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Correlation between steroids and plasmin in rat ovaries during ovulatory process
C K Dhanju1, S K Dhanoa, S S Guraya
1Zoology Department, College of Basic Sciences & Humanities, Punjab Agricultural University, Ludhiana, India.
Indian Journal of Experimental Biology
|August 1, 1991
Summary
Steroid hormones like progesterone and estradiol-17 beta significantly increase ovarian plasmin activity during ovulation in rats. Tamoxifen, an estrogen antagonist, inhibits this activity, revealing a positive steroid-ovarian plasmin relationship.
Area of Science:
- Reproductive biology
- Endocrinology
- Molecular mechanisms of ovulation
Background:
- Ovulation is a critical reproductive event regulated by complex hormonal and enzymatic processes.
- Ovarian plasmin, a key enzyme, is implicated in ovulation, but its precise regulation by steroid hormones requires further elucidation.
Purpose of the Study:
- To investigate the effect of progesterone and estradiol-17 beta on ovarian plasmin activity during ovulation.
- To determine the influence of tamoxifen, a nonsteroidal estrogen antagonist, on ovarian plasmin activity in relation to ovulation.
Main Methods:
- Adult female albino rats were administered progesterone and estradiol-17 beta via intramuscular injection.
- Ovarian plasmin activity was quantified using the fibrin plate method at precise intervals around ovulation.
- Ovulation timing was confirmed by serial measurements of ovarian plasmin activity.
Main Results:
- Progesterone and estradiol-17 beta significantly enhanced ovarian plasmin activity at the time of ovulation (2:30 a.m.).
- Ovarian plasmin activity exhibited a surge towards ovulation, peaking at 2:30 a.m., and subsequently declined.
- Tamoxifen treatment resulted in inhibitory effects on ovarian plasmin activity compared to controls and estradiol-17 beta treated groups.
Conclusions:
- Steroid hormones, specifically progesterone and estradiol-17 beta, play a crucial role in upregulating ovarian plasmin activity during ovulation.
- A positive correlation exists between steroid hormone levels and ovarian plasmin activity, suggesting hormonal control over this enzymatic process.
- Estrogen antagonism via tamoxifen demonstrates the involvement of estrogenic pathways in modulating ovarian plasmin activity during the ovulatory period.