Effects of dexamethasone on ovarian activity in rats

Abstract

Rats with 5-day ovarian cycles were treated with dexamethasone (0.025 to 0.4 mg per rat per day) to examine its effects on ovarian activity. All doses of dexamethasone markedly suppressed endogenous secretion of ACTH as evidenced by decrease in weight of the adrenal glands after 7-23 days of treatment. Treatment with 0.4 mg of dexamethasone from the day of ovulation appeared to induce pseudopregnancy in more than 90% of the rats studied: pseudopregnancies lasted for 14-22 days. Induction of pseudopregnancy occurred less, in a dose-dependent fashion, when the lower doses of dexamethasone were administered.However, prolonged treatment with these lower doses resulted also in pseudopregnancy albeit after 1 or more cycles of 5 to 7 days. The effects of large doses of glucocorticoids on ovarian activity in rats, and possibly in humans as well, may be mediated predominantly through a stimulatory action of such drugs on prolactin secretion. Treatment with 0.4 mg per day of dexamethasone from the day before pro-oestrus did not interfere with ovulation and pseudopregnancy ensued this ovulation in all rats studied. Occasionally, unexpectedly large numbers of eggs per ovulating animal were found during treatment with dexamethasone. The data indicate failure of large doses of dexamethasone to interfere with ovulation and, possibly, induction of an increase in numbers of maturing follicles: this latter action deserves further analysis.

Dexamethasone Enhances Fertility and Preovulatory Serum Prolactin Levels in eCG/hCG Primed Immature Rats

“…These data are consistent with previous reports that DEX [22,25] and triamcinolone acetonide, another synthetic glucocorticoid, can enhance ovulation [27]. We further demonstrated that DEX treatment yielded a 1½ to 2-fold increase in litter size.…”

“…This regimen normally results in ovulation around midnight of experiment day 3. The number of follicles that mature and release oocytes under this eCG/hCG dosage protocol is similar to normally cycling rats [11,12,22], i.e. we did not intend to induce superovulation.…”

“…Synthetic corticoids variably stimulate the release of pituitary hormones, follicle stimulating hormone (FSH), luteinizing hormone (LH) and prolactin (PRL) [21], enhance FSH action in the follicular phase of the cycle [10], and may accelerate the timing of ovulation and increase the number of oocytes released [22][23][24][25]. In addition, acute exposure to stressful stimuli (e.g.…”

Chronic Effects of the Novel Glucocorticosteroid RPR 106541 Administered to Beagle Dogs by Inhalation

“…X70. trous cycle, were also consistent with effects described for synthetic glucocorticosteroids in the dog (23). Inhibition of ovulation due to glucocorticosteroid-induced suppression of luteinizing hormone (LH) release (ie, preovulatory LH surge) has been described for rodents and women (4,12,13,38). Inhibition of the preovulatory LH surge in female rabbits has also been demonstrated with medroxyprogesterone acetate (31).…”

Effect of Endogenous Faecal Glucocorticoid Metabolites on Reproduction in Wild Pigs - A Non Invasive Approach

“…As TPA is thought to play an important role in ovulation, this effect could have important physiological relevance. This finding may also explain that dexamethasone treatment on proestrus, in some cases resulted in an unexpectedly large number of eggs per ovulating animal [17,18]. …”