Role of conceptus secretory products in establishment of pregnancy

Bazer, Fuller W.; Vallet, J. L.; Roberts, R. M.; Sharp, Daniel C.; Thatcher, W.W.

doi:10.1530/jrf.0.0760841

Cited by 185 publications

(61 citation statements)

References 39 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The results obtained suggested that the metabolism of 17α-hydroxyprogesterone, 20α-hydroxyprogesterone, 20β-hydroxyprogesterone and androgen did not differ between parthenogenetic and fertilized blastocysts, whereas the metabolism of progesterone and estrogen was lower in parthenogenetic blastocysts. Estrogen synthesized by embryos is thought to involve the transformation from morulae to blastocysts [25,26] and maternal recognition of blastocysts [27][28][29]. From the results of this study on estrogen metabolism, it can be concluded that the functions [25][26][27][28][29] mentioned above are low in parthenogenetic embryos, and that the low potential of development in parthenogenetic embryos is due to their low estrogen metabolism, in addition to the previous findings [1-3, 5-8, 18-24].…”

Section: Discussionsupporting

confidence: 58%

“…Estrogen synthesized by embryos is thought to involve the transformation from morulae to blastocysts [25,26] and maternal recognition of blastocysts [27][28][29]. From the results of this study on estrogen metabolism, it can be concluded that the functions [25][26][27][28][29] mentioned above are low in parthenogenetic embryos, and that the low potential of development in parthenogenetic embryos is due to their low estrogen metabolism, in addition to the previous findings [1-3, 5-8, 18-24]. In the present study, however, there were many parthenogenones with low metabolism of estrogen and progesterone, even those developed into blastocysts.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

A Histochemical Study of the Steroid Metabolism in Parthenogenetic Mouse Blastocysts.

Niimura

Asami

1997

Journal of Reproduction and Development

View full text Add to dashboard Cite

Abstract. The activities of hydroxysteroid dehydrogenases (HSDs) and adenylate cyclase in parthenogenetic mouse blastocysts derived from the ova activated and diploidized by the treatment of ethanol and cytochalasin B were histochemically examined, and were compared with those in control blastocysts developed from fertilized ova. Although the activities of ∆ 5 -3β-HSD with DHA and 17α-hydroxypregnenolone as the substrates, 17β-HSD with testosterone, 20α-HSD and 20β-HSD did not differ between parthenogenetic and control blastocysts, the activities of ∆ 5 -3β-HSD with pregnenolone as the substrate, 17β-HSD with estradiol-17β and adenylate cyclase were significantly lower in parthenogenetic blastocysts. These results suggest that the metabolism of 17α-hydroxyprogesterone, 20α-hydroxyprogesterone, 20β-hydroxyprogesterone and androgen in parthenogenetic blastocysts is comparable to that in control blastocysts, whereas the metabolism of progesterone, estrogen and cyclic AMP in parthenogenetic blastocysts is low compared with that in control blastocysts. When parthenogenetic blastocysts were treated with hCG, the activities of ∆ 5 -3β-HSD with pregnenolone as the substrate and 17β-HSD with estradiol-17β were stimulated, but were still lower than those of control blastocysts. The low potential of development in parthenogenetic embryos was discussed in relation to their steroid metabolism. [7] have been studied in the mouse, and the metabolism or synthesis of these substances has been found to be low, compared with that of fertilized embryos. It has also been reported histochemically that the ability of digestion and of interconversion between carbohydrate and lipid are lower in parthenogenetic mouse blastocysts than in blastocysts developed from fertilized ova [8]. Thus, such low metabolic activities in parthenogenetic embryos are thought to be a reason for lower potentials of development in these embryos [5][6][7][8]. However, there have been no reports in which the metabolism of substances, other than is stated that the proportion of nucleolonema in the nucleolus in these embryos is higher than that in fertilized embryos, and parthenogenetic embryos have many mitochondria with vacuolated cristae, but very few cytoplasmic organelles, such as Golgi apparatus, lysosomes and ribosomes. It has also been determined in morphological studies of the mouse that the contents of lipid droplets and crystalloids are fewer in parthenogenetic blastocysts than in blastocysts developed from fertilized ova [1,4]. From these results, it has been assumed that the metabolic activity is lower in parthenoge-

show abstract

Section: Discussionsupporting

confidence: 58%

Section: Discussionmentioning

confidence: 99%

A Histochemical Study of the Steroid Metabolism in Parthenogenetic Mouse Blastocysts.

Niimura

Asami

1997

Journal of Reproduction and Development

View full text Add to dashboard Cite

show abstract

“…The present results show that ER (and PR) disappear from the LE and are reduced in the GE and stroma in the mare, much like that shown for ruminants. Perhaps this explains the inability of exogenous oestrogen to lengthen luteal lifespan in mares as shown for pigs (see Bazer et al 1986). …”

Section: Discussionmentioning

confidence: 98%

Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares

Hartt¹,

Carling²,

Joyce³

et al. 2005

Reproduction

View full text Add to dashboard Cite

Uterine function is primarily controlled by the combined actions of oestrogen and progesterone working through their cognate nuclear receptors. The mechanism of establishment of pregnancy in the mare is of interest because it involves prolonged pre-attachment and conceptus migration phases, and both invasive and non-invasive placental cell types, and as such has been an important comparative model. This study characterised regulation of oestrogen (ER) and progesterone (PR) receptors in the endometrium of the mare during the oestrous cycle and early pregnancy. Endometrial tissues collected during the oestrous cycle and early pregnancy were analysed for steady-state levels of ER and PR mRNA and protein. Steady-state levels of ER and PR mRNA were highest on days 0, 17 and 20 in cyclic mares and lowest on days 11 and 14. A day-by-status interaction was detected, indicating that day 17 and day 20 pregnant mares exhibited low levels of ER and PR compared with the corresponding days of the oestrous cycle. In situ hybridisation analyses showed receptor mRNA localisation primarily in the luminal epithelium (LE), glandular epithelium (GE) and stroma around oestrus. During dioestrus and early pregnancy, receptors were not detected in the LE, and were lower in the stroma and deeper GE. Changes in hybridisation intensity in these cell types were consistent with changes in mRNA levels detected by slot-blot hybridisation. ER and PR proteins were detected in the nuclei of LE, GE and stromal cells. Consistent with results from in situ hybridisation, levels of ER and PR immunoreactivity were higher around oestrus, declined to low levels during dioestrus and remained low during early pregnancy. Results described here for temporal and spatial changes in steroid receptor gene expression in mares show the greatest similarities with those described for cattle and sheep.

show abstract

“…Communication between the maternal uterine environment and the embryo is known to be vitally important to the establishment of pregnancy in normally cycling ewes and is mediated via secretions from both the endometrium and the embryo (Bazer & Roberts, 1983;Bazer et al, 1986). As yet we have no information on the biochemical nature of the endometrial/ conceptus secretions in the early post-partum ewe but it is possible that abnormal or asynch¬ ronous bi-directional signalling between them may be contributing to pregnancy failure in…”

Section: Discussionmentioning

confidence: 99%

Does inadequate luteal function limit the establishment of pregnancy in the early post-partum ewe?

Wallace¹,

Robinson²,

Aitken³

1989

Reproduction

View full text Add to dashboard Cite

observed in 2 of 7 (0\m=.\28)lactating and 4 of 9 (0\m=.\44)early weaned ewes compared with corresponding values of 1 of 13 (0\m=.\08) and 2 of 11 (0\m=.\18) in the 35-day post-partum group. Luteal function was normal in all standard ewes. The proportion of successful pregnancies in the standard ewes was 0\m=.\80 (12 of 15) compared with 0 in lactating and early weaned ewes in the 21-day group and 0\m=.\08 (1 of 13) and 0\m=.\36 (4 of 11) respectively in the 35-day group.The incidence of inadequate luteal function is therefore independent of the suckling stimulus and is higher in ewes induced to ovulate on Day 21 than Day 35 post partum during breeding and non-breeding seasons. For early post-partum recipient ewes with normal luteal function it is suggested that the high incidence of pregnancy failure after transfer of embryos may be due to embryo mortality caused by an inappropriate uterine environment or the inability of the embryo to sustain its luteotrophic signal.

show abstract

Role of conceptus secretory products in establishment of pregnancy

Cited by 185 publications

References 39 publications

A Histochemical Study of the Steroid Metabolism in Parthenogenetic Mouse Blastocysts.

A Histochemical Study of the Steroid Metabolism in Parthenogenetic Mouse Blastocysts.

Temporal and spatial associations of oestrogen receptor alpha and progesterone receptor in the endometrium of cyclic and early pregnant mares

Does inadequate luteal function limit the establishment of pregnancy in the early post-partum ewe?

Contact Info

Product

Resources

About