scholarly journals Gonadotropin requirements for dominant follicle selection in GnRH agonist-treated cows

Reproduction ◽  
2004 ◽  
Vol 127 (6) ◽  
pp. 695-703 ◽  
Author(s):  
J H Hampton ◽  
J F Bader ◽  
W R Lamberson ◽  
M F Smith ◽  
R S Youngquist ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Gnrh Agonist ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Constant Infusion ◽  
Treatment Groups ◽  
Chain Cleavage ◽  
Hybridization Intensity ◽  
Development And Differentiation ◽  
Pre Treatment

A study was conducted to examine the effects of gonadotropins on ovarian follicular development and differentiation in GnRH agonist (GnRHa)-treated cattle. Holstein cows were allotted into two pre-treatment groups: controls (n = 5) and GnRHa-treated (n = 9). Ovaries were removed from control cows on day 5 following a synchronized estrus. Treatment with GnRHa resulted in follicular arrest at <5 mm. Following follicular arrest, GnRHa-treated cows received a constant infusion of FSH for 96 h (GnRHa/FSH), with a randomly selected subset receiving hourly pulses of LH in addition to FSH during the last 48 h of infusion (GnRHa/FSH + LH). At the end of infusion, ovaries were removed, follicles were counted and measured, and follicular fluid samples were collected from large follicles (>10 mm). Differences in expression of mRNA for LH receptor, FSH receptor, cytochrome P450 side-chain cleavage, 3β-hydroxysteroid dehydrogenase, cytochrome P450 17α-hydroxylase (P450c17) and cytochrome P450 aromatase were determined in large follicles using in situ hybridization. The number of large follicles did not differ between GnRHa/FSH-treated and GnRHa/FSH + LH-treated cows (P = 0.64), but was greater than control animals (P ≤ 0.004). Follicular fluid concentrations of estradiol-17β and androstenedione were highest in GnRHa/FSH + LH-treated cows (P ≤ 0.04), intermediate in control cows, and lowest in GnRHa/FSH-treated cows. Hybridization intensity of P450c17 was greater in GnRHa/FSH + LH-treated versus control or GnRHa/FSH-treated cows (P ≤ 0.03). These results indicate that while FSH can support bovine follicular growth >10 mm, LH increases androgen production and expression of P450c17.

scholarly journals Status of the down-regulated canine testis using two different GNRH agonist implants in comparison with the juvenile testis

Reproduction ◽  
2013 ◽  
Vol 146 (6) ◽  
pp. 517-526 ◽  
Author(s):  
S Goericke-Pesch ◽  
M Gentil ◽  
A Spang ◽  
M P Kowalewski ◽  
K Failing ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Gnrh Agonist ◽  
Sertoli Cells ◽  
Protein Level ◽  
Limit Of Detection ◽  
Mrna Level ◽  
Cell Nuclei ◽  
Chain Cleavage ◽  
Cleavage Enzyme

Testicular function in the dog was down-regulated using two different GNRH agonist implants, with adult and juvenile testes serving as controls. Treatment resulted in an increased percentage of the interstitial area and decreased area of Leydig cell nuclei. Expression of StAR and the steroidogenic enzymes cytochrome P450 side-chain cleavage enzyme (P450scc, CYP11A1) and cytochrome P450 17α-hydroxylase-17,20-lyase (P450c17, CYP17A1) in Leydig cells was blocked at the mRNA and protein level, showing no differences between the two agonists. Staining for androgen receptor (AR) by immunohistochemistry was positive in Sertoli, Leydig and peritubular cells and some spermatogonia, with in situ hybridization confirming expression in Sertoli cells. At the mRNA level, expression of AR was not affected; however, translation was blocked (reduced percentage of AR-positive Sertoli cells), with the number of nuclei in basal position being decreased. In the juvenile testes, mRNA expression of StAR, CYP11A1 and CYP17A1 was higher compared with the other groups but distinctly lower for the AR. At the protein level, the expression was at the limit of detection for StAR; AR-positive Sertoli cells were not detected. Our observations show that the down-regulated testis is different from the juvenile one rather resembling the testicular status in seasonal breeders out of season.

scholarly journals Cytochrome P450-Dependent Lipid Metabolism in Preovulatory Follicles

Endocrinology ◽  
2004 ◽  
Vol 145 (11) ◽  
pp. 5097-5105 ◽  
Author(s):  
J. W. Newman ◽  
J. E. Stok ◽  
J. D. Vidal ◽  
C. J. Corbin ◽  
Q. Huang ◽  
...  
Keyword(s):  
Cytochrome P450 ◽  
Lipid Metabolism ◽  
Follicular Fluid ◽  
Ovarian Tissue ◽  
Follicular Development ◽  
Epoxyeicosatrienoic Acid ◽  
Follicular Maturation ◽  
Before And After ◽  
Acid Metabolites

Abstract Estrogen biosynthesis and proteolysis are both important processes involved in ovarian follicular development, which may be influenced by cytochrome P450 (CYP)-dependent fatty acid metabolites. However, CYP-dependent lipid metabolism has not been characterized with respect to follicular maturation in vivo. Therefore, follicular fluid was collected in the hours before and after the LH surge in pigs, and concentrations of epoxy, hydroxy, and dihydroxy lipids were measured by liquid chromatography tandem mass spectrometry. Arachidonate oxidation and epoxyeicosatrienoic acid hydrolysis to dihydroxyeicosatrienoic acids (DHETs) were also assessed in thecal and granulosa tissue fractions, and the expression of CYP epoxygenases was evaluated by immunoblots using available antisera. To evaluate soluble epoxide hydrolase (sEH) expression, the porcine sEH was cloned from ovarian tissue, expressed and purified for antibody generation. The follicular fluid oxylipin concentrations ranged from 1–150 nm depending on the compound and estrous stage. The follicular fluid concentrations of CYP-dependent oxylipins increased at estrus, as did sEH expression; however, significant changes in epoxides were not observed, and the 11,12-DHET peak was delayed. The ratio of 14,15–DHET:11,12-DHET across all samples correlated with the log of follicular fluid estradiol concentrations (P &lt; 0.01). Epoxygenase activities were similar in theca and granulosa, varying little with follicular development, whereas the decline of a single CYP2J isoform at ovulation was observed by immunoblots. The sEH activity was higher in granulosa than in theca. Finally, the dynamic changes in follicular CYP-dependent arachidonic acid metabolites and their modulatory function in vascular models suggest roles for these metabolites in follicular maturation, which may include regulation of estradiol biosynthesis and preovulatory remodeling of the follicular wall that should be fully explored in future studies.

Treatment with bovine follicular fluid suppresses follicular development in gonadotrophin-releasing hormone-treated anoestrous ewes

1988 ◽  
Vol 119 (1) ◽  
pp. 95-100 ◽  
Author(s):  
M. G. Hunter ◽  
J. E. Hindle ◽  
B. J. McLeod ◽  
A. S. McNeilly
Keyword(s):  
Follicular Fluid ◽  
Follicular Development ◽  
Concurrent Administration ◽  
Releasing Hormone ◽  
Treatment Groups ◽  
Follicular Maturation ◽  
Testosterone Secretion ◽  
Gonadotrophin Releasing Hormone ◽  
The Mean

ABSTRACT The role of FSH in gonadotrophin-releasing hormone (GnRH)-induced follicular development in anoestrous ewes was investigated using injections of bovine follicular fluid (bFF) to reduce plasma FSH levels. Groups of five animals were treated for 12 h with GnRH (250 ng at 2-h intervals) alone, GnRH plus bFF or saline alone, or for 36 h with GnRH alone, GnRH plus bFF or bFF alone. The administration of bFF (1·5 ml s.c. at 8-h intervals) significantly (P<0·05) reduced mean plasma FSH levels, but with the exception of animals treated with bFF alone, had no effect on LH levels. Treatment with bFF alone for 36 h resulted in a significant (P<0·05) increase in LH concentrations. There was considerable variation in the number of follicles ≥2 mm in diameter in the treatment groups. The mean diameter, oestradiol secretion and number of 'oestrogenic' follicles were significantly (P<0·01) reduced in ewes treated with GnRH plus bFF or bFF alone for 36 h compared with those treated with GnRH alone. Testosterone secretion by the follicles was not affected by treatment. These results confirm previous findings that treatment with bFF decreases circulating FSH levels in anoestrous ewes and, moreover, that concurrent administration of bFF and GnRH inhibits the follicular maturation that is induced by treatment with GnRH alone, suggesting that FSH as well as LH is required for follicular maturation in the ewe. J. Endocr. (1988) 119, 95–100

Magnetic resonance image attributes of the bovine ovarian follicle antrum during development and regression

Reproduction ◽  
2000 ◽  
pp. 311-323 ◽  
Author(s):  
JL Hilton ◽  
GE Sarty ◽  
GP Adams ◽  
RA Pierson
Keyword(s):  
Magnetic Resonance ◽  
Relaxation Rate ◽  
Follicular Fluid ◽  
Magnetic Resonance Image ◽  
Follicular Development ◽  
Physiological Status ◽  
Proton Density ◽  
Dominant Follicle ◽  
Rate Heterogeneity ◽  
Pixel Value

The magnetic resonance images and maps of bovine ovaries acquired at defined phases of follicular development and regression were studied to determine whether magnetic resonance image attributes of the follicular antrum reflect the physiological status of dominant and subordinate ovarian follicles. Ovariectomies were performed at day 3 of wave one, day 6 of wave one, day 1 of wave two and at >/= day 17 after ovulation. The timings of ovariectomies were selected to acquire growing, early static, late static and regressing follicles of the first wave and preovulatory follicles of the ovulatory wave. Pre-selection and subordinate follicles were also available for analysis. Serum samples were taken on the day of ovariectomy and follicular fluid samples were taken after imaging. Numerical pixel value and pixel heterogeneity in a spot representing approximately 95% of the follicular antrum were quantified in T(1)- and T(2)-weighted images. T(1) and T(2) relaxation rates (T(1) and T(2)), proton density, apparent diffusion coefficients and their heterogeneities were determined from the computed magnetic resonance maps. The antra of early atretic dominant follicles showed higher T(2)-weighted mean pixel value (P < 0.008) and heterogeneity (P < 0. 01) and lower T(2) heterogeneity (P < 0.008) than growing follicles. Subordinate follicles in the presence of a preovulatory dominant follicle had higher T(1), T(1) heterogeneity, proton density, proton density heterogeneity, and lower mean pixel value in T(1)-weighted images than subordinate follicles of the anovulatory wave (P < 0.04). T(1) relaxation rate heterogeneity and proton density heterogeneity were positively correlated with follicular fluid oestradiol concentration (r = 0.4 and 0.3; P < 0.04). T(2) relaxation rate heterogeneity was positively correlated with follicular fluid progesterone concentration (r = 0.4; P < 0.008). Quantitative differences in magnetic resonance image attributes of the antrum observed among phases of follicular development and regression coincided with changes in the ability of the dominant follicle to produce steroid hormones and ovulate, and thus were indicative of physiological status and follicular health.

Studies on the mechanism of the selective suppression of plasma levels of follicle-stimulating hormone in the female rat after administration of steroid-free bovine follicular fluid

1983 ◽  
Vol 97 (3) ◽  
pp. 327-338 ◽  
Author(s):  
W. J. de Greef ◽  
F. H. de Jong ◽  
J. de Koning ◽  
J. Steenbergen ◽  
P. D. M. van der Vaart
Keyword(s):  
Follicular Fluid ◽  
Plasma Levels ◽  
Single Injection ◽  
Constant Infusion ◽  
Metabolic Clearance ◽  
Female Rat ◽  
Clearance Rates ◽  
Lh Rh ◽  
Lh Releasing Hormone ◽  
Hypophysial Portal

Steroid-free bovine follicular fluid (bFF) selectively suppresses the plasma levels of FSH in the female rat, demonstrating that bFF contains inhibin-like material. The present study was concerned with the effects of bFF on the hypothalamic release of LH releasing hormone (LH-RH) into hypophysial stalk blood and on the metabolic clearance rates of gonadotrophins. The metabolic clearance rates of FSH, LH and prolactin were determined after a single injection of and during a constant infusion with adenohypophysial extract. Similar results were obtained with both methods, and treatment with bFF did not alter the metabolic clearance rates of FSH, LH and prolactin. Anaesthesia with urethane, used for surgery involved in the collection of hypophysial stalk blood, did not interfere with the effect of bFF on plasma levels of FSH. The administration of bFF did not change the hypothalamic content of LH-RH, but caused a 30% decrease in the levels of LH-RH in hypophysial stalk plasma. However, a fraction isolated from bFF, which contained 20 times more inhibin-like activity per mg protein than bFF, did not alter the hypothalamic release of LH-RH into the hypophysial portal blood while this fraction was effective in specifically suppressing the plasma levels of FSH. It was concluded that the inhibin-like activity in bFF does not suppress the plasma levels of FSH by affecting its plasma clearance or by influencing the hypothalamic release of LH-RH, but that it has a direct effect on the adenohypophysis in inhibiting the release of FSH. Besides the inhibin-like activity, bFF also contains another factor which can decrease the levels of LH-RH in hypophysial stalk plasma.

Impact of different gonadotropin and GnRH agonist regimens on serum and follicular fluid hormone levels and folliculogenesis

1995 ◽  
Vol 9 (sup4) ◽  
pp. 7-12
Author(s):  
M. Filicori ◽  
G. E. Cognigni ◽  
A. Falbo ◽  
R. Amone ◽  
C. Pari ◽  
...  
Keyword(s):  
Gnrh Agonist ◽  
Follicular Fluid ◽  
Hormone Levels

Heart rate responses and plasma cortisol concentrations in ewes: comparison between cervical and laparoscopic intrauterine insemination and their associated handling procedures

1998 ◽  
Vol 66 (2) ◽  
pp. 383-387 ◽  
Author(s):  
M. Khalid ◽  
W. Haresign ◽  
D. G. Bradley
Keyword(s):  
Heart Rate ◽  
Stress Responses ◽  
Plasma Cortisol ◽  
Intrauterine Insemination ◽  
Management Practice ◽  
Treatment Groups ◽  
Cortisol Responses ◽  
The Mean ◽  
Pre Treatment ◽  
Mean Heart Rate

AbstractThis study consisted of two experiments. In experiment 1, stress responses of sheep which were restrained either in a laparoscopy cradle or a roll-over cradle were compared. The results of this experiment indicated that restraint in roll-over cradle is less (P < 0·05) stressful than that in a laparoscopy cradle when assessed in terms of the elevation and duration of both the mean heart rate and plasma cortisol responses. Experiment 2 compared the stress responses of sheep subjected to restraint in a laparoscopy cradle, restraint in a laparoscopy cradle with intrauterine artificial insemination (AI) by laparoscopy, minimal restraint with cervical AI or restraint in a roll-over cradle plus foot-trimming. All treatments resulted in significant elevations in both heart rate and plasma cortisol concentrations (F < 0·001). The peak heart rate was significantly (P < 0·05) higher in ewes subjected to cervical AI than in those subjected to intrauterine insemination, with other treatments intermediate. The peak cortisol response did not differ among different treatments. The duration over which both the mean heart rate and -plasma cortisol concentrations remained significantly elevated above pre-treatment concentrations did not differ among treatment groups. The results of this study suggest that while restraint using a laparoscopy cradle is more stressful than that using a rollover cradle, the stress inflicted by intrauterine insemination by laparoscopy itself is no greater than that due to restraint using the laparoscopy cradle alone, cervical AI or the management practice offoot-trimming using a rollover cradle.

Cytochrome P450 side-chain cleavage: Insights gained from homology modeling

2007 ◽  
Vol 265-266 ◽  
pp. 65-70 ◽  
Author(s):  
Karl-Heinz Storbeck ◽  
Pieter Swart ◽  
Amanda C. Swart
Keyword(s):  
Cytochrome P450 ◽  
Homology Modeling ◽  
Side Chain ◽  
Side Chain Cleavage ◽  
Chain Cleavage

scholarly journals Heat stress diminishes gonadotropin receptor expression and enhances susceptibility to apoptosis of rat granulosa cells

Reproduction ◽  
2005 ◽  
Vol 129 (4) ◽  
pp. 463-472 ◽  
Author(s):  
Takashi Shimizu ◽  
Izumi Ohshima ◽  
Manabu Ozawa ◽  
Satoko Takahashi ◽  
Atsushi Tajima ◽  
...  
Keyword(s):  
Heat Stress ◽  
Granulosa Cells ◽  
Follicular Fluid ◽  
Follicular Development ◽  
Receptor Expression ◽  
Female Rats ◽  
Aromatase Activity ◽  
Mrna Levels ◽  
Gonadotropin Receptor ◽  
Estradiol Levels

Heat stress inhibits ovarian follicular development in mammalian species. We hypothesized that heat stress inhibits the function of follicular granulosa cells and suppresses follicular development. To test this, immature female rats were injected with pregnant mare serum gonadotropin (PMSG) at 48 h after the start of temperature treatment (control: 25 °C, 50% RH; heat stress: 35 °C, 70% Relative Humidity). The ovaries and granulosa cells of follicles at different developmental stages were analyzed for gonadotropin receptor levels and aromatase activity; estradiol levels were measured in follicular fluid. Before injection, heat stress diminished only the amount of FSH receptor on granulosa cells of antral follicles. During PMSG-stimulated follicular development, heat stress strongly inhibited gonadotropin receptor levels and aromatase activity in granulosa cells, and estradiol levels in the follicular fluid of early antral, antral and preovulatory follicles. To examine apoptosis and mRNA levels of bcl-2 and bax in granulosa cells, follicles harvested 48 h after PMSG injection were cultured in serum-free conditions. Heat-stressed granulosa cells showed a time-dependent increase in apoptosis. The bcl-2 mRNA levels were similar in control and heat-stressed granulosa cells; bax mRNA levels were increased in heat-stressed granulosa cells. According to these results, heat stress inhibits expression of gonadotropin receptors in granulosa cells and attenuates estrogenic activity of growing follicles, granulosa cells of heat-stressed follicles are susceptible to apoptosis, and the bcl2/bax system is not associated with heat-stress-induced apoptosis of granulosa cells. Our study suggests that decreased numbers and function of granulosa cells may cause ovarian dysfunction in domestic animals in summer.

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