scholarly journals Early Pregnancy in the Ewe: Effects of Oestradiol and Progesterone on Uterine Metabolism and on Embryo Survival

1977 ◽  
Vol 30 (4) ◽  
pp. 279 ◽  
Author(s):  
BG Miller ◽  
NW Moore ◽  
Leigh Murphy ◽  
GM Stone
Keyword(s):  
Embryo Transfer ◽  
Embryo Development ◽  
Early Pregnancy ◽  
Protein Metabolism ◽  
Hormonal Regulation ◽  
Luteal Phase ◽  
Progesterone Receptors ◽  
Oestrous Cycle ◽  
Embryo Survival ◽  
Day Of Embryo Transfer

The hormonal regulation of embryo development during early pregnancy in the ewe has been examined. Ovariectomized ewes received injections of oestradiol (E2) and progesterone (P) according to schedules designed to simulate endogenous ovarian secretion during the luteal phase of the previous oestrous cycle (priming P), around the time of oestrus (oestrous E2 ) and during early pregnancy (maintenance P, maintenance E2)' Embryos were transferred to the ewes on the 4th day after induced oestrus, and ewes were killed at 6 or 13 days after transfer to assess embryo development. Cytosol concentrations of oestradiol 'and progesterone receptors and RNA and protein metabolism in the endometrium and amounts of protein in uterine flushings were examined on the day of embryo transfer and 6 days after transfer.

RNA AND PROTEIN METABOLISM IN THE OVIDUCT AND ENDOMETRIUM OF THE EWE AT PRO-OESTRUS: REGULATION BY OESTRADIOL AND PROGESTERONE

1976 ◽  
Vol 69 (1) ◽  
pp. 57-66 ◽  
Author(s):  
B. G. MILLER
Keyword(s):  
Protein Metabolism ◽  
Hormonal Regulation ◽  
Luteal Phase ◽  
Rna Synthesis ◽  
Model System ◽  
Oestrous Cycle ◽  
Cell Content ◽  
Hormone Effects ◽  
As Effects

SUMMARY The effects on RNA and protein metabolism in the oviduct and endometrium at pro-oestrus of oestradiol and progesterone secreted during the oestrous cycle were examined, using the ovariectomized, hormone-treated ewe as a model system. Thirty ewes received hormone injections during a period of 13 days, according to schedules designed to simulate endogenous ovarian secretion of oestradiol and progesterone during the oestrous cycle. Hormone effects on RNA:DNA ratios and on rates of synthesis of protein and methylated RNA in vitro, as well as effects on oviducal and uterine weight, were examined. The results obtained suggest that endogenous ovarian hormones have the following effects in the intact ewe. The secretion of oestradiol at pro-oestrus rapidly increases rates of synthesis of protein and methylated RNA, and mean cell content of RNA in both the endometrium and oviduct. Oestradiol secreted during the previous luteal phase of the oestrous cycle markedly increases mean cell content of RNA and amounts of protein and methylated RNA synthesis occurring in both tissues at pro-oestrus. In the endometrium, progesterone secreted during the luteal phase increases the RNA: DNA ratio, and probably also the amounts of protein and methylated RNA synthesized at pro-cestrus, but there are no significant interactions between the effects of oestradiol and progesterone. Progesterone had no effect on either the amounts or rates of synthesis of protein or methylated RNA in the oviduct. The results are discussed in relation to the hormonal regulation of physiological functions of the oviduct and endometrium during the first few days after the onset of oestrus.

Localization of oestradiol, progesterone and oxytocin receptors in the uterus during the oestrous cycle and early pregnancy of the ewe

1993 ◽  
Vol 138 (3) ◽  
pp. 479-NP ◽  
Author(s):  
D. C. Wathes ◽  
M. Hamon
Keyword(s):  
Progesterone Receptor ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Specific Binding ◽  
Progesterone Receptors ◽  
Oestrous Cycle ◽  
Luminal Epithelium ◽  
Paracrine Factors ◽  
Plasma Progesterone ◽  
Oxytocin Receptors

ABSTRACT Uterine tissue samples were collected from 47 ewes at various stages of the oestrous cycle and early pregnancy (until day 21) and during seasonal anoestrus. Cryostat sections were immunostained to determine the localization of oestradiol and progesterone receptors using specific monoclonal antibodies. Oxytocin receptors were localized by autoradiography in sections from the same ewes using the 125I-labelled oxytocin antagonist d(CH2)5[Tyr(Me)2,Thr4,Tyr-NH29]- vasotocin. Plasma progesterone measurements were made during the preceding cycle up to the time of slaughter. Oestradiol receptor concentrations were maximal in all regions of the tract at oestrus. Immunostaining of the luminal epithelium, superficial glandular epithelium, stroma and myometrium decreased in the early luteal phase but was maintained for longer in the deep glands. Progesterone receptor immunostaining in the luminal epithelium and superficial glands developed in the early luteal phase (days 1–2) with a somewhat later appearance in the deep glands (days 5–7). Progesterone receptor concentrations in the stroma and myometrium also reached a maximum in the early luteal phase. Myometrial staining was clearly maintained throughout the luteal phase whereas stromal staining was variable between ewes. For both oestradiol and progesterone receptors no differences were apparent between pregnant and non-pregnant ewes between days 2 and 12, but pregnant ewes did not show the general increases in oestradiol receptor staining associated with luteolysis on days 14–15. Oxytocin receptors first developed in the luminal epithelium of non-pregnant ewes on day 14 of the cycle and spread to the superficial glands, caruncular stroma, deep glands and myometrium at oestrus before decreasing in reverse order on days 1–2. Specific binding was not detectable on days 5–12 of the cycle or on days 14 or 21 of pregnancy. The appearance of oxytocin receptors in the luminal epithelium on day 14 preceded that of both the oestradiol and progesterone receptors in the epithelial cells and the fall in plasma progesterone. It was followed by the development of oestradiol and oxytocin receptors in the superficial glands, deep glands, caruncular stroma and myometrium, with the two receptor populations showing a significant positive association in these tissues. The loss of oxytocin receptors in all regions occurred as plasma progesterone levels were increasing, but the association between these two variables was only significant in the superficial glands. The development of progesterone receptors in different tissues could not be explained on the basis of either oestradiol receptor content or plasma progesterone. We conclude that all three receptor populations change in a dynamic manner during the oestrous cycle with variations both between days and between different uterine compartments. The complex pattern of receptor formation and loss suggests that, in addition to the circulating steroid hormone concentrations, local paracrine factors are likely to be involved in their regulation. Journal of Endocrinology (1993) 138, 479–491

Effect of undernutrition on uterine progesterone and oestrogen receptors and on endocrine profiles during the ovine oestrous cycle

2006 ◽  
Vol 18 (4) ◽  
pp. 447 ◽  
Author(s):  
C. Sosa ◽  
J. A. Abecia ◽  
F. Forcada ◽  
C. Viñoles ◽  
C. Tasende ◽  
...  
Keyword(s):  
Fatty Acids ◽  
Binding Capacity ◽  
Plasma Concentrations ◽  
Progesterone Receptors ◽  
Cell Types ◽  
Oestrous Cycle ◽  
Receptor Expression ◽  
Embryo Survival ◽  
Igf I ◽  
Maintenance Requirements

In the present study, it was investigated whether undernutrition affected the binding capacity, immunoreactivity and mRNA expression for uterine oestrogen and progesterone receptors (ER and PR, respectively) in sheep, as well as whether the responses were associated with changes in plasma concentrations of progesterone (P4), oestradiol (E2), glucose, fatty acids, insulin, leptin and insulin-like growth factor (IGF)-I during the oestrous cycle. Twenty ewes were fed either 1.5 (C) or 0.5 (L) times their maintenance requirements and were killed on Day 5 or 14 of the cycle (Day 0 = oestrus). Compared with Group C, Group L had higher concentrations of non-esterified fatty acids and lower concentrations of insulin, leptin and IGF-I. Group L also had higher plasma concentrations of P4 during the final days of the luteal phase. At oestrus in both treatment groups, there were peaks in the concentrations of glucose, insulin and IGF-I. For ER and PR, transcript expression, binding capacity and immunoreactivity were higher on Day 5 than on Day 14 of the cycle. The binding capacities for ER and PR were lower in Group L than in Group C on Day 5. Group C showed more immunoreactive staining for ER than did Group L in two of five cell types, whereas no effect of treatment was observed for PR immunoreactivity. There was more PR mRNA in the uterine horn contralateral to the corpus luteum in Group C than in Group L ewes. We conclude that undernutrition impairs steroid receptor expression and binding capacity. This may alter the uterine environment and help explain the reductions in embryo survival.

Development of the Technique of Oocyte Donation and Hormonal Replacement Therapy: is Oestrogen Really Necessary for the Establishment and Maintenance of Pregnancy?

1992 ◽  
Vol 4 (6) ◽  
pp. 671 ◽  
Author(s):  
A Trounson
Keyword(s):  
Replacement Therapy ◽  
Embryo Transfer ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Oocyte Donation ◽  
Follicular Phase ◽  
The Other ◽  
Normal Menstrual Cycle ◽  
Constant Dose ◽  
Sequential Regimen

The technique for oocyte donation to women with hypergonadotrophic hypogonadism was modelled on the requirements for ovarian steroid replacement therapy in ovariectomized ewes. In the sheep, it is apparent that a period of priming progesterone, follicular-phase oestrogen and luteal-phase progesterone is required to enable embryo development following embryo transfer; the timing of embryo transfer is governed by the actual dose of luteal-phase progesterone. The horse, on the other hand, requires only progesterone to establish a receptive uterus for transferred embryos. Although a sequential regimen of oestrogen and progesterone that mimics the hormonal profiles in a normal menstrual cycle is very efficient in effecting pregnancy by oocyte donation in women, much simpler regimens have been devised that produce a variable-length follicular phase by using a constant dose of oestrogen and a constant dose of progesterone for the luteal phase and early pregnancy. It is suggested that ovarian oestrogen is not essential for the luteal phase and early pregnancy, and may not even be required for the establishment of pregnancy. It is also apparent that progesterone replacement may cease before the luteoplacental shift is detected, without necessarily interrupting pregnancy, suggesting that local embryo or placenta-derived steroids may effectively maintain early pregnancy in the human.

scholarly journals Chemerin Affects P4 and E2 Synthesis in the Porcine Endometrium during Early Pregnancy

2022 ◽  
Vol 23 (2) ◽  
pp. 945
Author(s):  
Marlena Gudelska ◽  
Kamil Dobrzyn ◽  
Marta Kiezun ◽  
Katarzyna Kisielewska ◽  
Edyta Rytelewska ◽  
...  
Keyword(s):  
Western Blot ◽  
Early Pregnancy ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Signalling Pathway ◽  
Signalling Pathways ◽  
Steroidogenic Enzyme ◽  
Akt Phosphorylation ◽  
Pathway Activation

Chemerin, belonging to the adipokine family, exhibits pleiotropic activity. We hypothesised that the adipokine could be involved in the regulation of steroidogenesis in the porcine endometrium. Thus, the aim of this study was to determine the effect of chemerin on the key steroidogenic enzyme proteins’ abundance (Western blot), as well as on P4 and E2 secretion (radioimmunoassay) by the porcine endometrium during early pregnancy and the mid-luteal phase of the oestrous cycle. Moreover, we investigated the hormone impact on Erk and Akt signalling pathway activation (Western blot). Chemerin stimulated E2 production on days 10 to 11 of pregnancy. On days 10 to 11 and 15 to 16 of gestation, and on days 10 to 11 of the cycle, chemerin enhanced the expression of StAR and all steroidogenic enzyme proteins. On days 12 to 13 of pregnancy, chemerin decreased StAR and most of the steroidogenic enzyme proteins’ abundance, whereas the P450C17 abundance was increased. On days 27 to 28 of pregnancy, chemerin increased StAR and P450C17 protein contents and decreased 3βHSD protein amounts. It was noted that the adipokine inhibited Erk1/2 and stimulated Akt phosphorylation. The obtained results indicate that chemerin affected P4 and E2 synthesis through the Erk1/2 and Akt signalling pathways.

Circulating concentrations of oxytocin during pregnancy in ewes

1984 ◽  
Vol 106 (2) ◽  
pp. 277-281 ◽  
Author(s):  
D. Schams ◽  
A. Lahlou-Kassi
Keyword(s):  
Early Pregnancy ◽  
Luteal Phase ◽  
Oestrous Cycle ◽  
Slight Effect ◽  
Unknown Mechanism ◽  
Maternal Recognition Of Pregnancy ◽  
Time Courses

Abstract. Oxytocin and progesterone were measured radioimmunologically during a control cycle, early pregnancy and during several time courses until term in 4 ewes of a local Maroccan breed of sheep. Oxytocin concentrations increased in a similar matter after day 3–4 of the control cycle or after mating and decreased on days 13–15 of early pregnancy about 2 days earlier than during the oestrous cycle. After days 18–19 of pregnancy oxytocin concentrations remained low until term at concentrations as observed during the non-luteal phase of the oestrous cycle. Contrary progesterone concentrations remained high throughout gestation. Maternal recognition of pregnancy seems to have only a slight effect on the secretion pattern of oxytocin for few days after day 12. The results indicate a similar unknown mechanism during the cycle and early pregnancy for the vanishing oxytocin secretion and perhaps synthesis.

Effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on progesterone concentrations and embryo survival in sheep

1987 ◽  
Vol 112 (2) ◽  
pp. 205-213 ◽  
Author(s):  
C. J. Ashworth ◽  
I. Wilmut ◽  
A. J. Springbett ◽  
R. Webb
Keyword(s):  
Luteal Phase ◽  
Hydroxysteroid Dehydrogenase ◽  
Oestrous Cycle ◽  
Silicone Elastomer ◽  
Progesterone Concentration ◽  
Embryo Survival ◽  
Progesterone Production ◽  
Group 3 ◽  
Group 2 ◽  
Group 1

ABSTRACT The effect of an inhibitor of 3β-hydroxysteroid dehydrogenase on peripheral progesterone concentration during the luteal phase of the oestrous cycle and on embryo survival was determined in sheep. Following administration of 10, 50, 100 or 250 mg epostane (4,5-epoxy-17-hydroxy-4,17,dimethyl-3-oxo-androstane-2-carbonitrile) progesterone concentrations were significantly lower than control levels 4 h after injection, from 2·5 to 22 h, 1·5 to 24 h and 1 to 24 h after injection respectively. There appeared to be no effect on peripheral oestradiol concentrations. Adrenal progesterone production was small and not influenced by epostane treatment. Epostane was administered on day 9 of the oestrous cycle to cause a reduction in progesterone concentrations for approximately 12-18 h on day 9 only (group 1, 250 mg epostane on day 9), or a series of such reductions on 3 consecutive days (group 2, 50 mg epostane on days 9, 10 and 11) or a continuous reduction for 3 days (group 3, 250 mg epostane on days 9, 10 and 11). The proportion of ewes that were pregnant was significantly (P<0·05) lower in ewes treated to give a continuously low progesterone concentration for 3 days than in either controls or ewes in which progesterone concentration was reduced for less than 24 h (in controls and groups 1, 2 and 3 the proportion was 85, 92, 54 and 18% of ewes treated respectively). Embryo survival was not affected by administration of 250 mg epostane on days 9, 10 and 11 if luteal phase levels of progesterone were maintained by insertion of a silicone elastomer implant of the steroid. The proportion of embryos surviving was 72% in controls compared with 78% in the treated animals. J. Endocr. (1987) 112, 205–213

Corpus luteum life span and pituitary oestrogen and progesterone receptors in cyclic and gonadotrophin-releasing hormone-treated anoestrous ewes

2005 ◽  
Vol 17 (7) ◽  
pp. 721 ◽  
Author(s):  
C. Tasende ◽  
M. Rodríguez-Piñón ◽  
S. Acuña ◽  
E. G. Garófalo ◽  
M. Forsberg
Keyword(s):  
Luteal Phase ◽  
Luteinising Hormone ◽  
Binding Assay ◽  
Hormone Secretion ◽  
Progesterone Receptors ◽  
Oestrous Cycle ◽  
Inhibitory Effects ◽  
Releasing Hormone ◽  
Expected Time ◽  
Gonadotrophin Releasing Hormone

The present study investigated the pituitary oestrogen (ER) and progesterone (PR) receptor concentrations in ewes during the oestrous cycle in the breeding season (n = 19), and in anoestrous ewes treated with gonadotrophin-releasing hormone (GnRH) (n = 11) and anoestrous ewes treated with progesterone + GnRH (n = 11). The pituitary ER and PR concentrations at the expected time of ovulation and in the early and late luteal phases were measured by binding assay. The pattern of pituitary ER and PR concentrations in the progesterone + GnRH-treated ewes resembled the pattern found during the normal oestrous cycle, with ER and PR concentrations decreasing from the time of ovulation to the early luteal phase. In contrast, in ewes treated with GnRH alone, ER and PR concentrations increased in the early luteal phase, which may increase the inhibitory effects of steroid hormones on luteinising hormone secretion, ultimately leading to the development of subnormal luteal phases.

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