanced in development compared to conceptuses from control cows. Conceptuses recovered from progesterone-treated cows were viable as polypeptides associated with maintenance of pregnancy in cattle were synthesized and released at an earlier time and pregnancy was maintained beyond Day 40. Early progesterone stimulation altered the synthesis and release of polypeptides from endometrial explant cultures on Day 5. Results indicate a role of progesterone in the maternal regulation of conceptus growth and development in early pregnancy of cattle.

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“…embryo development to changes in the uterine environment, by also examining changes in RNA and protein metabolism within the genital tract. Portions of this study have been briefly described elsewhere (Moore 1975;Miller and Moore 1976;Moore and Miller 1976). 0·50 1·00 0·625 1·25 0'75 1·50 1·00 2·00 1·25 2·50 1·50 3·00 2·0 4·0 2·5 5·0 3·0 6·0 4·0 Mature parous Merino ewes were used in the study and they had been bilaterally ovariectomized at least 2 months prior to the commencement of the experiments.…”

Section: Introductionmentioning

confidence: 99%

Effects of Progesterone and Oestradiol on RNA and Protein Metabolism in the Genital Tract and on Survival of Embryos in the Ovariectomized Ewe

Miller¹,

Moore²

1976

Aust. Jnl. Of Bio. Sci.

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The hormonal regulation of metabolism in the genital tract and the development of embryos during early pregnancy in the ewe have been examined. Ovariectomized ewes received injections of main· tenance progesterone, oestrous oestradiol and priming progesterone according to schedules designed to simulate endogenous ovarian secretion during early pregnancy, around the time of oestrus and during the luteal phase of the oestrous cycle immediately preceding oestrus.The survival and development of embryos was dependent upon the dose of maintenance progesterone and the duration of treatment at the time of transfer, but changes in progesterone dose did not change endometrial protein or RNA metabolism on particular days. Both priming progesterone and oestrous oestradiol were required for normal embryo development. Priming progesterone and oestrous oestradiol each increased endometrial RNA/DNA ratios during early pregnancy. There were no interactions between priming progesterone and oestrous oestradiol, their effects being simply additive. Neither maintenance nor priming progesterone had any effect on protein and RNA metabolism in the oviduct. It is suggested that in the intact ewe oestrogen secreted at oestrus and progesterone secreted prior to oestrus play important roles in the establishment of a uterine environment suitable for the subsequent normal development of embryos.

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Proceedings: progesterone requirements for the maintenance of pregnancy in the ovariectomized ewe

Cited by 13 publications

References 0 publications

Serum progesterone concentrations in cows receiving embryo transfers

Serum progesterone concentrations in cows receiving embryo transfers

Evidence for maternal regulation of early conceptus growth and development in beef cattle

Effects of Progesterone and Oestradiol on RNA and Protein Metabolism in the Genital Tract and on Survival of Embryos in the Ovariectomized Ewe

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