Oestrogen production by blastocyst and early embryonic tissue of various species

Gadsby, John E.; Heap, R. B.; Burton, Robert D.

doi:10.1530/jrf.0.0600409

Cited by 138 publications

(70 citation statements)

References 26 publications

(17 reference statements)

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“…The blastocyst itself most likely contributes to the hormonal mechanisms leading to its own implantation [24]. In some species, oestrogens are produced by the blastocyst, which might then implant without any maternal oestrogen surge [25]. In the rat, such hormonal contributions from the blastocyst have been debated, but not proven [13].…”

Section: Discussionmentioning

confidence: 99%

Oestrogen and progestogen receptors in endometrium and myometrium at the time of blastocyst implantation in pregnant diabetic rats

Hertogh¹,

Vanderheyden²,

Glorieux³

et al. 1989

Diabetologia

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Summary.A suitable hormonal environment is a prerequisite for blastocyst implantation. Experimental diabetes was previously shown to modify the hormonal milieu and produce alterations in oestrogen receptor kinetics in the uterine tissue. In the present work, oestrogen and progestogen receptor levels were measured on the morning of day 6 of pregnancy in normal and in streptozotocin-induced diabetic rats, both in implantation sites and in interembryonic segments of endometrium and myometrium. Receptor levels were different in the implantation sites compared to the interembryonic segments of endometrium, both in the control and in the diabetic animals. Indeed, implantation sites were characterized by lower oestrogen receptor levels in cytosol and higher progestogen receptor levels in cytosol and nuclei. However, compared to the control rats, the diabetic rats had lower oestrogen receptor levels in implantation sites, both in cytosol and nuclei. In the myometrium, the differences between sites or between types of rats were minimal. Plasma levels of oestradiol were lower in diabetic rats than in control animals, whereas progesterone levels were similar. A 20% lower implantation rate was found in diabetic rats, compared to normal rats. These results show that the specific distribution of oestrogen and progestogen receptors between implantation sites and interembryonic segments was preserved in the diabetic rats; however the absolute level of oestrogen receptor was lower. This abnormal endocrine milieu might arise from a lower oestradiol level and a decreased oestradiol/progesterone ratio in the circulating blood. Whether the lower implantation rate in diabetic rats might be a consequence of the overall disturbed hormonal status remains to be elucidated.

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Section: Discussionmentioning

confidence: 99%

Oestrogen and progestogen receptors in endometrium and myometrium at the time of blastocyst implantation in pregnant diabetic rats

Hertogh¹,

Vanderheyden²,

Glorieux³

et al. 1989

Diabetologia

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“…Pig blastocysts begin to secrete large quantities of oestrogen and elongate after attaining a spherical diameter of 10 mm on about Day 11-5 of gestation (Gadsby et al, 1980;Geisert et al, 1982a;Fischer et al, 1985). The uterine secretory response induced by blastocyst oestrogen release can also be mimicked by exogenous oestrogen administration (Geisert et al, 1982c).…”

Section: Introductionmentioning

confidence: 99%

Development and survival of pig blastocysts after oestrogen administration on Day 9 or Days 9 and 10 of pregnancy

et al. 1987

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These results indicate that oestradiol treatment on Day 9 of pregnancy advances uterine secretory response, but that blastocyst elongation can occur in this uterine environment and in the presence of declining intraluminal Ca2+ levels. However, the blastocysts fail to survive to Day 16, presumably due to failure of attachment because of an alteration in the uterine secretory environment and/or changes in uterine surface proteins.

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“…Oestradiol increases the rate of protein synthesis and decreases net production of PGF in caruncular tissue (Findlay et al, 1981); it stimulates uterine blood flow when injected into the circulation (Greiss & Anderson, 1970b) or into the uterine lumen (Greiss & Miller, 1971); and reduces the vasoconstrictor response of the uterine artery to sympathetic nerve stimulation (Ford, Weber & Stormshak, 1977). However, the production of oestrogens by the sheep conceptus during the peri-implantation period could not be demonstrated (Gadsby, Heap & Burton, 1980;Heap et al, 1981), though this may be due to an inability to detect a low level of activity rather than a complete absence of oestrogen production.…”

Section: Introductionmentioning

confidence: 99%

Uterine blood flow, myometrial activity and their response to adenosine during the peri-implantation period in sheep

Fleet¹,

Heap²

1982

Reproduction

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Summary. Uterine blood flow and myometrial activity were measured simultaneously in anaesthetized sheep 15 days after a sterile (non-pregnant group) or fertile (pregnant) mating. During the peri-implantation period uterine blood flow was similar in both groups of animals, but spontaneous myometrial activity was greatly reduced in pregnant ewes. This 'block' of myometrial activity was associated with circulating levels of progesterone which were significantly higher (2\m=.\8\ m=+-\0\m=.\8ng/ml, mean \m=+-\ s.e.m.) than those in non-pregnant animals (0\m=.\4 \m=+-\0\m=.\3 ng/ml). Adenosine injected into the uterine artery produced uterine vasodilatation in both groups, but the log dose\p=n-\response was significantly less in pregnant than in non-pregnant animals (P < 0\m=.\001).Myometrial activity was stimulated by adenosine, particularly in the pregnant group (P < 0\m=.\001

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Oestrogen production by blastocyst and early embryonic tissue of various species

Cited by 138 publications

References 26 publications

Oestrogen and progestogen receptors in endometrium and myometrium at the time of blastocyst implantation in pregnant diabetic rats

Oestrogen and progestogen receptors in endometrium and myometrium at the time of blastocyst implantation in pregnant diabetic rats

Development and survival of pig blastocysts after oestrogen administration on Day 9 or Days 9 and 10 of pregnancy

Uterine blood flow, myometrial activity and their response to adenosine during the peri-implantation period in sheep

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