Effect of actinomycin D on uterine prostaglandin production and oestrous cycle length in guinea-pigs

Nl, Poyser

doi:10.1530/jrf.0.0560559

Cited by 24 publications

(13 citation statements)

References 13 publications

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“…These effects take some hours to develop, and are inhibited by protein synthesis inhibitors [25,40]. By contrast, the vasorelaxant effect of 17βE # is not thought to be dependent on the nuclear oestrogen receptor ; its speed of onset (a few minutes) is too rapid, and it is not blocked by protein synthesis inhibitors [12].…”

Section: Discussionmentioning

confidence: 99%

Comparable vasorelaxant effects of 17α- and 17β-oestradiol on rat mesenteric resistance arteries: an action independent of the oestrogen receptor

et al. 1999

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17beta-Oestradiol (17betaE(2)) has vasorelaxant properties that may contribute to its beneficial cardiovascular effects. The mechanism of vasorelaxation remains controversial, but does not appear to involve interaction of 17betaE(2) with its nuclear receptor. The present study examined the effects on resistance arteries of 17betaE(2) and its isomer, 17alpha-oestradiol (17alphaE(2)), which does not bind to the classical oestrogen receptor. In arteries precontracted with either noradrenaline or KCl, 17betaE(2) and 17alphaE(2) caused comparable relaxation in a concentration-dependent manner over the concentration range 0.1-10 micromol/l, with no significant difference in the maximal effect obtained. Pre-incubation of the arteries with 17betaE(2) or 17alphaE(2) for 15 min reduced the magnitude and duration of the force generated with both noradrenaline and KCl to a comparable degree. Vasorelaxation induced by either 17betaE(2) or 17alphaE(2) was not blocked by an inhibitor of NO synthase or by protein synthesis inhibitors, indicating that vasodilatation is not dependent upon either NO generation or protein synthesis. In the absence of extracellular calcium, both oestradiols still relaxed arteries precontracted with NA, suggesting that they inhibit intracellular calcium release. Both 17betaE(2) and 17alphaE(2) therefore have important and comparable vasorelaxant properties that do not require interaction with the nuclear oestrogen receptor. Direct interactions with the cell membrane or with ion-channel proteins may be responsible.

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Section: Discussionmentioning

confidence: 99%

Comparable vasorelaxant effects of 17α- and 17β-oestradiol on rat mesenteric resistance arteries: an action independent of the oestrogen receptor

et al. 1999

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“…Endometrial prostaglandin (PG) F-2a synthesis in guinea-pigs is dependent upon increased protein synthesis (Poyser, 1979;Riley & Poyser, 1989). The findings from these and other studies indicate that oestradiol, acting on a progesterone-primed uterus, stimulates the synthesis of a protein which activates phospholipase (PL) A-2, by either mobilizing calcium or interacting synergistically with calcium.…”

Section: Introductionmentioning

confidence: 83%

Effect of melittin on prostaglandin production by guinea-pig uterus

Johnson¹,

Poyser²

1991

Reproduction

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Summary. Melittin, an activator of phospholipase (PL) A-2, increased the outputs of prostaglandin (PG) F-2\g=a\and 6-keto-PGF-1\g=a\, but not of PGE-2, from Day-7 guineapig uterus superfused in vitro. Reducing the extracellular calcium concentration (by omitting calcium chloride from the superfusing fluid) partially inhibited the stimulatory effect of melittin on uterine PG production. (an intracellular calcium antagonist) completely prevented the stimulation of PGF-2\g=a\and 6-keto-PGF-1\g=a\ output by melittin, although the production of both PGs tended to increase after stopping the melittin and TMB-8 treatments. TMB-8 also inhibited the increases in outputs of PGF\x=req-\ 2\g=a\,6-keto-PGF-1\g=a\ and PGE-2 and prevented contraction of the uterus induced by exogenous PLA-2. Trifluoperazine (a calmodulin antagonist) had no inhibitory effect on the increases in outputs of PGF-2\g=a\and 6-keto-PGF-1\g=a\ produced by melittin; it potentiated the stimulatory effect of melittin on 6-keto-PGF-1\g=a\ output and allowed melittin to increase PGE-2 output. When melittin was applied twice to the superfused uterus with an interval of 1 h between each treatment, partial refractoriness of the responses to melittin was seen: the magnitudes of the increases in PGF-2\g=a\and 6\ x =r eq-\ keto-PGF-1\g=a\ outputs were 40\p=n-\50%less after the second treatment than after the first treatment. These results show that melittin stimulates the synthesis of PGF-2\g=a\and PGI-2 (measured as 6-keto-PGF-1\g=a\) in guinea-pig uterus by mechanisms which are calcium dependent. The results are compatible with there being a protein of similar functional activity to melittin in the guinea-pig uterus, which may be involved in the stimulation of endometrial PGF-2\g=a\ synthesis.

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“…However, Poyser (1979) andPoyser et al (1987) have presented some contradictory evidence in this respect in the guineapig, but in turn this prostanoid contributes to the induction of oestrogen-induced uterine growth, presumed to be genomically mediated. This train of events may be of significance in other hormonally regulated tissues.…”

Section: Discussionmentioning

confidence: 99%

The effects of thromboxane receptor antagonists on oestrogen‐induced uterotrophic responses in the spontaneously hypertensive rat

Kerr

Marshall

Senior

1991

British J Pharmacology

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1 The possible role of thromboxane in the uterotrophic response to oestrogen, in the spontaneously hypertensive rat was investigated by use of the thromboxane receptor antagonists EP092, AH23848 and BM 13.505.2 The parameters studied were uterine blood flow (measured by the microsphere technique), uterine wet and dry weights and the concentrations of cytosolic and nuclear oestrogen receptors. 3 The antagonists attenuated oestradiol-induced uterine blood flow and significantly reduced both wet and dry uterine weight. These changes were accompanied by decreases in nuclear oestrogen receptor levels. 4 The results suggest a supportive role for thromboxane in oestradiol-induced uterine growth.

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Effect of actinomycin D on uterine prostaglandin production and oestrous cycle length in guinea-pigs

Cited by 24 publications

References 13 publications

Comparable vasorelaxant effects of 17α- and 17β-oestradiol on rat mesenteric resistance arteries: an action independent of the oestrogen receptor

Comparable vasorelaxant effects of 17α- and 17β-oestradiol on rat mesenteric resistance arteries: an action independent of the oestrogen receptor

Effect of melittin on prostaglandin production by guinea-pig uterus

The effects of thromboxane receptor antagonists on oestrogen‐induced uterotrophic responses in the spontaneously hypertensive rat

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