Ovulation and Ovum Maturation in the Rabbit Ovary Perfused in vitro

“…Although the details of the standard perfusion system have been modified over the years, the basic components have remained constant (22,23). The ovarian artery and vein were cannulated in situ after ligation of the major anastomotic connections, as previously described (21, 22).…”

Section: Methodsmentioning

confidence: 99%

Interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system in follicular growth and ovulation.

Yoshimura¹,

Aoki²,

Sueoka³

et al. 1996

J. Clin. Invest.

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The interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system (RAS) in follicular growth and ovulation were studied with the use of an isolated perfused rabbit ovary preparation. Ovulation failed to occur in either control ovaries or the experimental ovaries perfused with IGF-I in a concentration of 1, 10, or 100 ng/ml in the absence of gonadotropin. Exposure to IGF-I stimulated the secretion rate of angiotensin II-like immunoreactivity (Ang II-IR) in perfused rabbit ovaries in a dose-dependent manner. The percent increase in follicle diameter in ovaries perfused with IGF-I for 12 h was significantly correlated with the secretion rate of Ang II-IR at 12 h after exposure to IGF-I. The addition of IGFBP-3 to the perfusate did not induce ovulation in the absence of gonadotropin, but exposure to IGFBP-3 inhibited hCG-induced ovulation in a dosedependent manner. In addition, IGFBP-3 significantly reduced the ovarian secretion rate of Ang II-IR and prostaglandins stimulated by hCG administration. Intrafollicular plasminogen activator (PA) activity significantly increased within 4 h after exposure to 100 ng/ml of IGF-I, compared with that in control ovaries perfused with medium alone. The concomitant addition of IGFBP-3 to the perfusate significantly reduced the IGF-I-stimulated PA activity in the preovulatory follicles at 4, 6, and 8 h after exposure to IGF-I. However, IGFBP-3 alone affected neither the ovarian secretion rate of Ang II-IR nor intrafollicular PA activity. Exposure to streptokinase, an exogenous PA, in vitro stimulated both follicular growth and the intrafollicular Ang II-IR content. In conclusion, IGF-I enhances both ovarian Ang II production and follicular development by stimulating intrafollicular PA activity. ( J. Clin. Invest. 1996. 98:308-316.)

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“…Although the details of the standard perfusion system have been modified over the years, the basic components have remained constant ( 15 ). The ovarian artery and vein were cannulated in situ after ligation of the major anastomotic connections as previously described ( 16,17).…”

Section: Methodsmentioning

confidence: 99%

Gonadotropin stimulates ovarian renin-angiotensin system in the rabbit.

Yoshimura¹,

Koyama²,

Karube³

et al. 1994

J. Clin. Invest.

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The present study was undertaken to assess the role of ovarian renin-angiotensin system (RAS) in the preovulatory cascade induced by gonadotropin exposure. In the in vitro perfused rabbit ovaries, exposure to human chorionic gonadotropin (hCG) enhanced the secretion rate of angiotensin II (Ang II) within 1 h. The secretion rate reached maximal levels at 6 h and then declined thereafter. The intrafollicular Ang II content and renin-like activity were also significantly increased at 2 and 4 h after exposure to hCG, compared with control ovaries perfused with medium alone. The level of intrafollicular Ang II after hCG exposure significantly exceeded the concentration of Ang II in an equivalent volume of plasma. The addition of 1 ,uM captopril to the perfusate significantly inhibited the secretion rate of Ang II stimulated by hCG; however, captopril affected neither the ovulatory efficiency nor prostaglandin production in ovaries treated with hCG. Captopril significantly inhibited the resumption of meiosis in the ovulated ova and follicular oocytes stimulated by hCG. The administration of 100 ,ug Ang II at 2-h intervals to the perfusate reversed the inhibitory effects of captopril on hCG-induced oocyte maturation. In conclusion, these data indicate that gonadotropin stimulates renin-like activity and Ang11 production in the rabbit ovary. Ovarian renin-angiotensin system may play an important role in the process of oocyte maturation after exposure to gonadotropin. (J.

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Ovulation and Ovum Maturation in the Rabbit Ovary Perfused in vitro

Cited by 54 publications

References 0 publications

Effects of Varying Modes of Perfusion on Ovum Maturation and Ovulation in the Perfused Rabbit Ovary.

Effects of Varying Modes of Perfusion on Ovum Maturation and Ovulation in the Perfused Rabbit Ovary.

Interactions between insulin-like growth factor-I (IGF-I) and the renin-angiotensin system in follicular growth and ovulation.

Gonadotropin stimulates ovarian renin-angiotensin system in the rabbit.

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