Ovulations in Rat Ovaries Perfused in Vitro with Follicle-stimulating Hormone1

Abstract

Using the model of the isolated perfused rat ovary, we have found that highly purified ovine follicle-stimulating hormone (FSH) preparations cause ovulation and that this effect is not due to luteinizing hormone (LH) contamination. Ovine FSH-13 at a concentration of 1.5 mU/ml induced ovulations in all perfused ovaries (8.8 +/- 2.3 ovulations/ovary), as did a more purified preparation, ovine FSH-211B, at concentrations of 0.5 mU/ml (15.0 +/- 6.4 ovulations/ovary) and 5 mU/ml (11.3 +/- 2.6 ovulations/ovary). This ovulation-inducing effect of FSH is accompanied by a marked stimulation of estradiol levels in the perfusion medium without stimulation of progesterone levels. Furthermore, a purified rat FSH preparation (15 mU/ml) also induced ovulation in all ovaries (13.8 +/- 2.2 ovulations/ovary) as well as a stimulation of both estradiol and progesterone in the medium. These data clearly confirm the direct ovulatory effect of FSH on the ovary.

Pattern of ovarian steroid secretion during ovulation of in-vitro perfused rat ovaries varies with method of sampling

“…These steroid profiles in the perfusion fluid are similar to those of other perfusion studies with the rat ovary (Koos et al, 1984;Shaykh et al, 1985;Brännström et al, 1987a, b) and of the rabbit ovary Koos et al, 1983;Holmes et al, 1983Holmes et al, , 1985Holmes et al, , 1986Schmidt et al, 1986;Yoshimura et al, 1986Yoshimura et al, , 1987.…”

“…During the past decade, the in-vitro perfusion method has been used more and more to study the biochemical events of ovulation in rats and rabbits (Wallach et al, 1978;Janson et al, 1982;LeMaire et al, 1982;Holmes et al, 1983Holmes et al, , 1986Koos et al, 1984;Shaykh et al, 1985;Schmidt et al, 1986;Yoshimura et al, 1986Yoshimura et al, , 1987Yoshimura et al, , 1988Brännström et al, 1987a, b). In virtually all of these studies, ovarian steroids and/or prostaglandins (PG) were analysed by assaying samples of the circulating perfusion medium.…”

Characterization of an in vitro perfused rat ovary model: ovulation rate, oocyte maturation, steroidogenesis and influence of PMSG priming

“…However, the biochemical processes in the ovary occurring in between LH stimulation and follicular rupture are not fully understood. Using this model, several studies on the mechanism of ovulation have been performed, such as the influence of oestradiol (Koos et al 1984b), GnRH and FSH (Shaykh et al 1985, Sogn et al 1987 Critical aspects of these studies have been the influence of different agents on ovulation rate, ovulation time and steroidogenesis. perfusion of the isolated rabbit ovary were initially developed for short-term studies on the actions of gonadotrophins (Ahrin et al.…”

“…The reason for adopting the rat model was that the rat is one of the species most extensively studied in reproductive physiology. Using this model, several studies on the mechanism of ovulation have been performed, such as the influence of oestradiol (Koos et al 1984b), GnRH and FSH (Shaykh et al 1985, Sogn et al 1987 Critical aspects of these studies have been the influence of different agents on ovulation rate, ovulation time and steroidogenesis. Another important pre-ovulatory event which has not been studied in the rat model is the induction of oocyte maturation.…”