Effects of Thermal Stress and Epinephrine on Uterine Blood Flow in Ewes

Roman-Ponce, H.; Thatcher, W.W.; Caton, Donald; Barron, Donald H.; Cj, Wilcox

doi:10.2527/jas1978.461167x

Cited by 27 publications

(5 citation statements)

References 26 publications

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“…Standard deviation never exceeded 4% of the mean for any animal. Flow transducers were calibrated in vitro before and after placement in each animal (Roman-Ponce, Thatcher, Caton, Barron & Wilcox, 1978).…”

Section: Chronic Experimentsmentioning

confidence: 99%

Adaptations to reduction of endometrial surface available for placental development in sheep

Caton¹,

Bazer²,

Kalra³

et al. 1984

Reproduction

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Summary. On Day 5 of pregnancy, before the blastocyst migrates to the uterus, one uterine horn was ligated to restrict the trophoblast to the lumen ipsilateral to the corpus luteum. The numbers of placentomes (caruncles and cotyledons) were reduced by half, but neither at 120 nor at 140 days of pregnancy (term 147 days) did the weights of placentae and fetuses of treated ewes differ significantly from those of control ewes. Amongst uterus-ligated animals prepared for chronic study, the rate of uterine blood flow (electromagnetic flow transducer, ml/min) to the pregnant horn was higher than in control ewes, as was the concentration of progestagens in maternal peripheral blood. There may be a compensatory response that causes hypertrophy of placentomes and that increases blood flow to the uterine horn containing placental tissue.

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Section: Chronic Experimentsmentioning

confidence: 99%

Adaptations to reduction of endometrial surface available for placental development in sheep

Caton¹,

Bazer²,

Kalra³

et al. 1984

Reproduction

Self Cite

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“…Alternatively, it is possible that heat stress acts at the ovarian level to reduce estradiol secretion indirectly by decreasing the ovarian blood flow. The uterine blood flow, which shares a common arterial blood supply in part with the ovary, has been shown to decrease in heat stressed ovariectomized ewes [33] and cows [34]. It seems of interest to determine by further study whether these factors are involved in the mechanism by which heat stress causes hypogonadism.…”

Section: Discussionmentioning

confidence: 99%

Hypogonadism in Heat Stressed Goats: Poor Responsiveness of the Ovary to the Pulsatile LH Stimulation Induced by Hourly Injections of a Small Dose of GnRH.

Kanai

Yagyu

Shimizu

1995

Journal of Reproduction and Development

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“…After implantation, it was observed that while respiratory movements affected celiac mean blood flow (MBF) slightly, visual observation confirmed that the probe and occluder did not alter vessel configuration. Blood flow probes were calibrated using an in vitro procedure similar to that described by Roman-Ponce et al (1978).…”

Section: Methodsmentioning

confidence: 99%

The Effect of High Ambient Temperature and Hypercapnia on Postprandial Intestinal Hyperemia in Domestic Cockerels

Bottje

Harrison

1986

Poultry Science

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Hubbard cockerels (2.8 to 3.6 kg) with chronically implanted electromagnetic blood flow probes placed on the celiac artery were used to determine the effect of elevated ambient temperature on postprandial intestinal hyperemia. Celiac mean blood flow (MBF) increased (P less than .05) from approximately 25 to 50 ml/min in response to feeding. When a thermoneutral temperature of 25 C was maintained, celiac MBF remained above 40 ml/min up to 210 min but fell below 25 ml/min by 300 min postprandial. In response to an acute heat exposure of 37 C, postprandial celiac MBF was reduced by approximately 50% in comparison to thermoneutral control values. Changes in celiac MBF during heat exposure were significantly (P less than .05) correlated (.60) with blood CO2 partial pressure (PCO2). To determine if flood PCO2 affected postprandial celiac MBF, cockerels were subjected to successive elevated ambient temperature and ambient CO2 treatments. Although cockerels exposed to 2.8% CO2 exhibited an increase in blood PCO2 regardless of temperature treatment, postprandial celiac MBF changes in these ambient CO2 experiments were only moderately correlated (P less than .05) with blood PCO2 (.34) but inversely correlated (-.83) with celiac vascular resistance (P less than .001). This study indicates that acute heat exposure reduces postprandial intestinal hyperemia and that this hemodynamic alteration was coincident with, but not necessarily dependent upon, changes in blood PCO2.

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Effects of Thermal Stress and Epinephrine on Uterine Blood Flow in Ewes

Cited by 27 publications

References 26 publications

Adaptations to reduction of endometrial surface available for placental development in sheep

Adaptations to reduction of endometrial surface available for placental development in sheep

Hypogonadism in Heat Stressed Goats: Poor Responsiveness of the Ovary to the Pulsatile LH Stimulation Induced by Hourly Injections of a Small Dose of GnRH.

The Effect of High Ambient Temperature and Hypercapnia on Postprandial Intestinal Hyperemia in Domestic Cockerels

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