The secretion of prostaglandin F from the autotransplanted uterus of the ewe

Scaramuzzi, R. J.; Baird, D. T.; Boyle, H. P.; Land, R. B.; Wheeler, A. G.

doi:10.1530/jrf.0.0490157

Cited by 35 publications

(13 citation statements)

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“…The high number of new ovulations in ewes immunized against progesterone, despite the persistence of the corpora lutea from the previous ovulations, indicated that prostaglandin F2a was either not being synthesized and/or released. Since treatment of ovary-intact ewes with progesterone early in the oestrous cycle shortens the length of the cycle by advancing the release of prostaglandin F2a (Wodzicka-Tomaszewska et al 1974;Ottobre et al 1980), and treatment of ovariectomized ewes with progesterone also increases the level of prostaglandin F2a (Scaramuzzi et al 1977), the present observations confirm that either the synthesis or the release of prostaglandin F2a depends on prior exposure of the endometrium to high concentrations of free progesterone.…”

Section: Methodssupporting

confidence: 73%

“…Furthermore, the priming of anoestrous ewes with progesterone prior to the induction of ovulation by the introduction of rams ('ram effect') or using repeated injections of gonadotrophin releasing hormone (GnRH) ensures that the resulting corpora lutea do not regress prematurely (Cognie et al 1982;McLeod et al 1982), implying some direct ovarian site of action of progesterone. Moreover, progesterone has also been shown to be involved in the control of the tonic secretion of LH (Goodman and Karsch 1980) and to prime the uterus for the release of prostaglandin (Scaramuzzi et al 1977).…”

Section: Introductionmentioning

confidence: 99%

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Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe

Thomas¹,

Oldham²,

Hoskinson³

et al. 1987

Aust. Jnl. Of Bio. Sci.

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The effects of active immunization against progesterone on reproductive activity were studied in Merino ewes. Immunization against progesterone caused a shortening (P < 0'01) of the interval between ovulations from 17-18 days (controls) to between 6 and 10 days (immunized group); this was associated with a corresponding reduction in the interval between LH surges. The immunized ewes also had higher (P < O· 05) ovulation rates (1' 72) than controls (I. 25) and exhibited a reduced (P < 0'01) incidence of oestrus (26% v. 95%). Many immunized ewes continued to ovulate despite the persistence of corpora lutea from earlier ovulations which led to an accumulation on the ovaries of many corpora lutea of different ages. The frequency of LH pulses in ewes immunized against progesterone (1'8 ± 0·2 pulses/4 h) was significantly (P < 0'001) higher than that of control ewes (0'3 ± 0·1 pulses/4 h). This study highlights the importance of progesterone in the control of oestrus, ovulation, ovulation rate, luteal regression and the secretion of LH in the ewe.

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Section: Methodssupporting

confidence: 73%

Section: Introductionmentioning

confidence: 99%

Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe

Thomas¹,

Oldham²,

Hoskinson³

et al. 1987

Aust. Jnl. Of Bio. Sci.

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“…Perhaps two of the most important agents known to influence this process are the ovarian steroids, oestradioLl7p and progesterone (Barcikowski et al, 1974;Shemesh et al, 1975;Baird et al, 1976;Scaramuzzi et al, 1977). The action of oestradiol-17p on a progesterone-primed endometrium is thought to provide the optimum conditions for the predominant synthesis of PGF,, (Caldwell et al, 1972;Blatchley et al, 1975;Castracane and Jordan, 1975).…”

Section: Discussionmentioning

confidence: 99%

Prostaglandin Synthesis in the Endometrium of Women With Ovular Dysfunctional Uterine Bleeding

Smith

Abel

Kelly

et al. 1981

BJOG

Self Cite

219

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Summary The endogenous concentrations of prostaglandins F2α (PGF2α) and E (PGE) were measured during the luteal phase of the menstrual cycle in the endometrium from 14 women with unexplained menorrhagia (measured menstrual blood loss in excess of 50 ml) and 15 women with normal menses (blood loss 50 ml or less). Although there was no significant difference in the PGF 2α/PGE ratio between the two groups, this ratio was significantly lower in the endometrium from eight of the women whose blood loss exceeded 90 ml (p <0.05). There was a significant inverse correlation between the PGF2α/PGE ratio and blood loss (r = 0.36, p <0.025). The synthetic capacity of the endometrium was assessed by incubation of the tissue with 14C arachidonic acid. Endometria from nine women with unexplained menorrhagia synthesized more PGE2 than PGF2α, whereas the converse was true with 11 control endometria. Consequently the PGF2α/PGE2 ratio was significantly reduced in the former group (p <0.025). Oestradiol‐17β (200 μM) and to a greater extent 2 hydroxy oestradiol (200 μM) increased the total prostaglandin synthesis by the endometria, but did not significantly alter the PGF2α/PGE2 ratio. These results suggest that excessive blood loss may be associated with a shift in the endometrial conversion of prostaglandin endoperoxide from PGF2α to PGE2.

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“…However, there are changes in protein secretion by the uterus during the normal cycle and early pregnancy as indicated by studies of proteins in uterine flushings (Menezo, 1973;Roberts, Parker & Symonds, 1976) and enzyme activities in uterine tissues (Murdoch, 1970a, b;Zamiri & Blackshaw, 1979). However, these changes have not been studied in relation to PG production in different tissues within the uterus, although it is well known that PGF-2a production (Scaramuzzi, Baird, Boyle, Land & Wheeler, 1977;Louis, Parry, Robinson, Thorburn & Challis, 1977;Baird, 1978) and protein synthesis (Miller & Moore, 1976) are both influenced by ovarian steroid hormones. However, these changes have not been studied in relation to PG production in different tissues within the uterus, although it is well known that PGF-2a production (Scaramuzzi, Baird, Boyle, Land & Wheeler, 1977;Louis, Parry, Robinson, Thorburn & Challis, 1977;Baird, 1978) and protein synthesis (Miller & Moore, 1976) are both influenced by ovarian steroid hormones.…”

Section: Introductionmentioning

confidence: 99%

Protein, prostaglandin and steroid synthesis in caruncular and intercaruncular endometrium of sheep before implantation

Findlay¹,

Ackland²,

Burton³

et al. 1981

Reproduction

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The effect of the presence of a preimplantation embryo on protein concentration, rate of protein synthesis, beta-glucuronidase and acid phosphatase activities, steroid metabolism and prostaglandin F production in caruncular and intercaruncular tissue have been studied for sheep at Day 15 of pregnancy. The rate of protein synthesis in both tissues was greater in pregnant than in non-pregnant animals, although the difference was only significant in caruncular endometrium. The effect in caruncular tissue was mimicked in ovariectomized animals treated with oestradiol. Localized changes in the caruncular tissue were observed in respect of PGF with an increased tissue concentration, an enhanced basal release when the tissue was incubated in the presence of indomethacin, and a decreased net production. Maximum production of PGF in the 2 tissues was unaffected by the presence of an embryo but it was enhanced by oestradiol or progesterone treatment in intercaruncular tissue of ovariectomized ewes. beta-Glucuronidase and acid phosphatase activities and steroid metabolism were unaffected by pregnancy. However, in ovariectomized animals oestradiol treatment stimulated beta-glucuronidase activity in endometrium and myometrium. Progesterone treatment stimulated acid phosphatase activity in the intercaruncular endometrium. The results show that amongst several endometrial constituents investigated relatively few changes were detected by Day 15 post coitum, one day before definitive attachment. Those changes that did occur were associated with the dynamics of PGF production and the rate of protein synthesis, and were consistent with the production of a PGF binding component in caruncular endometrium which may be concerned with the protection of luteal function by redirection of uterine PGF production. Canonical variate analysis revealed that changes on Day 15 of pregnancy were mimicked most closely in caruncular tissue by treatment of ovariectomized ewes with oestradiol and progesterone, and in intercaruncular tissue by oestradiol treatment only.

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The secretion of prostaglandin F from the autotransplanted uterus of the ewe

Cited by 35 publications

References 10 publications

Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe

Effect of Immunization against Progesterone on Oestrus, Cycle Length, Ovulation Rate, Luteal Regression and LH Secretion in the Ewe

Prostaglandin Synthesis in the Endometrium of Women With Ovular Dysfunctional Uterine Bleeding

Protein, prostaglandin and steroid synthesis in caruncular and intercaruncular endometrium of sheep before implantation

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