Anastomosis between Ovarian and Mesenteric Veins in Sheep: Induction of a Physiological Hyperstimulation of the Ovary

Garcés, D; Mariana, J. C.

doi:10.1006/jsre.1997.5161

Cited by 1 publication

(5 citation statements)

References 17 publications

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“…After anastomosis (AN), the steroids normally secreted by that ovary are catabolized by the liver. In the absence of the contralateral ovary, steroid levels in peripheral blood are close to those measured in a castrated animal (Garcès & Mariana 1997). A considerable advantage of the model is the ability to selectively prevent steroids secreted by the single AN ovary from reaching the hypothalamo-pituitary system, whilst the other ovary continues to function normally.…”

Section: Introductionmentioning

confidence: 72%

“…One or 2 days before or after surgery, all ewes (AN and SO groups) received 2·5 mg prostaglandin F 2 (PGF 2 ) i.m. (Estrumate; Ceutravet Plaucoet, France) to induce luteolysis (Garcès & Mariana 1997). In the AN group the left ovary was removed between 0 and 14 days after AN surgery and corpora lutea (CL) present on both ovaries were counted at this time.…”

Section: Experimental Designmentioning

confidence: 99%

“…1, additional samples were collected at 15 min intervals for 8 h on four separate days to assess pulsatile LH secretion. A single blood sample was collected from each hepatic and ovarian vein at the time of right ovary removal according to the procedure described by Garcès & Mariana (1997) for measurement of inhibin, oestradiol and progesterone levels. To assess the effect of the AN on the peripheral steroid levels, blood was collected 3 days after S0 or AN to measure progesterone levels and 2 days after PGF 2 to measure oestradiol levels.…”

Section: Experimental Designmentioning

confidence: 99%

“…The procedure used to anastomose the ovarian vein to the mesenteric vein is described in detail elsewhere (Garcès & Mariana 1997). The success of the procedure was assessed by measuring peripheral levels of progesterone from 5 to 9 days after surgery (Garcès & Mariana 1997).…”

Section: Surgical Techniquesmentioning

confidence: 99%

“…We recently developed an experimental model in the ewe in which most of the steroids secreted by one ovary are prevented from reaching the peripheral circulation (Garcès & Mariana 1997). The model involves anastomosing the ovarian vein to the portal hepatic vein through the mesenteric vein.…”

Section: Introductionmentioning

confidence: 99%

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Anastomosis of the ovarian vein to the hepatic portal vein in sheep induces ovarian hyperstimulation associated with increased LH pulsatility, but only in the absence of the contralateral ovary

Garcés¹,

Mariana²,

Blanc³

et al. 2000

Journal of Endocrinology

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In this study, two experiments were performed, the first of which examined the ovarian response in ewes that were subject to unilateral ovariectomy (ULO) at different intervals (0-14 days) after surgical anastomosis (AN) of the ovarian vein to the mesenteric vein (n=7 ewes), or sham operation (SO; n=4 ewes). Hypertrophy and development of multiple follicular and luteal structures on AN ovaries were observed after ULO, while SO ovaries remained of normal size and appearance after ULO. The second experiment involving 11 ewes (five AN; six SO) aimed to clarify the mechanism by which AN following ULO-induced ovarian hypertrophy and increased follicle development. The results confirmed that there were more large (>5 mm) follicles on AN compared with SO ovaries; however, their rate of atresia was similar. Oestradiol and progesterone concentrations in follicular fluid of class 1 follicles (5-9 mm) were higher in AN ovaries than those in control follicles of the same size collected in the late follicular phase of an induced oestrous cycle. In AN ewes, intrafollicular progesterone concentrations increased while follicular aromatase activity and intrafollicular oestradiol, inhibin A, follistatin and activin A concentrations all decreased as follicle size increased. Oestradiol and progesterone concentrations were substantially higher in ovarian venous blood than in hepatic venous blood, both in AN and SO ewes, whereas inhibin A levels were not significantly modified by passage through the liver in either group. Mean plasma LH concentration, and LH pulse frequency and amplitude increased markedly after AN but were not affected by SO. Plasma FSH showed only a small transient increase after AN, presumably due to the maintenance of inhibin feedback. Injection of prostaglandin F 2 4 days later did not further modify LH or FSH secretion in either group. Full ovariectomy (FO) 9-14 days after AN or SO increased LH secretion markedly in SO ewes but to a lesser degree in AN ewes; FO induced a large and rapid increase in FSH levels in both groups. In conclusion, AN of the ovary to the liver via the mesenteric vein provides a useful model for studying the feedback between the ovary and the hypothalamo-pituitary system and the mechanisms controlling follicle development. The present results indicate that the pattern of LH secretion is an important factor controlling the terminal phase of follicle development in the ewe.

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Section: Introductionmentioning

confidence: 72%

Section: Experimental Designmentioning

confidence: 99%

Section: Experimental Designmentioning

confidence: 99%

Section: Surgical Techniquesmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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