Progestin Levels in Corpora Lutea and Progesterone in Ovarian Venous and Jugular Vein Blood Plasma of the Pregnant Bovine

Erb, R.E.; Estergreen, V.L.; Gomes, W. R.; Plotka, E. D.; Frost, O

doi:10.3168/jds.s0022-0302(68)86998-x

Cited by 46 publications

(22 citation statements)

References 37 publications

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“…This result correlates with findings of Silva and Costa [33], who indicated that the plasma P concentrations of pregnant heifers (by artificial insemination or embryo transfer) significantly deviate from those of nonpregnant and nonbred heifers on Day 17. On the other hand, no change in the tissue P concentrations could be observed between the CLs of the cyclic and pregnant cows, which is in agreement with a previous report [34]. Although luteal P appears to be produced to maintain early pregnancy during the mid-luteal phase in cyclic animals, there are some independent mechanisms between production of P within the CL and secretion of P into the circulation.…”

Section: Discussionsupporting

confidence: 81%

Vascular Changes in the Corpus Luteum During Early Pregnancy in the Cow

Beindorff

Nagai

Shirasuna

et al. 2010

Journal of Reproduction and Development

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Abstract. The present study determined vascular changes in the bovine corpus luteum (CL) at Day 16 (early maternal recognition period) and Day 40 in early pregnancy and compared them to the CL from Day 12 and Day 16 of the estrous cycle. The CLs were analyzed in the central and peripheral regions, where site-depending features of vessels and angiogenic factors are evident. The same protein level of the endothelial cell marker von Willebrand factor was retained in the CL from Day 16 of the estrous cycle to Day 40 of early pregnancy. The protein level of pericytes and smooth muscle cells was determined using smooth muscle α-actin; the level decreased at Day 40 of early pregnancy in both regions of the CL. No significant change in the expressions of vascular endothelial growth factors VEGF164 and VEGF120 mRNA occurred from Day 16 of the estrous cycle until Day 40 of early pregnancy. Angiopoietin (ANGPT)-2 / ANGPT-1 mRNA ratio (an index of instability of vasculature) increased in the periphery at Day 16 of the estrous cycle and then decreased until Day 40 of early pregnancy. The results suggest that there is no difference in vascular structure between non-pregnant and pregnant luteal tissue during the early maternal recognition period (Day 16). Also, luteal rescue by early pregnancy may be not associated with further blood vessel formation but rather may be related to the decrease of blood vessels per unit of area and blood vessel stabilization in the bovine CL. he corpus luteum (CL) is temporarily formed in the ovary following ovulation and secretes progesterone (P) to regulate the estrous cycle and to support the establishment of pregnancy. In cows, the CL begins to regress within 17-18 days after ovulation during the estrous cycle but retains a functional lifespan of more than 200 days during pregnancy [1]. Up to 40% of total embryonic loss occurs between Days 7 and 17 of pregnancy [2,3], which is a period associated with inadequate P concentrations. Thus, some changes of function and morphology in the CL to approve conception are critical during the estrous cycle, the early maternal recognition period and early pregnancy in the cow.Several distinct cell types, such as small and large luteal cells, vascular endothelial cells and pericytes, are distributed in the bovine CL [4]. More than 50% of cells in the mature CL are of vascular origin [4]. Alterations in luteal vascularity are associated with the luteinization and formation of the CL [5]. Angiogenesis is critical to development of the CL, as an inadequate microvasculature compromises luteal function [6]. The formation of a dense capillary network in the ovary enables the hormone-producing cells to obtain the oxygen, nutrients and also precursors necessary to synthesize and release different hormones essential for maintenance of the ovarian functions. Large luteal blood vessels, i.e., arteriolovenous vessels, have a smooth muscle cell layer and exist in the peripheral, but not central, region of the rabbit CL [7]. Indeed, in the bovine CL, the arteriolovenous ...

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Section: Discussionsupporting

confidence: 81%

Vascular Changes in the Corpus Luteum During Early Pregnancy in the Cow

Beindorff

Nagai

Shirasuna

et al. 2010

Journal of Reproduction and Development

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“…During the estrous cycle the plasma progesterone started to rise about the 4th day and this is in agreement with the observations of Stabenfeldt et al (1969) and Thorburn et al (1969) Stabenfeldt et al (1969) and Thorburn et al (1969 (1969) and Fylling (1970). Between the 100th day and just before lambing, however, the results obtained from the three ewes indicate that the progesterone concentration does not follow a smooth course as found by Bassett et al (1969) The overall pattern is very different from that found in the pregnant cow Erb et al 1968;Stabenfeldt et al 1970; Donaldson et al 1970;Robertson 1972) and goat (Heap and Linzell 1966) where the plasma progesterone concentration throughout pregnancy remains very similar to that observed at the peak of luteal activity during the cycle.…”

Section: Resultssupporting

confidence: 76%

Sequential Changes in Plasma Progesterone Levels in the Ewe During the Estrous Cycle, and During Pregnancy in Intact and Ovariectomized Sheep

Sarda¹,

Robertson²,

Smeaton³

1973

Can. J. Anim. Sci.

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“…Oophorectomy studies by McDonald et al (1953) and Erb et al (1968) have shown that removal of the ovary in 200-258 day pregnancies does not immediately terminate but usually shortens the gestation period. The interval to parturition was longest in cows oophorectomized at 200-210 days of gestation.…”

Section: Discussionmentioning

confidence: 98%

Bovine Plasma Oestrogens, Progesterone and Glucocorticoids During Dexamethasone Induced Parturition

Evans¹,

Wagner²

1976

Acta Endocrinologica

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Plasma samples were collected from jugular, uterine and utero-ovarian veins during glucocorticoid induced parturition. Plasma oestrogens, corticosteroids and progesterone were determined by competitive protein binding methods. Corticosteroids and progesterone began to decline within 8 to 10 h following DXMS treatment. Corticoids were only temporarily suppressed, while progesterone fell to minimum levels and remained low through calving. At this stage of gestation (270 days) peripheral plasma progesterone was primarily of ovarian origin. Pre-treatment with HCG appeared to support progesterone production by the CL despite DXMS treatment in 2 of 6 cows. These 2 cows failed to calve within the expected 96 h after DXMS. Plasma oestrogens did not show significant increases until 24 h after DXMS treatment. Cows which responded to DXMS treatment (calved) had significantly higher oestrogen levels than those which did not respond. It was concluded that oestrogens probably play a permissive rather than an initiating role in parturition.Parturition can be effectively induced in late gestation in the ewe (Bosc 1972) and cow (Adams 8c Wagner 1970) with appropriate doses of glucocorticoids. This has proven to be a useful tool in the study of physiological mechanisms controlling parturition, particularly the temporal changes in maternal or foetal plasma steroids at parturition.

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Progestin Levels in Corpora Lutea and Progesterone in Ovarian Venous and Jugular Vein Blood Plasma of the Pregnant Bovine

Cited by 46 publications

References 37 publications

Vascular Changes in the Corpus Luteum During Early Pregnancy in the Cow

Vascular Changes in the Corpus Luteum During Early Pregnancy in the Cow

Sequential Changes in Plasma Progesterone Levels in the Ewe During the Estrous Cycle, and During Pregnancy in Intact and Ovariectomized Sheep

Bovine Plasma Oestrogens, Progesterone and Glucocorticoids During Dexamethasone Induced Parturition

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