Progesterone ensures full-length luteal phases during the breeding season in ewes

1991 ◽  
Vol 129 (3) ◽  
pp. 371-379 ◽  
Author(s):  
S. J. Legan ◽  
H. I'Anson ◽  
P. Neiser
Keyword(s):  
Serum Concentration ◽  
Breeding Season ◽  
Gnrh Agonist ◽  
Luteal Phase ◽  
Full Length ◽  
Serum Concentrations ◽  
Phase Increment ◽  
End Of Treatment ◽  
Prostaglandin F ◽  
Gonadotrophin Releasing Hormone

ABSTRACT To test the hypothesis that each luteal-phase increase in the serum concentration of progesterone throughout the breeding season prevents a short luteal phase in the next cycle, 22 ewes were treated with an i.v. injection of 10 μg gonadotrophin-releasing hormone (GnRH) agonist every 12 h for 33 days beginning on day 12 of a cycle synchronized with prostaglandin F2α. Six days after the last injection of GnRH agonist, ten of the ewes were treated s.c. for 14 days with progesterone-containing silicone elastomer implants to generate luteal-phase serum concentrations. Twenty ewes stopped cycling during GnRH agonist treatment and 16 of these, eight controls and eight treated with progesterone, resumed cycling after the end of treatment. In the control ewes, oestrous cycles began 25·0±7·5 (s.e.m.) days after the end of GnRH agonist administration, a short luteal phase preceding initiation of cycles in six ewes. In contrast, all eight progesterone-treated ewes resumed cycling synchronously 22·0 ±0·2 days after the end of GnRH agonist treatment and all began with full-length luteal phases. These results support the hypothesis that each luteal-phase increment in the serum concentration of progesterone throughout the breeding season prevents a short luteal phase in the next cycle. Journal of Endocrinology (1991) 129, 371–379

Regulation of gonadotrophin-releasing hormone receptor mRNA expression in the sheep

1994 ◽  
Vol 143 (1) ◽  
pp. 175-182 ◽  
Author(s):  
J Brooks ◽  
A S McNeilly
Keyword(s):  
Gnrh Agonist ◽  
Hormone Receptor ◽  
Luteal Phase ◽  
Gnrh Antagonist ◽  
Single Injection ◽  
Mrna Levels ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone ◽  
Oestradiol Production

Abstract To investigate the regulation of the sheep gonadotrophin-releasing hormone receptor (GnRH-R) gene expression, two different treatment regimes were used. Experiment 1 examined the effects of twice daily injections of ovine follicular fluid (oFF, 15 ml s.c.) as a source of inhibin, and daily GnRH antagonist injections (Nal-Glu.HOAc, 2 mg s.c.) on days 9–12 of the oestrous cycle. Luteolysis was induced on day 12 with prostaglandin (PG) and the ewes killed at two different stages; day 12 (luteal) and 18 h after PG injection. Experiment 2 examined the effect of a single injection of oestradiol benzoate (100 μg i.m.) 18 h before death in luteal phase ewes and ewes chronically implanted with the GnRH agonist, buserelin. In both experiments, pituitaries were removed at death for determination of pituitary GnRH binding, LH content and levels of GnRH-R and LHβ mRNA. In addition in experiment 1, follicles ≥2·5 mm were dissected from the ovaries for determination of oestradiol content. In experiment 1, oFF treatment during the luteal phase completely inhibited follicle oestradiol production but was without effect on the other parameters measured. After cessation of oFF treatment and induction of luteolysis, a significant (P<0·05) increase in plasma LH occurred but the normal follicular increase in both GnRH-R mRNA levels and GnRH binding seen in control ewes was prevented. GnRH antagonist treatment alone or in combination with oFF also inhibited follicle oestradiol production, prevented the increase in GnRH-R mRNA, completely inhibited GnRH binding and significantly decreased LHβ mRNA levels. Pituitary LH content was unaffected by any treatment. In experiment 2, oestradiol treatment did not affect GnRH-R mRNA levels, GnRH binding, LHβ mRNA or pituitary LH content in luteal phase ewes, whilst chronic GnRH agonist treatment acted to decrease these parameters dramatically. A single injection of oestradiol in the GnRH agonist treated ewes significantly (P<0·05) increased GnRH-R mRNA levels and completely restored GnRH binding to luteal levels, without any effect on LHβ mRNA or pituitary LH content. These results suggest that the control of GnRH receptor expression in the sheep is directly related to oestradiol and not to the action of GnRH itself. Journal of Endocrinology (1994) 143, 175–182

Effect of gonadotrophin-releasing hormone agonist-induced suppression of LH and FSH on follicle growth and corpus luteum function in the ewe

1987 ◽  
Vol 115 (2) ◽  
pp. 273-282 ◽  
Author(s):  
A. S. McNeilly ◽  
H. M. Fraser
Keyword(s):  
Continuous Infusion ◽  
Corpus Luteum ◽  
Gnrh Agonist ◽  
Luteal Phase ◽  
Plasma Concentrations ◽  
Follicular Development ◽  
Similar Proportion ◽  
Simple Method ◽  
Releasing Hormone ◽  
Gonadotrophin Releasing Hormone

ABSTRACT Continuous infusion of a gonadotrophin-releasing hormone (GnRH) agonist (buserelin) by osmotic minipump from day 1 of the luteal phase in five Welsh ewes resulted in a sustained suppression of plasma concentrations of FSH which increased three- to eightfold within 2 days after the end of infusion 29 days later. Plasma concentrations of LH increased three- to eightfold over the first 5 days of infusion and then became basal and non-pulsatile until 1 day after the end of infusion. Duration of the luteal phase and plasma concentrations of progesterone were not significantly different in control and treated ewes. Pulses of LH in control ewes were followed by increases in concentrations of progesterone in samples collected at 10-min intervals for 7 h on days 10 and 14 of the luteal phase. However, progesterone was also released in a pulsatile manner in the absence of LH pulses in both control and GnRH agonist-treated ewes. After natural luteolysis, no ovulation or corpus luteum function occurred in treated ewes up to 15 days after the end of treatment on day 29, even though oestrus, indicating follicular development and oestrogen secretion, had occurred 8–11 days after treatment ended. After 30 days of infusion the ovaries of GnRH agonist-treated ewes contained no follicles > 2·5 mm in diameter. In follicles of 1–2 mm in diameter the basal and LH-stimulated production of oestradiol and testosterone in vitro were similar in both control and GnRH agonist-treated ewes, and a similar proportion of these follicles was oestrogenic (> 370 mol oestradiol per follicle) in GnRH agonist-treated and control ewes. These results show (1) that progesterone secretion by the corpus luteum of the ewe can be sustained in the presence of basal concentrations but absence of pulsatile secretion of LH, and progesterone is released in a pulsatile manner whether or not LH pulses are present, (2) that follicular development beyond 2·5 mm in diameter in the ewe is dependent upon adequate stimulation by both LH and FSH and (3) that the continuous infusion of GnRH agonist is a simple method for providing reproducible suppression of LH and FSH and follicular development in the ewe to allow the study of gonadotrophin action on the ovary in vivo. J. Endocr. (1987) 115, 273–282

Specific binding sites for gonadotrophin-releasing hormone, LH/chorionic gonadotrophin, low-density lipoprotein, prolactin and FSH in homogenates of human corpus luteum. II: Concentrations throughout the luteal phase of the menstrual cycle and early pregnancy

1987 ◽  
Vol 113 (2) ◽  
pp. 317-327 ◽  
Author(s):  
T. A. Bramley ◽  
D. Stirling ◽  
I. A. Swanston ◽  
G. S. Menzies ◽  
A. S. McNeilly ◽  
...  
Keyword(s):  
Menstrual Cycle ◽  
Corpus Luteum ◽  
Gnrh Agonist ◽  
Luteal Phase ◽  
Specific Binding ◽  
Low Density Lipoprotein ◽  
Density Lipoprotein ◽  
Corpora Lutea ◽  
Agonist Binding ◽  
Gonadotrophin Releasing Hormone

ABSTRACT Corpora lutea were obtained from 52 women undergoing laparotomy during the luteal phase of the menstrual cycle. In addition, stromal, thecal and granulosa cell preparations were obtained from seven women undergoing ovariectomy during the late follicular–preovulatory phase of the cycle. The specific binding of a 125I-labelled gonadotrophin-releasing hormone (GnRH) agonist [d-Ser(But)6] GnRH(1–9)-ethylamide (buserelin) and of human chorionic gonadotrophin (hCG), human FSH (hFSH), human prolactin (hPRL) and human low-density lipoprotein (hLDL) to tissue homogenates was measured under optimal conditions. Bound LH/hCG was estimated by elution with acid-citrate buffer, followed by radioimmunoassay of released hormone. Binding of GnRH agonist, though variable, was highest in mid-luteal corpus luteum and high binding was also present in three out of four corpora lutea of pregnancy. Binding of LH/hCG increased significantly with luteinization, reaching maximal levels in the mid-luteal phase before falling significantly. Occupancy of LH receptors by bound LH was relatively constant throughout the luteal phase (10·7–35·3%), but occupancy increased to >90% in corpora lutea from early pregnancy. Binding of hFSH was variable, with only five out of 50 corpora lutea having binding greater than 10 pg/μg DNA. Similarly, hPRL binding varied markedly with only six out of 44 having binding greater than 50 pg/μg DNA. Binding of LDL was highest in the early- to mid-luteal phases of the cycle. In corpora lutea from all stages of the menstrual cycle (excluding corpora albicantia), GnRH agonist binding was highly correlated with the levels of unoccupied and occupied LH receptors (P < 0·001; n = 49 and n = 48 respectively) and with LDL receptors (P< 0·002; n = 49). Binding of GnRH agonist was also correlated with PRL binding (P<0·05; n = 21) but not with FSH receptors (P>0·4; n = 25). In addition, LDL binding was associated with PRL (P< 0·005; n = 21) and FSH receptors (P<0·05; n = 25) and with endogenously bound LH (P<0·03; n = 48), but not with unoccupied LH receptors (P = 0·8; n = 49). Moreover, in corpora lutea from the mid-luteal phase, there was a strong association between GnRH agonist binding and LDL receptors (P<0·02; n = 23). The correlations between GnRH agonist binding and a number of important indices of luteal function suggest a physiological role for GnRH-like factors in the human corpus luteum. J. Endocr. (1987) 113, 317–327

Control of the koala (Phascolarctos cinereus) anterior pituitary-gonadal axis with analogues of GnRH

2008 ◽  
Vol 20 (5) ◽  
pp. 598 ◽  
Author(s):  
Camryn D. Allen ◽  
Michelle Burridge ◽  
Mandy L. Chafer ◽  
Vere N. Nicolson ◽  
Sophia C. Jago ◽  
...  
Keyword(s):  
Gnrh Agonist ◽  
Anterior Pituitary ◽  
Luteal Phase ◽  
Gnrh Antagonist ◽  
Cell Function ◽  
Phascolarctos Cinereus ◽  
Natural Sequence ◽  
Dose Rates ◽  
Anterior Pituitary Function ◽  
Gonadotrophin Releasing Hormone

The aim of the present study was to determine whether analogues of gonadotrophin-releasing hormone (GnRH) could be used to both induce an acute testosterone response and suppress anterior pituitary function in male koalas, and induce a luteal phase in female koalas. Experiment 1 characterised the steroidogenic response of male koalas to administration of 30 μg (4.3 μg kg–1) natural-sequence GnRH. Intra-muscular injection of natural-sequence GnRH induced the release of LH and testosterone with peak concentrations at 30 min (3.7 ± 1.9 ng mL–1) and 2 h (5.4 ± 0.5 ng mL–1), respectively. In Experiment 2, a single injection of the GnRH antagonist acyline (100 μg (14.3 μg kg–1) or 500 μg (71.4 μg kg–1)) did not influence the testosterone response to subsequent injections of natural-sequence GnRH. In Experiment 3, 4 μg (~0.67 μg kg–1) of the GnRH agonist buserelin induced a luteal phase in five female koalas based on a LH surge, secretion of progestogen, and a normal-length oestrous cycle. The findings have shown that (1) natural-sequence GnRH can be used to test gonadotroph cell function and determine the testosterone-secreting capacity of male koalas, (2) the GnRH antagonist, acyline, at the dose rates used, does not suppress the pituitary-testis axis in male koalas, and (3) the GnRH agonist, buserelin, induces a normal luteal phase in female koalas.

Serum Concentration and Skin Expression of S100A7 (Psoriasin) in Patients Suffering from Hidradenitis Suppurativa

Dermatology ◽  
2020 ◽  
pp. 1-7
Author(s):  
Aleksandra Batycka-Baran ◽  
Wojciech Baran ◽  
Danuta Nowicka-Suszko ◽  
Maria Koziol-Gałczyńska ◽  
Andrzej Bieniek ◽  
...  
Keyword(s):  
Serum Concentration ◽  
Hidradenitis Suppurativa ◽  
Protein Concentration ◽  
Normal Skin ◽  
Innate Immune ◽  
Antimicrobial Protein ◽  
Healthy Controls ◽  
Serum Concentrations ◽  
Reactive Protein

<b><i>Background:</i></b> Hidradenitis suppurativa (HS) is a chronic inflammatory skin disease. An important role of innate immune dysregulation in the pathogenesis of HS has been highlighted. S100A7 (psoriasin) is an innate, antimicrobial protein that exerts proinflammatory and chemotactic action. <b><i>Objectives:</i></b> The objective of the study was to investigate serum concentrations of S100A7 in individuals with HS as compared to healthy controls. Further, we evaluated the expression of S100A7 in lesional HS skin as compared to perilesional (clinically uninvolved) HS skin and normal skin. <b><i>Methods:</i></b> Serum concentrations of S100A7 were evaluated with a commercially available ELISA kit. The expression of S100A7 in the skin was assessed using qRT-PCR and immunofluorescence staining. <b><i>Results:</i></b> We found increased expression of S100A7 in lesional HS skin as compared to perilesional HS skin (<i>p</i> = 0.0017). The expression of S100A7 in lesional HS skin was positively associated with serum C-reactive protein concentration and the severity of disease according to Hurley staging. The serum concentration of S100A7 in individuals with HS was decreased as compared to healthy controls and patients with psoriasis. <b><i>Conclusions:</i></b> Upregulated in lesional HS skin, S100A7 may enhance the inflammatory process and contribute to the HS pathogenesis.

scholarly journals CG is more effective than the GnRH agonist buserelin for inducing the first ovulation of the breeding season in mares

2021 ◽  
Author(s):  
Diana Fanelli ◽  
Matteo Tesi ◽  
Alessandra Rota ◽  
Massimiliano Beltramo ◽  
Giuseppe Conte ◽  
...  
Keyword(s):  
Breeding Season ◽  
Gnrh Agonist

scholarly journals Luteal Support with very Low Daily Dose of Human Chorionic Gonadotropin after Fresh Embryo Transfer as an Alternative to Cycle Segmentation for High Responders Patients Undergoing Gonadotropin-Releasing Hormone Agonist-Triggered IVF

2021 ◽  
Vol 14 (3) ◽  
pp. 228
Author(s):  
Andrea Roberto Carosso ◽  
Stefano Canosa ◽  
Gianluca Gennarelli ◽  
Marta Sestero ◽  
Bernadette Evangelisti ◽  
...  
Keyword(s):  
Embryo Transfer ◽  
Chorionic Gonadotropin ◽  
Gnrh Agonist ◽  
Human Chorionic Gonadotropin ◽  
Luteal Phase ◽  
Real Life ◽  
Luteal Support ◽  
Gnrh Agonist Trigger ◽  
High Responders ◽  
Agonist Trigger

The segmentation of the in vitro fertilization (IVF) cycle, consisting of the freezing of all embryos and the postponement of embryo transfer (ET), has become popular in recent years, with the main purpose of preventing ovarian hyperstimulation syndrome (OHSS) in patients with high response to controlled ovarian stimulation (COS). Indeed cycle segmentation (CS), especially when coupled to a GnRH-agonist trigger, was shown to reduce the incidence of OHSS in high-risk patients. However, CS increases the economic costs and the work amount for IVF laboratories. An alternative strategy is to perform a fresh ET in association with intensive luteal phase pharmacological support, able to overcome the negative effects of the GnRH-agonist trigger on the luteal phase and on endometrial receptivity. In order to compare these two strategies, we performed a retrospective, real-life cohort study including 240 non-polycystic ovarian syndrome (PCO) women with expected high responsiveness to COS (AMH >2.5 ng/mL), who received either fresh ET plus 100 IU daily human chorionic gonadotropin (hCG) as luteal support (FRESH group, n = 133), or cycle segmentation with freezing of all embryos and postponed ET (CS group, n = 107). The primary outcomes were: implantation rate (IR), live birth rate (LBR) after the first ET, and incidence of OHSS. Overall, significantly higher IR and LBR were observed in the CS group than in the FRESH group (42.9% vs. 27.8%, p < 0.05 and 32.7% vs. 19.5%, p < 0.05, respectively); the superiority of CS strategy was particularly evident when 16–19 oocytes were retrieved (LBR 42.2% vs. 9.5%, p = 0.01). Mild OHSS appeared with the same incidence in the two groups, whereas moderate and severe OHSS forms were observed only in the FRESH group (1.5% and 0.8%, respectively). In conclusion, in non-PCO women, high responders submitted to COS with the GnRH-antagonist protocol and GnRH-agonist trigger, CS strategy was associated with higher IR and LBR than the strategy including fresh ET followed by luteal phase support with a low daily hCG dose. CS appears to be advisable, especially when >15 oocytes are retrieved.

Effect of Long-Acting Thyroid Stimulator on Serum Concentration of Luteinizing Hormone in the Rat

1975 ◽  
Vol 48 (3) ◽  
pp. 231-233
Author(s):  
P. Dandona ◽  
D. J. El Kabir ◽  
F. Naftolin ◽  
P. C. B. MacKinnon
Keyword(s):  
Luteinizing Hormone ◽  
Serum Concentration ◽  
Pituitary Gland ◽  
Immunoglobulin G ◽  
Adrenocorticotrophic Hormone ◽  
Serum Concentrations ◽  
Serum Luteinizing Hormone ◽  
Serum Lh ◽  
Long Acting ◽  
Dexamethasone Suppression

1. The effect of long-acting thyroid stimulator (LATS) on the serum luteinizing hormone (LH) levels of the rat in pro-oestrus has been studied. 2. The injection of three out of four LATS-containing immunoglobulin G fractions caused an increase in amounts of serum LH. 3. Adrenalectomy and dexamethasone suppression did not alter this response. 4. Injection of large doses of adrenocorticotrophic hormone did not produce any increase in serum concentrations of LH. 5. It is postulated that LATS may have a direct effect on the release of LH from the pituitary gland.

Suppression of pituitary-testis function in rats treated neonatally with a gonadotrophin-releasing hormone agonist and antagonist: acute and long-term effects

1989 ◽  
Vol 123 (1) ◽  
pp. 83-91 ◽  
Author(s):  
K.-L. Kolho ◽  
I. Huhtaniemi
Keyword(s):  
Body Weight ◽  
Gnrh Agonist ◽  
Gnrh Antagonist ◽  
Long Term Effects ◽  
Adult Rats ◽  
Releasing Hormone ◽  
Serum Lh ◽  
Accessory Sex Organs ◽  
Gonadotrophin Releasing Hormone

ABSTRACT The acute and long-term effects of pituitary-testis suppression with a gonadotrophin-releasing hormone (GnRH) agonist, d-Ser(But)6des-Gly10-GnRH N-ethylamide (buserelin; 0·02, 0·1, 1·0 or 10 mg/kg body weight per day s.c.) or antagonist, N-Ac-d-Nal(2)1,d-p-Cl-Phe2,d-Trp3,d-hArg(Et2)6,d-Ala10-GnRH (RS 68439; 2 mg/kg body weight per day s.c.) were studied in male rats treated on days 1–15 of life. The animals were killed on day 16 (acute effects) or as adults (130–160 days; long-term effects). Acutely, the lowest dose of the agonist decreased pituitary FSH content and testicular LH receptors, but with increasing doses pituitary and serum LH concentrations, intratesticular testosterone content and weights of testes were also suppressed (P< 0·05–0·01). No decrease was found in serum FSH or in weights of accessory sex organs even with the highest dose of the agonist, the latter finding indicating continuing secretion of androgens. The GnRH antagonist treatment suppressed pituitary LH and FSH contents and serum LH (P< 0·05–0·01) but, as with the agonist, serum FSH remained unaltered. Testicular testosterone and testis weights were decreased (P <0·01) but testicular LH receptors remained unchanged. Moreover, the seminal vesicle and ventral prostate weights were reduced, in contrast to the effects of the agonists. Pituitary LH and FSH contents had recovered in all adult rats treated neonatally with agonist and there was no effect on serum LH and testosterone concentrations or on fertility. In contrast, in adult rats treated neonatally with antagonist, weights of testis and accessory sex organs remained decreased (P <0·01–0·05) but hormone secretion from the pituitary and testis had returned to normal except that serum FSH was increased by 80% (P <0·01). Interestingly, 90% of the antagonist-treated animals were infertile. It is concluded that treatment with a GnRH agonist during the neonatal period does not have a chronic effect on pituitary-gonadal function. In contrast, GnRH antagonist treatment neonatally permanently inhibits the development of the testis and accessory sex organs and results in infertility. Interestingly, despite the decline of pituitary FSH neonatally, neither of the GnRH analogues was able to suppress serum FSH values and this differs from the concomitant changes in LH and from the effects of similar treatments in adult rats. Journal of Endocrinology (1989) 123, 83–91

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