scholarly journals Vasopressinergic Activity of the Suprachiasmatic Nucleus and mRNA Expression of Clock Genes in the Hypothalamus-Pituitary-Gonadal Axis in Female Aging

2021 ◽  
Vol 12 ◽  
Author(s):  
Angela Cristina Nicola ◽  
Larissa Brazoloto Ferreira ◽  
Milene Mantovani Mata ◽  
Tatiane Vilhena-Franco ◽  
Cristiane Mota Leite ◽  
...  
Keyword(s):  
Mrna Expression ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Feedback Loops ◽  
Female Rats ◽  
Hpg Axis ◽  
Physiological Processes ◽  
Reproductive Axis ◽  
Reproductive Events ◽  
Vasopressinergic Neurons

The important involvement of the suprachiasmatic nucleus (SCN) and the activity of vasopressinergic neurons in maintaining the rhythmicity of the female reproductive system depends on the mRNA transcription-translation feedback loops. Therefore, circadian clock function, like most physiological processes, is involved in the events that determine reproductive aging. This study describes the change of mRNA expression of clock genes, Per2, Bmal1, and Rev-erbα, in the hypothalamus-pituitary-gonadal axis (HPG) of female rats with regular cycle (RC) and irregular cycle (IC), and the vasopressinergic neurons activity in the SCN and kisspeptin neurons in the arcuate nucleus (ARC) of these animals. Results for gonadotropins and the cFos/AVP-ir neurons in the SCN of IC were higher, but kisspeptin-ir was minor. Change in the temporal synchrony of the clock system in the HPG axis, during the period prior to the cessation of ovulatory cycles, was identified. The analysis of mRNA for Per2, Bmal1, and Rev-erbα in the reproductive axis of adult female rodents shows that the regularity of the estrous cycle is guaranteed by alternation in the amount of expression of Bmal1 and Per2, and Rev-erbα and Bmal1 between light and dark phases, which ceases to occur and contributes to determining reproductive senescence. These results showed that the desynchronization between the central and peripheral circadian clocks contributes to the irregularity of reproductive events. We suggest that the feedback loops of clock genes on the HPG axis modulate the spontaneous transition from regular to irregular cycle and to acyclicity in female rodents.

scholarly journals Minireview: Timely Ovulation: Circadian Regulation of the Female Hypothalamo-Pituitary-Gonadal Axis

Endocrinology ◽  
2006 ◽  
Vol 147 (3) ◽  
pp. 1148-1153 ◽  
Author(s):  
Horacio O. de la Iglesia ◽  
William J. Schwartz
Keyword(s):  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Female Rats ◽  
Circadian Regulation ◽  
Pituitary Cells ◽  
Neural Oscillators ◽  
Lh Surge ◽  
Pharmacological Data ◽  
Circadian Clock Genes ◽  
Estradiol Levels

The preovulatory surge in the secretion of LH is timed by a neuroendocrine integrative mechanism that involves ovarian estradiol levels and the endogenous circadian system. Studies in female rats and hamsters have established that the clock in the hypothalamic suprachiasmatic nucleus has a preeminent role in setting the LH surge, and anatomical, physiological, and pharmacological data are revealing the responsible connections between suprachiasmatic nucleus neurons and GnRH and estradiol-receptive areas. Recent investigations show that GnRH and pituitary cells express circadian clock genes that might play a role in the release and reception of the GnRH signal. Analysis of the circadian regulation of the LH surge may provide a model for understanding how multiple neural oscillators function within other neuroendocrine axes.

Knockdown of clock genes in the suprachiasmatic nucleus blocks prolactin surges and alters FRA expression in the locus coeruleus of female rats

2007 ◽  
Vol 293 (5) ◽  
pp. E1325-E1334 ◽  
Author(s):  
Maristela O. Poletini ◽  
De'Nise T. McKee ◽  
Jessica E. Kennett ◽  
Jamie Doster ◽  
Marc E. Freeman
Keyword(s):  
Circadian Rhythm ◽  
Locus Coeruleus ◽  
Suprachiasmatic Nucleus ◽  
Clock Genes ◽  
Random Sequence ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Gene Expressions ◽  
Circadian Time

The nature of the circadian signal from the suprachiasmatic nucleus (SCN) required for prolactin (PRL) surges is unknown. Because the SCN neuronal circadian rhythm is determined by a feedback loop of Period (Per) 1, Per2, and circadian locomotor output cycles kaput ( Clock) gene expressions, we investigated the effect of SCN rhythmicity on PRL surges by disrupting this loop. Because lesion of the locus coeruleus (LC) abolishes PRL surges and these neurons receive SCN projections, we investigated the role of SCN rhythmicity in the LC neuronal circadian rhythm as a possible component of the circadian mechanism regulating PRL surges. Cycling rats on proestrous day and estradiol-treated ovariectomized rats received injections of antisense or random-sequence deoxyoligonucleotide cocktails for clock genes ( Per1, Per2, and Clock) in the SCN, and blood samples were taken for PRL measurements. The percentage of tyrosine hydroxylase-positive neurons immunoreactive to Fos-related antigen (FRA) was determined in ovariectomized rats submitted to the cocktail injections and in a 12:12-h light:dark (LD) or constant dark (DD) environment. The antisense cocktail abolished both the proestrous and the estradiol-induced PRL surges observed in the afternoon and the increase of FRA expression in the LC neurons at Zeitgeber time 14 in LD and at circadian time 14 in DD. Because SCN afferents and efferents were probably preserved, the SCN rhythmicity is essential for the magnitude of daily PRL surges in female rats as well as for LC neuronal circadian rhythm. SCN neurons therefore determine PRL secretory surges, possibly by modulating LC circadian neuronal activity.

Effects of ageing and exogenous melatonin on pituitary responsiveness to GnRH in rats

Reproduction ◽  
2000 ◽  
pp. 151-156 ◽  
Author(s):  
E Diaz ◽  
D Pazo ◽  
AI Esquifino ◽  
B Diaz
Keyword(s):  
Body Weight ◽  
Reproductive System ◽  
Plasma Concentrations ◽  
Pituitary Hormones ◽  
Female Rats ◽  
Control Groups ◽  
Melatonin Treatment ◽  
Exogenous Melatonin ◽  
Reproductive Axis ◽  
Effect Of Age

The effect of age and melatonin on the activity of the neuroendocrine reproductive system was studied in young cyclic (3-5 months-old), and old acyclic (23-25 month-old) female rats. Pituitary responsiveness to a bolus of GnRH (50 ng per 100 g body weight) was assessed at both reproductive stages in control and melatonin-treated (150 micrograms melatonin per 100 g body weight each day for 1 month) groups. After this experiment, female rats were treated for another month to study the influence of ageing and melatonin on the reproductive axis. Plasma LH, FSH, prolactin, oestradiol and progesterone were measured. A positive LH response to GnRH was observed in both control groups (cyclic and acyclic). However, a response of greater magnitude was observed in old acyclic rats. Melatonin treatment reduced this increased response in acyclic rats and produced a pituitary responsiveness similar to that of young cyclic rats. FSH secretion was independent of GnRH administration in all groups, indicating desynchronization between LH and FSH secretion in response to GnRH in young animals and during senescence. No effect on prolactin was observed. Significantly higher LH (3009.11 +/- 1275.08 pg ml(-1); P < 0.05) and FSH concentrations (5879.28 +/- 1631.68 pg ml(-1); P < 0.01) were seen in acyclic control rats. After melatonin treatment, LH (811.11 +/- 89.71 pg ml(-1)) and FSH concentrations (2070 +/- 301.62 pg ml(-1)) decreased to amounts similar to those observed in young cyclic rats. However, plasma concentrations of oestradiol and progesterone were not reduced. In conclusion, the results of the present study indicate that, during ageing, the effect of melatonin is exerted primarily at the hypothalamo-pituitary axis rather than on the ovary. Melatonin restored the basal concentrations of pituitary hormones and pituitary responsiveness to similar values to those observed in young rats.

scholarly journals Alteration of circadian machinery in monocytes underlies chronic kidney disease-associated cardiac inflammation and fibrosis

2021 ◽  
Vol 12 (1) ◽  
Author(s):  
Yuya Yoshida ◽  
Naoya Matsunaga ◽  
Takaharu Nakao ◽  
Kengo Hamamura ◽  
Hideaki Kondo ◽  
...  
Keyword(s):  
Chronic Kidney Disease ◽  
Kidney Disease ◽  
Clock Genes ◽  
Serum Levels ◽  
Serum Retinol ◽  
Cardiac Inflammation ◽  
Physiological Processes ◽  
G Protein Coupled ◽  
Clock Protein

AbstractDysfunction of the circadian clock has been implicated in the pathogenesis of cardiovascular disease. The CLOCK protein is a core molecular component of the circadian oscillator, so that mice with a mutated Clock gene (Clk/Clk) exhibit abnormal rhythms in numerous physiological processes. However, here we report that chronic kidney disease (CKD)-induced cardiac inflammation and fibrosis are attenuated in Clk/Clk mice even though they have high blood pressure and increased serum angiotensin II levels. A search for the underlying cause of the attenuation of heart disorder in Clk/Clk mice with 5/6 nephrectomy (5/6Nx) led to identification of the monocytic expression of G protein-coupled receptor 68 (GPR68) as a risk factor of CKD-induced inflammation and fibrosis of heart. 5/6Nx induces the expression of GPR68 in circulating monocytes via altered CLOCK activation by increasing serum levels of retinol and its binding protein (RBP4). The high-GPR68-expressing monocytes have increased potential for producing inflammatory cytokines, and their cardiac infiltration under CKD conditions exacerbates inflammation and fibrosis of heart. Serum retinol and RBP4 levels in CKD patients are also sufficient to induce the expression of GPR68 in human monocytes. Our present study reveals an uncovered role of monocytic clock genes in CKD-induced heart failure.

scholarly journals The Increase in Signaling by Kisspeptin Neurons in the Preoptic Area and Associated Changes in Clock Gene Expression That Trigger the LH Surge in Female Rats Are Dependent on the Facilitatory Action of a Noradrenaline Input

Endocrinology ◽  
2016 ◽  
Vol 157 (1) ◽  
pp. 323-335 ◽  
Author(s):  
Bruna Kalil ◽  
Aline B. Ribeiro ◽  
Cristiane M. Leite ◽  
Ernane T. Uchôa ◽  
Ruither O. Carolino ◽  
...  
Keyword(s):  
Gene Expression ◽  
Median Eminence ◽  
Preoptic Area ◽  
Clock Genes ◽  
Third Ventricle ◽  
Female Rats ◽  
Ovariectomized Rats ◽  
Lh Surge ◽  
Clock Gene Expression

Abstract In rodents, kisspeptin neurons in the rostral periventricular area of the third ventricle (RP3V) of the preoptic area are considered to provide a major stimulatory input to the GnRH neuronal network that is responsible for triggering the preovulatory LH surge. Noradrenaline (NA) is one of the main modulators of GnRH release, and NA fibers are found in close apposition to kisspeptin neurons in the RP3V. Our objective was to interrogate the role of NA signaling in the kisspeptin control of GnRH secretion during the estradiol induced LH surge in ovariectomized rats, using prazosin, an α1-adrenergic receptor antagonist. In control rats, the estradiol-induced LH surge at 17 hours was associated with a significant increase in GnRH and kisspeptin content in the median eminence with the increase in kisspeptin preceding that of GnRH and LH. Prazosin, administered 5 and 3 hours prior to the predicted time of the LH surge truncated the LH surge and abolished the rise in GnRH and kisspeptin in the median eminence. In the preoptic area, prazosin blocked the increases in Kiss1 gene expression and kisspeptin content in association with a disruption in the expression of the clock genes, Per1 and Bmal1. Together these findings demonstrate for the first time that NA modulates kisspeptin synthesis in the RP3V through the activation of α1-adrenergic receptors prior to the initiation of the LH surge and indicate a potential role of α1-adrenergic signaling in the circadian-controlled pathway timing of the preovulatory LH surge.

scholarly journals Sex-specific vascular responses of the rat aorta: effects of moderate term (intermediate stage) streptozotocin-induced diabetes

2016 ◽  
Vol 94 (4) ◽  
pp. 408-415 ◽  
Author(s):  
Xiaoyuan Han ◽  
Sonali Shaligram ◽  
Rui Zhang ◽  
Leigh Anderson ◽  
Roshanak Rahimian
Keyword(s):  
Nitric Oxide ◽  
Nitric Oxide Synthase ◽  
Mrna Expression ◽  
Intermediate Stage ◽  
Diabetic Rats ◽  
Female Rats ◽  
Diabetic Rat ◽  
Male And Female ◽  
Male And Female Rats ◽  
Oxide Synthase

Hyperglycemia affects male and female vascular beds differently. We have previously shown that 1 week after the induction of diabetes with streptozotocin (STZ), male and female rats exhibit differences in aortic endothelial function. To examine this phenomenon further, aortic responses were studied in male and female rats 8 weeks after the induction of diabetes (intermediate stage). Endothelium-dependent vasodilation (EDV) to acetylcholine (ACh) was measured in phenylephrine (PE) pre-contracted rat aortic rings. Concentration response curves to PE were generated before and after L-NAME, a nitric oxide synthase (NOS) inhibitor. Furthermore, mRNA expression of endothelial nitric oxide synthase (eNOS) and NADPH oxidase subunit (Nox1) were determined. At 8 weeks, diabetes impaired EDV to a greater extent in female than male aortae. Furthermore, the responsiveness to PE was significantly enhanced only in female diabetic rats, and basal NO, as indicated by the potentiation of the response to PE after L-NAME, was reduced in female diabetic rat aortae to the same levels as in males. In addition, eNOS mRNA expression was decreased, while the Nox1 expression was significantly enhanced in diabetic female rats. These results suggest that aortic function in female diabetic rats after 8 weeks exhibits a more prominent impairment and that NO may be involved.

scholarly journals Seasonally sympatric but allochronic: differential expression of hypothalamic genes in a songbird during gonadal development

2018 ◽  
Vol 285 (1889) ◽  
pp. 20181735 ◽  
Author(s):  
Carolyn M. Bauer ◽  
Adam M. Fudickar ◽  
Skylar Anderson-Buckingham ◽  
Mikus Abolins-Abols ◽  
Jonathan W. Atwell ◽  
...  
Keyword(s):  
Gene Expression ◽  
Mrna Expression ◽  
Hormone Receptor ◽  
Gonadal Development ◽  
Luteinizing Hormone Receptor ◽  
Hpg Axis ◽  
Oestrogen Receptor Alpha ◽  
The Difference ◽  
Gonadal Recrudescence ◽  
Gonadotropin Inhibitory Hormone

Allochrony, the mismatch of reproductive schedules, is one mechanism that can mediate sympatric speciation and diversification. In songbirds, the transition into breeding condition and gonadal growth is regulated by the hypothalamic–pituitary–gonadal (HPG) axis at multiple levels. We investigated whether the difference in reproductive timing between two seasonally sympatric subspecies of dark-eyed juncos ( Junco hyemalis ) was related to gene expression along the HPG axis. During the sympatric pre-breeding stage, we measured hypothalamic and testicular mRNA expression of candidate genes via qPCR in captive male juncos. For hypothalamic mRNA, we found our earlier breeding subspecies had increased expression of gonadotropin-releasing hormone ( GnRH ) and decreased expression of androgen receptor, oestrogen receptor alpha and mineralocorticoid receptor ( MR ). Subspecies did not differ in expression of hypothalamic gonadotropin-inhibitory hormone ( GnIH ) and glucocorticoid receptor ( GR ). While our earlier breeding subspecies had higher mRNA expression of testicular GR , subspecies did not differ in testicular luteinizing hormone receptor, follicle-stimulating hormone receptor or MR mRNA expression levels. Our findings indicate increased GnRH production and decreased hypothalamic sensitivity to sex steroid negative feedback as factors promoting differences in the timing of gonadal recrudescence between recently diverged populations. Differential gene expression along the HPG axis may facilitate species diversification under seasonal sympatry.

Maintenance of Estrous Cycle in Female Rats with Anterior or Posterior Deafferentation of the Suprachiasmatic Nucleus

1988 ◽  
Vol 47 (5) ◽  
pp. 444-452 ◽  
Author(s):  
Kouji Nomura ◽  
Sumio Takahashi ◽  
Seiichiro Kawashima
Keyword(s):  
Estrous Cycle ◽  
Suprachiasmatic Nucleus ◽  
Female Rats

scholarly journals Effects of β‐hydroxy‐β‐methylbutyrate (HMB) on Muscle IGF‐I and MGF mRNA Expression in Aged Female Rats during 10‐Week Resistance Training

2010 ◽  
Vol 24 (S1) ◽  
Author(s):  
Young‐Min Park ◽  
Sang‐Rok Lee ◽  
Jacob M. Wilson ◽  
Paul C. Henning ◽  
Carlos Ugrinowitsch ◽  
...  
Keyword(s):  
Resistance Training ◽  
Mrna Expression ◽  
Female Rats ◽  
Igf I

scholarly journals Short-term regular moderate exercise improved male hypothalamic-pituitary-gonadal axis function via the reduction of hypothalamic neurokinin B expression in adult rats

2021 ◽  
Vol 25 (2) ◽  
pp. 171-177
Author(s):  
Nazli Khajehnasiri ◽  
◽  
Homayoun Khazali ◽  
Farzam Sheikhzadeh Hesari, ◽  
Hamid Reza Sadeghnia ◽  
...  
Keyword(s):  
Molecular Mechanisms ◽  
Serum Levels ◽  
Moderate Exercise ◽  
Short Term ◽  
Neurokinin B ◽  
Adult Rats ◽  
Hpg Axis ◽  
Intensive Exercise ◽  
Reproductive Axis ◽  
Gnrh Neurons

Introduction: In the arcuate nucleus, kisspeptin, neurokinin-B and pro-dynorphin (KNDy) neurons control the function of gonadotropin-releasing hormone (GnRH) neurons. Early investigations indicated that exercise with various intensities affects luteinizing hormone (LH) and testosterone (T) in different ways. Meanwhile the molecular mechanisms underlying its function not yet been fully understood. Accordingly, the present study evaluated the role of alterations in the levels of KNDy mRNA upstream of GnRH neurons in conveying the effects of various short-term exercise intensities on the male hypothermic-pituitary-gonadal (HPG) axis. Methods: Twenty-one adult Wistar rats were randomly divided into 3 groups: control, one-month regular moderate exercise (ME) and one-month regular intensive exercise (IE). In ME (22m/min) and IE (35m/min) groups, the rats were treated 5 days a week for 60min each day. Finally, we assessed serum levels of LH and T using the ELIZA technique and KNDy and Gnrh mRNA expression by the real-time PCR method. Results: The results revealed that in ME group the expression of Nkb was reduced and the expression of Gnrh mRNA and the LH and T serum levels were increased. However, intensive exercise did not change the serum levels of LH and T or the relative expression of kiss1, Nkb, Pdyn and Gnrh genes. Conclusion: The results suggested that monthly moderate exercise improved male reproductive axis function, while intensive exercise did not have an adverse effect on the reproductive axis. These various effects on the male HPG axis may be propagated by the change in hypothalamic Nkb gene expression.

Sign in / Sign up

Export Citation Format

Share Document