Ovarian and luteal blood flow, and peripheral plasma progesterone levels, in cyclic guinea-pigs

Hossain, Mohammed Iqbal; Lee, C. S.; Clarke, I. J.; O’Shea, J. D.

doi:10.1530/jrf.0.0570167

Cited by 51 publications

(31 citation statements)

References 27 publications

(30 reference statements)

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“…The within-assay c.v. was less than 20 % over the range 30--800 ng ml-I (eight assays). The between-assay c.v. of five assays for three plasma pools were 5'9% at 418 ng ml-I , 16'4% at 234ng ml-I and 25'8% at 81'2ng ml-I • Peripheral plasma progesterone was measured by the method of Hossain et al (1979). All the samples were measured in one assay and were within the range of 0·6-10·4 ng ml-I (c.v. <20%).…”

Section: Hormone Assaysmentioning

confidence: 99%

Plasma LH and FSH in Ewes That Were Either Fertile or Infertile After Long-Term Grazing of Oestrogenic Pasture

Rodgers

Clarke

Findlay

et al. 1980

Aust. Jnl. Of Bio. Sci.

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The levels of plasma LH and FSH were measured in serial blood samples taken at 15-min intervals for 6 h from ewes that had remained fertile after grazing oestrogenic pasture (clover-fertile ewes), from ewes that were permanently affected by clover disease (clover-infertile ewes) and from normal ewes. Two flocks of ewes from different locations were studied. In flock I, tonic LH secretion (total area under the curve of LH concentration versus time, 1 area unit = 1 ng ml-1 x 1 h) was significantly (P < 0'05) greater in clover-infertile ewes (10'4 area units) during anoestrus than in ewes that had remained fertile after prolonged grazing of oestrogenic clover (5·4 area units). Tonic LH and FSH secretions during the breeding season and FSH secretion during anoestrus were not significantly different. In flock 2, LH levels during the breeding season were significantly (P < 0'05) elevated in clover-infertile ewes (10' 9 area units) compared to normal ewes (5' 4 area units) that had never grazed oestrogenic clover. LH secretion in clover-infertile ewes (7. 8 area units) was intermediate to that found in infertile and control ewes. Concentrations of FSH, progesterone and ovarian vein oestradiol-17 P (Ez) during the breeding season were similar in the three groups.In another experiment, the positive feedback release of LH following administration of Ez (12'5,25 or 50 f.1g per ewe) was measured in anoestrous ewes of flock 2. Significantly (P < 0·01) more clover-infertile ewes demonstrated a positive feedback effect than control ewes when given 12· 5 f.1g Ez but not when given higher doses.The elevation of LH secretion in permanently affected clover-infertile ewes is consistent with the hypothesis that the hypothalamo-pituitary axis of these ewes is less responsive to the negative feedback effect of oestrogen. Furthermore, the patency of the positive feedback loop is consistent with the ability to ovulate.Other keywords: Clover disease. IntroductionLong-term grazing of oestrogenic clover pastures may cause permanent infertility in ewes (Bennetts et al. 1946;Barrett et al. 1965) although not all ewes grazing oestrogenic clover exhibit infertility. Infertile ewes have uterine endometrial hyperplasia and changes in cell type and function of the cervix (Adams 1976). In addition, there may be an associated neuroendocrine lesion. For example, Findlay et al. (1973) have reported that when infertile ewes which had previously grazed oestrogenic clover were ovariectomized, they were less likely to show elevated plasma LH levels, i.e. positive feedback (Goding et al. 1969), in response to oestradiol-17f1 (E 2 ) treatment than were normal ovariectomized ewes. This reduced responsiveness of the hypothalamo-pituitary axis to E2 could be related to changes in the number or affinity

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Section: Hormone Assaysmentioning

confidence: 99%

Plasma LH and FSH in Ewes That Were Either Fertile or Infertile After Long-Term Grazing of Oestrogenic Pasture

Rodgers

Clarke

Findlay

et al. 1980

Aust. Jnl. Of Bio. Sci.

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“…Thrombus formation during luteolysis does not resolve the controversy whether vascular constriction Pharriss et al 1970;Nett et al 1976) or functional changes in luteal cells (Behrman et al 1971;Baird 1974;Janson 1975;and Hossain et al 1979) appear first during luteolysis. In addition, the relevance of our findings to naturally occurring luteolysis in adult hamsters cannot be firmly established because immature ovaries have been treated by a high dose of gonadotrophins and a high multiple does rate of exogenous PGF2a-Further experiments with adult animals are necessary to investigate the applicability of our observations.…”

Section: Discussionmentioning

confidence: 99%

“…One group of authors claims that PGF 2a causes vasoconstriction of ovarian vessels, thus affecting luteal cells indirectly via a reduced blood flow Pharriss et al 1970; Nett et al 1976). Another group favours the idea that PGF2a induces biochemical alterations directly at the luteal cell level (Behrman et al 1971;Baird 1974;Janson 1975; Hossain et al 1979). The morphological course of luteolysis is attributed to auto-and heterophagocytosis in sheep and guinea pigs (Bjersing et al 1970;McClellan et al 1977;Paavola 1977Paavola , 1979.…”

Section: Introductionmentioning

confidence: 99%

Luteolysis and Thrombus Formation in Ovaries of Immature Superstimulated Golden Hamsters

Spanel‐Borowski¹,

Heiss²

1986

Aust. Jnl. Of Bio. Sci.

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Thrombus appearance during luteolysis with and without exogenous prostaglandin (PGF2a) was studied in immature golden hamsters between days 4 and 7 after stimulation with pregnant mares' serum gonadotrophin (PMSG) followed by human chorionic gonadotrophin. Both ovaries were weighed and cut in series for light-microscopic evaluation. The fibrinolytic activity was determined by the fibrin slide .method after treatment with PGF2a on day 4 after PMSG stimulation and compared with controls of days 3 and 4 after PMSG stimulation.There was a marked decrease in ovarian weights in the experimental and the control group between days 4 and 7 after PMSG. Few necrotic cells were seen in corpora lutea on day 5, but many on day 6. All of them had disappeared on day 7. The number of ovaries with thrombi was 80-100% in both groups on day 4 and declined to approximately zero levels on day 7. The amount of thrombus formation appeared to be higher in the PGF2a-treated groups than in controls. Fibrinolytic activity was high in controls on day 3 and low in controls and in PGF2a-treated animals on day 4 after PMSG. It is concluded that (i) thrombus formation occurs in superstimulated ovaries during luteolysis; and (ii) thrombus formation is related to a decrease in fibrinolytic activity.

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“…In the regressive corpus luteum, blood flow decreases during luteolysis [2,3], and we can also observe a dramatic reduction in the number of the luteal vessels [4]. It has been shown that luteal vascular development is coincident with growth and regression of the corpus luteum [5].…”

mentioning

confidence: 99%

“…PGF2a or its analog causes a rapid and dramatic decrease in luteal blood flow and deletion of the luteal vessel [3,4]. Azmi et al [4] reported that the decline in luteal blood flow made endothelial cells of the luteal vessel disappear.…”

mentioning

confidence: 99%

Effects of TN F-.ALPHA. Injection into the Ovarian Parenchyma on Luteal Blood Vessels in Rabbits.

et al. 1995

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Abstract. It has been reported that tumor necrosis factor-a (TNF-a) derived from luteal macrophage is concerned with luteolysis.In the present study, to evaluate the correlation between TNF-a and regression of luteal blood vessels, recombinant human TNF-a (rh-TNF) was injected into the parenchyma of pseudopregnant rabbit ovaries. These injections were performed on day 7 of pseudopregnancy (functional luteal phase). Only Mg++ and Ca++ free phosphate buffer saline (PBS-) as the solvent was injected in the control group. Estimations of conditions in the luteal vessels after the injections was performed by observations of luteal vascular corrosion casts under a scanning electron microscope. Concentrations of serum progesterone before or after the injection were also assayed. In the control group, no change in the structure of luteal vessels was observed after PBS-injection, but regressing blood vessels with strictures, obstructions and rugged surfaces on the vessels were observed, and also concentrations of serum progesterone decreased noticeably after rh-TNF injection. These findings suggest that TNF-a plays a role in angiolysis through luteolysis in the rabbit corpus luteum.

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Ovarian and luteal blood flow, and peripheral plasma progesterone levels, in cyclic guinea-pigs

Cited by 51 publications

References 27 publications

Plasma LH and FSH in Ewes That Were Either Fertile or Infertile After Long-Term Grazing of Oestrogenic Pasture

Plasma LH and FSH in Ewes That Were Either Fertile or Infertile After Long-Term Grazing of Oestrogenic Pasture

Luteolysis and Thrombus Formation in Ovaries of Immature Superstimulated Golden Hamsters

Effects of TN F-.ALPHA. Injection into the Ovarian Parenchyma on Luteal Blood Vessels in Rabbits.

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