• Animal cells and systems
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• v.3 no.1
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• pp.1-7
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• 1999

Gonadotropin-releasing hormone (GnRH) was originally isolated as a hypothalamic peptide that regulates reproduction by stimulating the release of gonadotropins. Using comparative animal models has led to the discovery that GnRH has a more ancient evolutionary origin. Durinq evolution GnRH peptide underwent gene duplication and structural changes to give rise to multiple molecular forms of GnRHs. Mammalian GnRH initially considered to be the sole molecular form, is now grouped as a family of peptides along with GnRH variants determined from representatives in all classes of vertebrates. Vertebrate species including primates and humanshave more than one GnRH variant in individual brains; a unique GnRH form in the forebrain and chicken IIGnRH in the midbrain. Furthermore, several species of bony fish have three molecular variants of GnRH: salmon GnRH sea-bream GnRH and chicken II GnRH. Also, it has been shown that in addition to the olfactory placodes and the midbrain, there is a third embryonic source of GnRH neurons from the basal diencephalon in birds and fish, which might be true for other vertebrates. Therefore, comparative animal models like fish with discrete sites of expression of three molecular variants of GnRH in individual brains, could provide insight into novel functions of GnRH variants, conservation of gene regulation, and mechanisms governing reproduction in vertebrates.

• Biomedical Science Letters
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• v.15 no.3
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• pp.249-255
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• 2009

All living things have been developed efficient strategies to cope with external and internal environmental changes via a process termed 'homeostasis'. However, chronic prenatal maternal stress may significantly contributes to pregnancy complications by disturbing hypothalamic-pituitary-adrenal (HPA) axis and the automatic nervous system (ANS), and results in unfavorable development of the fetus. Dysregulation of these two major stress response systems lead to the increased secretion of the glucocorticoids (GCs) which are known to be essential for normal development and the maturation of the central nervous system. As Hox genes are master key regulators of the embryonic morphogenesis and cell differentiation, we aimed to determine the effects of dexamethasone, a potent synthetic glucocorticoid, on gene expression in mesenchymal stem cell C3H10T1/2. Analysis of 39 Hox genes based on reverse transcription PCR (RT-PCR) method revealed that the expression patterns of Hox genes were overall upregulated by long dexametasone treatment. These results indicate that maternal stress may have a deleterious effect on early developing embryo through the stress hormone, glucocorticoid.

• Clinical and Experimental Pediatrics
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• v.57 no.10
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• pp.425-433
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• 2014

Adrenal and thyroid hormones are essential for the regulation of intrauterine homeostasis, and for the timely differentiation and maturation of fetal organs. These hormones play complex roles during fetal life, and are believed to underlie the cellular communication that coordinates maternal-fetal interactions. They serve to modulate the functional adaptation for extrauterine life during the perinatal period. The pathophysiology of systemic vasopressor-resistant hypotension is associated with low levels of circulating cortisol, a result of immaturity of hypothalamic-pituitary-adrenal axis in preterm infants under stress. Over the past few decades, studies in preterm infants have shown abnormal clinical findings that suggest adrenal or thyroid dysfunction, yet the criteria used to diagnose adrenal insufficiency in preterm infants continue to be arbitrary. In addition, although hypothyroidism is frequently observed in extremely low gestational age infants, the benefits of thyroid hormone replacement therapy remain controversial. Screening methods for congenital hypothyroidism or congenital adrenal hyperplasia in the preterm neonate are inconclusive. Thus, further understanding of fetal and perinatal adrenal and thyroid function will provide an insight into the management of adrenal and thyroid function in the preterm infant.

• Journal of Acupuncture Research
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• v.15 no.2
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• pp.29-41
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• 1998

The effect of Cervi Cornu Parvum aqua-acupuncture on serum levels of sex hormone was investigated in ovariectomized rats. Water extract of Cervi Cornu Parvum was daily injected for 30 days at points in rats corresponding to bilateral Taixi (Ki. 3) points of human and non-point at root of tail after ovariectomy, respectively. Serum levels of estradiol, testosterone, progesterone, LH and FSH were measured at 2 and 4 weeks after aqua-acupuncture treatment, respectively. Compared with ovariectomized rats, significant increase of estradiol and progesterone and significant decrease of FSH and LH were elicited at 2 and 4 weeks after aqua-acupuncture treatment. Aqua-acupuncture treatment at non-point did not produce any remarkable effect. These findings suggest aqua-acupuncture may restore dysfunction of hypothalamic-pituitary-ovarian axis, associated with a significant increase of serum estradiol level in ovariectomized rats.

• Proceedings of the Zoological Society Korea Conference
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• 1996.10a
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• pp.151.2-151
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• 1996

No Abstract, See Full Text

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.17
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• pp.7701-7705
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• 2015

Background: Thyroid hormones (TH) are regulated by the hypothalamic-pituitary axis, which plays an important role in cell growth, differentiation, development and other aspects of metabolism. It is believed that an active hypothalamic-pituitary axis increases the susceptibility of thyroid dysfunction during systemic chemotherapy. In order to investigate the relation between thyroid function and chemotherapy the present study was designed to investigate TH in breast cancer patients receiving at least three cycles of chemotherapy. The levels of TH were measured at the baseline and before each cycle of chemotherapy. Materials and Methods: Blood samples for estimation of TH levels were collected from 80 (pre-menopausal-40; post-menopausal-40) breast cancer patients just before they were undergoing - $1^{st}$, $2^{nd}$, $3^{rd}$ and $4^{th}$ cycle of chemotherapy. The serum was separated and $T_3$, $T_4$ and TSH levels were determined by chemiluminescence method. Results: $T_3$ and $T_4$ were found significantly decreased and TSH was found significantly increased after $1^{st}$ (p<0.001), $2^{nd}$ (p<0.0001) and $3^{rd}$ cycle of chemotherapy (p<0.0001). The variation of $T_3$ levels (decreased) and TSH levels (increased) was found more in post-menopausal (p<0.0001) women then in pre-menopausal women after $3^{rd}$ cycle of chemotherapy as compared to baseline (p<0.001). Conclusions: TH were remarkably altered after each cycle of chemotherapy leading to decline in thyroid function of breast cancer patients. Further, the results also indicated that post-menopausal women were more prone towards decline in thyroid function then pre-menopausal women. The present study proposes the monitoring of TH after each cycle of chemotherapy in breast cancer patients.

• The Korean Journal of Zoology
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• v.39 no.4
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• pp.337-351
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• 1996

Melatonin Is a multifunctional hormone secreted from the pineal gland in the middle of cerebrum and cerebellum. Its synthesis and release reflect photopedod;Photopedod is a yearly predictable ambient factor that most animals utilize as an environmental cue for maximum survival. Hamsters maintaln reproductive activity in summer during which day length exceeds night time. Upon the advent of autumnal equinox they undergo gonadal regression. The photoperiodic effects are prevented by removal of the pineal gland and restored by the timed repiacument of melatonin. The results suggest that melatonin constitutes part of control mechanism whereby environmental information is transduced to neuroendocrine signal responsIble for the functional integrity of the reproductive system. From the studies for the action site of melatonin following the treatment of photopedod or melatonin in the lesion of a spedflc portion of hypothalamus, suprachiasmatic nuclei and pars tuberalis are shown to be a consensus site for melatonIn. The action of melatonin. In the regulation of reproduction is largely unknown. It is mainly due to the lack of acute effect of melatonin on gonadotropin secretion. However, reduction of the gonadotropln release and augmentation of the hypothalamic gonadotropin-releasing hormone (GnRH) content by long-term treatment of melatonln Indicate that constant presence of melatonln may partidpate in the regulation of sexual activity via the GnRH neuronal system. The action mechanism by which melatonin exerts Its effect on GnRH neuron needs to be eluddated. The inability of opiold analogues to affect the reproductive hormones in sexually regressed animals by inhibftory photopedod and melatonin suggests that the opioldergic neuron may be a prime intervening mediator. Recent cloning of melatonin receptor will contribute to investigate its anatomical Identification and the action mechanism of melatonin on target tissues at the molecular level.

• Animal Bioscience
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• v.35 no.12
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• pp.1850-1859
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• 2022

Objective: The quantitative reverse transcription polymerase chain reaction (qPCR) is the most accurate and reliable technique for analysis of gene expression. Endogenous reference genes (RGs) have been used to normalize qPCR data, although their expression may vary in different tissues and experimental conditions. Verification of the stability of RGs in selected samples is a prerequisite for reliable results. Therefore, we attempted to identify the most stable RGs in the hypothalamic-pituitary-gonadal (HPG) axis in sows. Methods: The cycle threshold values of nine commonly used RGs (18S, HPRT1, GAPDH, RPL4, PPIA, B2M, YWHAZ, ACTB, and SDHA) from HPG axis-related tissues in the domestic sows in the different stages of estrus cycle were analyzed using two RG-finding programs, geNorm and Normfinder, to rank the stability of the pool of RGs. In addition, the effect of the most and least stable RGs was examined by normalization of the target gene, gonadotropin-releasing hormone (GnRH), in the hypothalamus. Results: PPIA, HPRT1, and YWHAZ were the most stable RGs in the HPG axis-related tissues in sows regardless of the stages of estrus cycle. In contrast, traditional RGs, including 18S and ACTB, were found to be the least stable under these experimental conditions. In particular, in the normalization of GnRH expression in the hypothalamus against several stable RGs, PPIA, HPRT1, and YWHAZ, could generate significant (p<0.05) elevation of GnRH in the preovulatory phase compared to the luteal phase, but the traditional RGs with the least stability (18S and ACTB) did not show a significant difference between groups. Conclusion: These results indicate the importance of verifying RG stability prior to commencing research and may contribute to experimental design in the field of animal reproductive physiology as reference data.

• Journal of Ginseng Research
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• v.32 no.1
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• pp.8-14
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• 2008

Stress activates hypothalamic-pituitary-adrenal (HPA) axis and subsequently increases the systemic levels of glucocorticoids. It also inhibits the release of gonadotropin-releasing hormone (GnRH) from hypothalamus. Korean ginseng (Panax ginseng CA Meyer) has been proven as an anti-stress agent. However, most of the anti-stress effects of ginseng on stresses such as immobilization, electronic foot shock, and cold swim, which subsequently cause oxidative damage in brain, were obtained by using ginseng extract or ginseng total saponin. Moreover, anti-stress and anti-oxidative effects of ginseng were demonstrated by determination of enzyme or hormone levels but not mRNA as well as transcriptome. Further studies on transcriptome, proteomics, and systems biology as well as signal transduction would be required to elucidate molecular action mechanisms of ginseng on stresses.

• Development and Reproduction
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• v.1 no.2
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• pp.189-202
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• 1997

The hypothalamic peptide GnRH plays a central role in the regulation of the mammalian reproductive axis. Recent studies suggested that GnRH stimulates or inhibits the ovarian steroidogenesis and gametogenesis directly. Our previous report indicated that GnRH gene is expressed in adult rat ovary as well as in hypothalamus and that the expressed GnRH may induce the follicular atresia and apoptosis of ovarian granulosa cells in rat. Therfore, we studied whether GnRH gene is expressed in the mouse fetal ovary, when the germ cells are degenerating by apoptosis during gonad diffeerentiation. Mouse fetal gonads were obtained on the 12, 15,18 and 20th day of gestation from the mother mice superovulated (10 IU PMSG and 10 IU hCG) and mated. The morphological changes of fetal ovaries were examined histochemically by hematoxylin-eosin staining. The fetal sex was confirmed by PCR methods for sexing. RT-PCR methods were used to examine the expression of GnRH gene and the sex steroid hormones were determined by conventional radioimmunoassays. The levels of estradiol (E) and progesterone (P) were increaseduntil 18th day of gestation and then E was decreased just before parturition. The morphological changes of fetal gonadal tissue sections showed the ovarian development and coincided with the result of PCR analysis for sexing using ovary- or testis- specific oligonucleotide primers. Immunoreactive GnRH in placenta was decreased gradually until the end of gestation but fetal brain and ovarian GnRH were increased. The level of GnRH gene expression was increased during fetal ovarian development from 12 till 18th day and decreased suddenly on 20th day just before birth. From these results, it is suggested that ovarian GnRh may play a regulatory role on the germ cell differentiation of fetal ovary.