Clomiphene citrate inhibits gonadotropin-induced ovulation by reducing cyclic adenosine 3′,5′-cyclic monophosphate and prostaglandin E₂ levels in rat ovary

Objective

To determine whether clomiphene citrate (CC) inhibited gonadotropin-induced ovulation by reducing cyclic adenosine 3′,5′-cyclic monophosphate (cAMP) and prostaglandin E₂ (PGE₂) levels in ovary. If so, to determine whether E₂ coadministration could protect against these effects of CC.

Design

A controlled prospective study.

Setting

Laboratory research setting in the department of reproductive biomedicine at a national research institute in India.

Animal(s)

Sixty sexually immature female rats that were 24–25 days of age.

Intervention(s)

The sexually immature female rats were given a single injection (10 IU IM) of pregnant mare serum gonadotropin. After 48 hours, the rats were given single injections of hCG (10 IU) along with CC, with or without E₂, for 16 hours.

Main Outcome Measure(s)

Number of superovulated COCs, ovary and uterus weight, FSH and LH levels in serum, and cAMP and PGE₂ levels in ovary.

Result(s)

The superovulatory dose of gonadotropins significantly increased ovary and uterus weights, cAMP and PGE₂ levels in ovary, and serum levels of FSH and LH. Coadministration of CC (10 mg/kg body weight) significantly reduced levels of cAMP, PGE₂ in the ovary, ovary and uterus weights, and ovulation rate, whereas FSH and LH levels were not significantly altered. Supplementation of E₂ protected against these inhibitory effects of CC and augmented levels of FSH and LH in serum.

Conclusion(s)

Clomiphene citrate inhibited gonadotropin-induced ovulation by reducing cAMP and PGE₂ levels in the ovary, and E₂ protected against these effects of CC on gonadotropin-induced ovulation in rat.

Key Words:  Clomiphene citrate , ovulation , ovary and uterus weights , PGE₂ , cAMP , E₂ , FSH , LH