Effects of melatonin on the production of GnRH and LH in luteal cells of pregnant sows

2021 ◽  
Author(s):  
Wenlong Zhang ◽  
Dewen Tong ◽  
Zelin Zhang ◽  
Jiang Peng ◽  
Sitian Yang ◽  
...  
Keyword(s):  
Luteinizing Hormone ◽  
Receptor Antagonist ◽  
Mrna Expression ◽  
Potential Role ◽  
Gonadotropin Releasing Hormone ◽  
Membrane Receptors ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Luteal Cells ◽  
Lh Secretion

Effects of melatonin on the release and synthesis of gonadotropin releasing hormone (GnRH) and luteinizing hormone (LH) at the hypothalamus and pituitary levels have been explored in some species, but a similar study in the corpora lutea (CL) has not yet been conducted. In this study, the immunostaining for GnRH and LH was observed in luteal cells of porcine CL during pregnancy, and a significant effect of pregnant stage on the level of GnRH and LH was found; higher values for GnRH and LH immunostaining and mRNA were detected in the early- and mid- stages CL than in the later-stage CL (P < 0.01). Furthermore, the patterns of melatonin membrane receptors (MT1 and MT2) expression were consistent with those of GnRH and LH expression in the CL of pregnant sows; the relative levels of MT1 and MT2 in the early- and mid- stages were significantly higher than those in the later-stage (P < 0.01). In luteal cells, melatonin dose-dependently increased in GnRH and LH secretion and mRNA expression. Melatonin also increased the GnRH–induced accumulation of LH, and the LH–induced secretion of P4 in luteal cells. Additionally, the effects of melatonin on luteal GnRH and LH production, were blocked by luzindole, a nonselective MT1 and MT2 receptor antagonist. Our results demonstrate the stimulatory effects of melatonin on GnRH and LH production in luteal cells of pregnant sows, suggesting a potential role for melatonin in luteal function through regulating the release and synthesis of GnRH and LH in luteal cells.

scholarly journals Induction of final oocyte maturation in Cyprinidae fish by hypothalamic factors: a review

2009 ◽  
Vol 54 (No. 3) ◽  
pp. 97-110 ◽  
Author(s):  
P. Podhorec ◽  
J. Kouril
Keyword(s):  
Luteinizing Hormone ◽  
Oocyte Maturation ◽  
Hormone Secretion ◽  
Inhibitory Effect ◽  
Gonadotropin Releasing Hormone ◽  
Luteinizing Hormone Secretion ◽  
Releasing Hormone ◽  
Final Oocyte Maturation ◽  
In Captivity ◽  
Lh Secretion

Gonadotropin-releasing hormone in Cyprinidae as in other Vertebrates functions as a brain signal which stimulates the secretion of luteinizing hormone from the pituitary gland. Two forms of gonadotropin-releasing hormone have been identified in cyprinids, chicken gonadotropin-releasing hormone II and salmon gonadotropin-releasing hormone. Hypohysiotropic functions are fulfilled mainly by salmon gonadotropin-releasing hormone. The only known factor having an inhibitory effect on LH secretion in the family Cyprinidae is dopamine. Most cyprinids reared under controlled conditions exhibit signs of reproductive dysfunction, which is manifested in the failure to undergo final oocyte maturation and ovulation. In captivity a disruption of endogenous gonadotropin-releasing hormone stimulation occurs and sequentially that of luteinizing hormone, which is indispensible for the final phases of gametogenesis. In addition to methods based on the application of exogenous gonadotropins, the usage of a method functioning on the basis of hypothalamic control of final oocyte maturation and ovulation has become popular recently. The replacement of natural gonadotropin-releasing hormones with chemically synthesized gonadotropin-releasing hormone analogues characterized by amino acid substitutions at positions sensitive to enzymatic degradation has resulted in a centuple increase in the effectiveness of luteinizing hormone secretion induction. Combining gonadotropin-releasing hormone analogues with Dopamine inhibitory factors have made it possible to develop an extremely effective agent, which is necessary for the successful artificial reproduction of cyprinids.

scholarly journals Galanin Enhancement of Gonadotropin-Releasing Hormone-Stimulated Luteinizing Hormone Secretion in Female Rats Is Estrogen Dependent

Endocrinology ◽  
2003 ◽  
Vol 144 (2) ◽  
pp. 484-490 ◽  
Author(s):  
Cynthia L. Splett ◽  
Joseph R. Scheffen ◽  
Joshua A. Desotelle ◽  
Vicky Plamann ◽  
Angela C. Bauer-Dantoin
Keyword(s):  
Luteinizing Hormone ◽  
Hormone Secretion ◽  
Gonadotropin Releasing Hormone ◽  
Gonadal Steroids ◽  
Female Rats ◽  
Luteinizing Hormone Secretion ◽  
Ovx Rats ◽  
Lh Secretion ◽  
Lines Of Evidence

The hypothalamic peptide GnRH is the primary neuroendocrine signal regulating pituitary LH in females. The neuropeptide galanin is cosecreted with GnRH from hypothalamic neurons, and in vitro studies have demonstrated that galanin can act at the level of the pituitary to directly stimulate LH secretion and also augment GnRH-stimulated LH secretion. Several lines of evidence have suggested that the hypophysiotropic effects of galanin are important for the generation of preovulatory LH surges. To determine whether the pituitary actions of galanin are enhanced by the preovulatory steroidal milieu, LH responses to galanin administration (with or without GnRH) were examined in: 1) ovariectomized (OVX); 2) OVX, estrogen (E)-primed; and 3) OVX, E- and progesterone-treated female rats. Results from the study indicate that galanin enhances GnRH-stimulated LH secretion only in the presence of E (in OVX, E-primed, or E- and progesterone-treated rats). Galanin alone does not directly stimulate LH secretion under any of the steroid conditions examined. In the absence of gonadal steroids (OVX rats), galanin inhibits GnRH-stimulated LH secretion. These findings suggest that the primary pituitary effect of galanin is to modulate GnRH-stimulated LH secretion, and that the potentiating effects of galanin occur only in the presence of E.

Hypothesis testing of the aging male gonadal axis via a biomathematical construct

2001 ◽  
Vol 280 (6) ◽  
pp. R1755-R1771 ◽  
Author(s):  
Daniel M. Keenan ◽  
Johannes D. Veldhuis
Keyword(s):  
Luteinizing Hormone ◽  
Gonadotropin Releasing Hormone ◽  
Computer Assisted ◽  
Aging Male ◽  
Aging Men ◽  
Model Predictions ◽  
Feedback Networks ◽  
Lh Secretion ◽  
Appl Math ◽  
Dynamic Ensembles

Neuroendocrine axes are feedback- and feedforward-coupled dynamic ensembles. Disruption of selected pathways in such networklike organizations may explicate loss of orderly hormonal output as observed in aging. To test this notion more explicitly, we implemented an earlier computer-assisted biomathematical model of the interlinked male hypothalamo [gonadotropin-releasing hormone (GnRH)]-pituitary [luteinizing hormone, (LH)]-testicular [Leydig cell testosterone (Te)] axis ( Am J Physiol Endocrinol Metab Physiol 275: E157–E176, 1988; Keenan D., W. Sun, and J. D. Veldhuis, SIAM J Appl Math 61: 934–965, 2000). Thereby, we appraise mechanistic hypotheses for more disorderly LH and Te secretion in aging men. We compare model predictions with monitored abnormalities in the older male, namely, irregular patterns of individual and synchronous LH and Te release, reduced 24-h rhythmic Te output, and variably elevated LH secretion. Among the mechanisms examined, the most parsimonious aging hypothesis would entail impaired LH feedforward on Te without or with attenuated Te feedback on GnRH/LH secretion. This investigative strategy should aid in exploring new postulates of disrupted feedback networks in pathophysiology.

Regulation of luteal function by luteinizing hormone and prolactin at different times of the luteal phase

1995 ◽  
Vol 133 (6) ◽  
pp. 701-717 ◽  
Author(s):  
Bernd Hinney ◽  
Christina Henze ◽  
Wolfgang Wuttke
Keyword(s):  
Luteinizing Hormone ◽  
Luteal Phase ◽  
Serum Testosterone ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Autonomous Regulation ◽  
Progesterone Secretion ◽  
Estradiol Secretion ◽  
Late Luteal Phase ◽  
Ovulatory Period

Hinney B, Henze C, Wuttke W. Regulation of luteal function by luteinizing hormone and prolactin at different times of the luteal phase. Eur J Endocrinol 1995;133:701–17. ISSN 0804–4643 In 54 healthy women luteal function was assessed by sequential withdrawals of blood samples at 10-min intervals for 8–10 h. Subgroups of the women were studied during the early and late ovulatory period and during the early, mid- and late luteal phase. Bio- and immunoreactive luteinizing hormone (LH), prolactin, testosterone, estradiol and progesterone levels were determined in each sample. While the bio- and immunoreactivity of LH pulses correlated fairly well, a number of bio- or immunoreactive LH pulses were observed that were not detected by the respective other method. Responsivity of the corpus luteum to LH episodes developed during the second half of the luteal phase and was most marked in cases where LH episodes were accompanied by prolactin episodes. In the absence of prolactin episodes, LH episodes did not stimulate progesterone or estradiol secretion. The highest incidence of coincident LH and prolactin pulses was observed during the mid- and late luteal phase. Serum testosterone levels showed also some fluctuations but these were independent of immuno- or bioactive LH episodes and therefore most likely not of luteal origin. Prior to menstruation LH episodes were not any more stimulatory to progesterone secretion, indicating that it is not the withdrawal of LH but, rather, another possibly intraovarian mechanism that results in luteolysis. In a number of women, increased estradiol and progesterone secretion was strictly related to the prior occurrence of LH and prolactin pulses. In other subjects, both gonadal steroids fluctuated largely with no discernible correlation to LH fluctuations. This may indicate that in these subjects the corpora lutea have some degree of autonomous regulation. W Wuttke, Abteilung für Klinische und Experimentelle Endokrinologie, Universitäts-Frauenklinik, Robert-Koch-Strasse 40, D-37075 Gottingen, Germany

LUTEAL MAINTENANCE IN THE HYPOPHYSECTOMIZED PSEUDOPREGNANT RABBIT: EFFECT OF OVINE LUTEINIZING HORMONE AND FOLLICLE-STIMULATING HORMONE

1972 ◽  
Vol 54 (1) ◽  
pp. 25-NP ◽  
Author(s):  
J. DAVIES ◽  
L. H. HOFFMAN ◽  
G. R. DAVENPORT
Keyword(s):  
Luteinizing Hormone ◽  
Follicle Stimulating Hormone ◽  
Normal Pregnancy ◽  
Detectable Effect ◽  
Corpora Lutea ◽  
Luteal Function ◽  
Daily Dose ◽  
Dose Levels ◽  
Limited Duration ◽  
Stimulating Hormone

SUMMARY Ovine luteinizing hormone (LH) (300 μg/day in divided subcutaneous doses) had a luteotrophic effect of limited duration in intact and hypophysectomized 10-day pseudopregnant rabbits (6–10 days in intact animals; 3–6 days in hypophysectomized animals). Higher dose levels caused reovulation in which case luteolysis occurred. Suppression of reovulation with anti-ovine follicle-stimulating hormone (FSH) serum permitted the daily dose of LH to be raised to 750 μg without causing luteolysis or reovulation. Anti-LH serum was luteolytic in the intact animals. A combination of ovine FSH (200 μg) and LH (300 μg) was indistinguishable from LH alone in terms of its luteotrophic effect in hypophysectomized 10-day pseudopregnant rabbits. Ovine FSH at large daily dose levels (1000 μg) was more effectively luteotrophic than LH alone in a significant number of animals for 10 days after hypophysectomy: endometrial changes in these animals resembled those only seen in normal pregnancy. The luteotrophic effect of 1000 μg FSH was believed to be dependent on a small but significant content of LH, estimated to be about 10 μg. Ovine FSH and anti-FSH serum in intact pseudopregnant rabbits had no detectable effect on luteal function. Animals hypophysectomized at the 7th day and treated with 300 or 500 μg LH/day showed no luteal maintenance for 6 days nor was reovulation induced. Sensitivity to the luteotrophic effect of LH was deemed, therefore, to be greater at 10 than at 7 days of pseudopregnancy. Endometrial criteria were found to be reliable indicators of luteal function. The appearance of ciliated cells was correlated with the decline of the corpora lutea. When reovulation occurred, a new progestational cycle was rapidly superimposed on the existing one.

scholarly journals Effects of Central Injection of Anti-LPS Antibody and Blockade of TLR4 on GnRH/LH Secretion during Immunological Stress in Anestrous Ewes

2014 ◽  
Vol 2014 ◽  
pp. 1-10 ◽  
Author(s):  
Karolina Haziak ◽  
Andrzej Przemysław Herman ◽  
Dorota Tomaszewska-Zaremba
Keyword(s):  
Luteinizing Hormone ◽  
Anterior Pituitary ◽  
Gonadotropin Releasing Hormone ◽  
Toll Like Receptor ◽  
Toll Like Receptor 4 ◽  
Immune Stress ◽  
Immunological Stress ◽  
Lh Release ◽  
Lh Secretion ◽  
Tlr4 Receptor

The present study was designed to examine the effect of intracerebroventricular (icv) administration of antilipopolysaccharide (LPS) antibody and blockade of Toll-like receptor 4 (TLR4) during immune stress induced by intravenous (iv) LPS injection on the gonadotropin-releasing hormone/luteinizing hormone (GnRH/LH) secretion in anestrous ewes. Injection of anti-LPS antibody and TLR4 blockade significantly (P < 0.01) reduced the LPS dependent lowering amount ofGnRHmRNA in the median eminence (ME). Moreover, blockade of TLR4 caused restoration ofLH-βtranscription in the anterior pituitary decreased by the immune stress. However, there was no effect of this treatment on reduced LH release. The results of our study showed that the blockade of TLR4 receptor in the hypothalamus is not sufficient to unblock the release of LH suppressed by the immune/inflammatory challenges. This suggests that during inflammation the LH secretion could be inhibited directly at the pituitary level by peripheral factors such as proinflammatory cytokines and circulating endotoxin as well.

Sign in / Sign up

Export Citation Format

Share Document