Reproductive Biology of PMSG-Primed Immature Female Rats12

Nuti, K. M.; Sridharan, B. N.; Meyer, Roland K.

doi:10.1095/biolreprod13.1.38

Cited by 33 publications

(14 citation statements)

References 25 publications

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“…we did not intend to induce superovulation. Gonadotropin-primed immature rats are fertile, and have normal gestational lengths and litter sizes [32]. We administered dexamethasone-21-phosphate disodium salt (DEX; ICN Biomedicals, Aurora, OH) dissolved in Dulbecco's phosphate-buffered saline (PBS, Gibco BRL, Gaithersburg, MD) at a dose of 1mg/kg given by intraperitoneal (i.p.)…”

Section: Animals and Treatmentsmentioning

confidence: 99%

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

Rockwell

Koos

2009

Journal of Reproduction and Development

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Abstract. Glucocorticoids have heterogeneous effects on reproductive function. We used a gonadotropin-primed, immature rat model to study the influence of dexamethasone (1 mg/kg), given during the latter stages of follicular development, on litter size, the number of oocytes released, and pituitary hormone levels. Dexamethasone-treated females released a larger number of oocytes at ovulation and gave birth to larger litters indicating the oocytes were viable. Survival to weaning age was not affected but average weight at weaning was lower for pups born to DEXtreated females. Serum FSH and LH were assayed at 12, 24 and 48 h following eCG and did not differ between dexamethasone-treated and control animals, but prolactin showed a prolonged pattern of elevation in DEX-treated females. Prolactin, which normally exhibits an elevation on proestrous, may modulate follicular development. Dexamethasone enhances fertility and fecundity possible through an effect of prolactin on follicle development, or by other direct effects on the ovary. These results may improve our understanding of the usefulness of DEX in assisted reproductive therapies for women. Key words: Fecundity, Glucocorticoids, Ovary (J. Reprod. Dev. 55: [247][248][249][250][251] 2009) eproductive function is often suppressed by the elevation of endogenous, or administration of exogenous, glucocorticoids. Anovulation and menstrual or estrous cycle disruptions can occur in conditions marked by adrenal hyperactivity (e.g. Cushing's Syndrome), or when women or animals experience chronic stimulation of the hypothalamic-pituitary-adrenal axis [1]. Glucocorticoidrelated reproductive suppression may involve disruption of central [1][2][3][4][5] and peripheral [6][7][8][9][10] functions of the reproductive axis as demonstrated by work in multiple species including rats [11][12][13], mice [14], sheep [15][16][17], humans [18,19] and other primates [7,20].The suppressive effect of glucocorticoids, however, is not universal. 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. restraint), presumably activating the endogenous hypothalamic-pituitary-adrenal axis, can enhance ovulation and increase fertility [26]. These stimulatory effects have been reported in rodent models, especially the rat, usually following treatment with dexamethasone (DEX) but triamcinolone acetonide, corticosterone and cortisol have also been used and some of these compounds give similar results [23,27]. Prior studies did not assess whether DEX-enhanced reproductive function also impacted fertility or offspring quality. The immature, gonadotropin-primed rat model is commonly used to assess follicular development, ovarian steroidogenesis, and ovulation. Because these ani...

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Section: Animals and Treatmentsmentioning

confidence: 99%

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

Rockwell

Koos

2009

Journal of Reproduction and Development

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“…Rats received an s.c. injection of 4 IU of pregnant mare's serum gonadotrophin (PMSG, Sigma, St Louis, MO, USA) in 0.2 ml of saline at 9:00 a.m. on day 27 of age to induce first oestrus and ovulation (Nuti et al, 1975). Rats were killed in a CO 2 inhalation chamber 72 h after the injection of PMSG, and the ovaries were collected, weighed and cultured as described below.…”

Section: Animalsmentioning

confidence: 99%

Nitric oxide reverses prostaglandin-induced inhibition in ovarian progesterone secretion in rats

Dong

Gangula

et al. 1999

Human Reproduction

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The present studies were undertaken to determine whether nitric oxide (NO) is involved in the regulation of ovarian progesterone and oestradiol secretion in rats. Immature female Sprague-Dawley rats at 27 days of age were injected s.c. with 4 IU pregnant mare's serum gonadotrophin (PMSG) and were killed 72 h after the injection. The ovaries were collected, weighed and cultured in Dulbecco's modified Eagle's medium containing saline, NO donor, NO synthesis inhibitor or prostaglandin F 2α (PGF 2α ). After 24 h culture, the medium concentrations of progesterone and oestradiol were measured by radioimmunoassay. Results showed that: (i) diethylenetriamine (DETA)/NO (1⍥10 -6 , 1⍥10 -5 , 1⍥10 -4 M), an NO donor, caused a dosedependent increase in progesterone synthesis (355 ⍨ 43, 443 ⍨ 46, 647 ⍨ 55 ng/g ovary respectively, P < 0.01) with a concomitant decrease in ovarian oestradiol secretion (408.1 ⍨ 50.7, 272.9 ⍨ 28.2, 132.6 ⍨ 34.6 pg/g ovary respectively, P < 0.01); (ii) neither progesterone nor oestradiol concentrations in the culture medium were altered by DETA without NO; (iii) N G -nitro-l-arginine methyl ester (1⍥10 -4 M), an inhibitor of NO synthesis, did not significantly affect progesterone and oestradiol secretion by rat ovaries; (iv) PGF 2α ( 1⍥10 -6 M) caused a fall in progesterone and oestradiol synthesis; (v) co-incubation with DETA/NO, significantly reversed the PGF 2α -induced decrease in progesterone concentrations from 184 ⍨ 29 to 388 ⍨ 60 ng/g (P < 0.01), but not that of oestradiol. It can be concluded that NO up-regulates progesterone secretion and down-regulates oestradiol secretion in rat ovaries, and NO can reverse PGF 2α -induced inhibition in ovarian progesterone secretion.

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“…Since the initial report [1], the immature rat treated with pregnant mare serum (PMS) followed by hCG has been used extensively as a model of follicular development [2], ovulation [3], pseudopregnancy [4], and pregnancy [5]. PMS injected into rodents has both FSH and LH activity; in comparison to ovine FSH it is twice as potent in the Steelman-Pohley bioassay, and in comparison to ovine LH it is half as potent in the ovarian ascorbic acid assay [6].…”

Section: Introductionmentioning

confidence: 99%

Autoradiographic Analysis of Follicle-Stimulating Hormone and Human Chorionic Gonadotropin Receptors in the Ovary of Immature Rats Treated with Equine Chorionic Gonadotropin1

Kishi

Greenwald

1999

Biology of Reproduction

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The gonadotropin-primed immature rat has become the most common model for the study of follicular development and ovulation. In this study, prepubertal female rats, 23 and 24 days old, were injected s. c. with 5 IU eCG, and ovaries were collected for topical autoradiography of FSH and hCG receptors at 48 or 24 h post-eCG, respectively (i.e., Day 25). In a baseline group, on Day 25 (before eCG), even the smallest preantral follicles with 1 layer of granulosa cells (GCs; primary follicles) possessed FSH receptors, but hCG receptors were found only on the theca of follicles with 2 or more layers of GCs. Human CG receptors were especially prominent in the interstitium that intimately surrounds preantral follicles without any distinction between theca and interstitial cells. There was a discrete theca surrounding antral follicles. Occasionally antral follicles had hCG receptors in the interstitium, but the adjacent theca was negative, suggesting that these follicles might be destined for atresia. By 24 h post-eCG, a now-discrete theca layer with hCG receptors surrounded all preantral follicles except for the primary follicles, which never responded to eCG. The interstitium was hypertrophied and epithelioid, as was the theca surrounding nonatretic preantral and antral follicles. Increased mitotic activity characterized the growing preantral follicle, and for the first time, FSH binding in GCs of antral follicles was greater than in the preantral population. By 48 h post-eCG, the primary follicles were still unresponsive to eCG. FSH receptors were even more pronounced in the GCs of large antral follicles, although hCG receptors were present in the GCs of only one third of the antral follicles, reflecting the small dose of eCG administered. By 48 h post-eCG, receptors in the interstitium were barely detectable. Using this model, the following study considers the functional in vitro changes in steroidogenesis in follicles from the smallest preantral follicles to the largest antral follicles.

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Reproductive Biology of PMSG-Primed Immature Female Rats12

Abstract: The reprodutive performance of PMSG-pnimed immature female rats (8 lU PMSG at 30 days of

Cited by 33 publications

References 25 publications

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

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

Nitric oxide reverses prostaglandin-induced inhibition in ovarian progesterone secretion in rats

Autoradiographic Analysis of Follicle-Stimulating Hormone and Human Chorionic Gonadotropin Receptors in the Ovary of Immature Rats Treated with Equine Chorionic Gonadotropin1

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