Paradoxical ovarian stimulations in the use of LHRH analogs

Noradrenaline modulates the presence of gonadotropin-releasing hormone in ovary. The importance of its interrelation on the ovarian steroidogenesis and apoptosis on dioestrus II in rat.

“…This finding is in agreement with Parinaud et al who have shown that the P 4 synthesis in ovary increased in the presence of LH in relation to the GnRH doses [18].…”

“…This decapeptide has been shown to have a stimulatory or an inhibitory effect on steroidogenesis [15,31,32]. The effects of GnRH might depend on various factors such as the hormonal environment of the ovary [18,20], the doses used [33,34], the type of receptor to which the decapeptide is bound [31,34,35], the down-regulation of the expression of the FSH and LH receptors [19] and the inhibitory effect on the steroidogenic enzymes [17,18,36,37].…”

“…In rat ovary, the presence of a protein called GnRH-like peptide has also been demonstrated, but this peptide is different from those found at the central nervous system level. Parinaud et al [18] found that GnRH and an agonist of its receptor exert direct inhibitory and stimulatory effects on the ovaries of several species. The inhibitory actions of GnRH or its agonist on gonad steroidogenesis involve the suppression of luteinizing hormone receptors or intermediary enzymes taking part in the steroidogenic pathway such as 3b-hydroxysteroid dehydrogenase (3b-HSD) [19].…”

Clinical and endocrine response to the withdrawal of gonadotropin-releasing hormone agonists during prolonged coasting

“…These effects appear dependent on the agonist dose as well as the stage of follicular maturation (9-13). Parinaud et al (23) found that during IVF treatment, flare protocols were more likely to stimulate E 2 production. This observation may be relevant to the high rate of cancellation due to high E 2 levels we observed with the flare protocol.…”

“…The GnRH receptors are present in various ovarian compartments including the granulosa, theca, interstitium, and corpus luteum (CL) (20). A significant literature based on data from experimental animals as well as clinical observations suggest that GnRHa may have stimulatory effects on the ovary including oocyte maturation (7), ovulation in hypophysectomized animals (7), steroidogenesis, follicular luteinization, and prostaglandin accumulation in experimental animals (7,10,21,22), steroidogenesis (23)(24)(25), ovarian hyperstimulation (26)(27)(28)(29), and cyst formation in women (30). These effects appear dependent on the agonist dose as well as the stage of follicular maturation (9-13).…”