Displaying publications 1 - 20 of 30 in total

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  1. Azmi TI, Bongso TA, Harisah M, Basrur PK
    Can. J. Vet. Res., 1990 Jan;54(1):93-8.
    PMID: 2306676
    The ultrastructure of Sertoli cells in the seminiferous tubules of water buffaloes before and during sexual maturity was studied by transmission electron microscopy, with emphasis on the intranucleolar vesicular elements. Sertoli cells of animals under 12 months of age were distinguished from the germ cells by the presence of electron dense membrane bound bodies within their cytoplasm. These cells, referred to as basal indifferent supporting cells, were probably involved in the phagocytosis and elimination of degenerating spermatocytes, which failed to differentiate into spermatids and spermatozoa in animals under one year of age. In 12 month old animals, a few Sertoli cells exhibiting the vesicular elements appeared in the nucleolar region while in animals over 15 months of age Sertoli cells could be positively identified by the characteristic cytoplasm containing microtubules, elongated and electron dense mitochondria, extensive granular endoplasmic reticulum and the presence of spermatids in various stages of spermiogenesis. The vesicular elements in the nucleolar region of the Sertoli cells were most prominent at this stage. Ultrastructural features of the Sertoli cells revealed an abundance of ribosome-like particles surrounding the vesicles of varying size. Some of these vesicular elements contained amorphous material suggesting that they represent the products sequestered in the nuclear region for transport to the cytoplasm and that the process of spermiogenesis may be dependent on the ability of Sertoli cells to generate these products at sexual maturity.
    Matched MeSH terms: Sexual Maturation/physiology
  2. Chong LS, Chin YS, Gan WY, Nasir MT
    Asia Pac J Clin Nutr, 2017 Mar;26(2):326-333.
    PMID: 28244713 DOI: 10.6133/apjcn.012016.10
    BACKGROUND AND OBJECTIVES: To determine the associations between socio-demographic characteristics and pubertal status with disordered eating among primary school children.

    METHODS AND STUDY DESIGN: Using a stratified multi-stage sampling, a total of 816 children (282 boys and 534 girls) aged 10 to 11 years from 12 selected primary schools in the state of Selangor, participated in this study. Data were collected on socio-demographic characteristics, pubertal status and disordered eating behaviors. The Pubertal Development Scale and the Children's Eating Attitudes Test (ChEAT) were used to assess pubertal status and disordered eating, respectively. Logistic regression analysis was conducted to determine the risk factors of disordered eating.

    RESULTS: The prevalence of disordered eating was 30.8% (32.8% in boys and 29.7% in girls). However, the sex difference in the prevalence was not statistically significant. Age, ethnicity and pubertal status were significantly associated with disordered eating in univariate logistic regression analysis. Multivariate logistic regression analysis showed that among boys, being either in an advanced or post-pubertal stage (adjusted OR=8.64) and older age group (adjusted OR=2.03) were risk factors of disordered eating. However, among girls, being a Malay (adjusted OR=3.79) or Indian (adjusted OR=5.04) in an advanced or post-pubertal stage (adjusted OR=2.34) and older age group (adjusted OR=1.53) were risk factors of disordered eating.

    CONCLUSION: This study found one in three children had disordered eating. Since ethnicity and pubertal status were identified as risk factors, ethnicity-specific intervention programs on the prevention of disordered eating among children should take into consideration their pubertal status.

    Matched MeSH terms: Sexual Maturation
  3. Faiz ZM, Mardhiyyah MP, Mohamad A, Hidir A, Nurul-Hidayah A, Wong L, et al.
    Anim. Reprod. Sci., 2019 Oct;209:106143.
    PMID: 31514941 DOI: 10.1016/j.anireprosci.2019.106143
    Understanding Macrobrachium rosenbergii ovarian maturation control at the genome level is an important aspect for increasing larvae production. In this study, an ovarian maturation related gene, M. rosenbergii vWD domain and three Kazal-type domains of a gene (MrvWD-Kazal) have been studied. The MrvWD-Kazal gene was isolated using a rapid amplification of cDNA end (RACE) method and the relative abundances of MrvWD-Kazal mRNA in the ovary, hepatopancreas, stomach, intestine and gill were determined by using the quantitative PCR technique. The MrvWD-Kazal gene is composed of 2194 bp with an open reading frame (ORF) of 1998 bp encoding 665 amino acids and has great similarity to the M. nipponense vWD-Kazal gene (91%). The qPCR analyses indicated the relative abundance of MrvWD-Kazal mRNA transcript varied among different stages of ovarian function (P < 0.05), but there were no differences abundance in hepatopancreas, stomach, intestine and gill (P> 0.05). In the ovary, relative abundance of MrvWD-Kazal mRNA transcript gradually increased with ovarian maturation from Stages 1 (Spent; 1.00-fold), to 2 (Proliferative; 3.47-fold) to 3 (Premature; 6.18-fold) and decreased at Stage 4 (Mature; 1.31-fold). Differential relative abundances of MrvWD-Kazal mRNA transcript in the ovary indicate the MrvWD-Kazal protein may have an important function in ovarian maturation of M. rosenbergii. The results of this study also indicate the MrvWD-Kazal is not involved in regulation of the reproductive related function of the hepatopancreas, digestive system (stomach and intestine) and respiratory system (gill).
    Matched MeSH terms: Sexual Maturation/genetics
  4. Fayez A Almabhouh, Faizatul Isyraqiah Ahmad Muhammad, Hisham Ibrahim, Harbindarjeet Singh
    MyJurnal
    Leptin, a 16 kDa protein and a product of the ob/ob gene, has a tertiary structure similar to that
    of a cytokine. It is primarily secreted by white adipose tissue and its levels in the blood correlate
    positively with percentage body fat. Leptin was first identified in 1994 as a major factor that
    regulated food intake and energy balance. Leptin in the circulation exists either as a free
    monomeric hormone or bound to its soluble receptor. Its serum levels usually range from 0.5 to
    37.7 ng/ml in males and 2.0 to 45.2 ng/ml in females. The half-life of leptin is between 20 - 30
    minutes and it is eliminated mainly by the kidneys. However, research over the last 25 years
    has revealed numerous other physiological roles for leptin, including roles in inflammation,
    immune function, neuro-endocrine function, bone metabolism, blood pressure regulation and
    sexual maturation. Most of these roles have been identified from studies on leptin deficient
    rodents. Apart from energy balance and sexual maturation, where its role is direct and obvious,
    its actions on the rest of the other systems are permissive. Actions of leptin are both centrally
    and peripherally mediated involving receptors that are widely distributed in the body. Six leptin
    receptor isoforms, belonging to the class 1 cytokine receptor family, have been identified.
    These receptors are products of the OBR gene. The cellular actions of leptin are mediated
    through any one of five different signalling pathways that include the JAK-STAT, PI3K, MAPK,
    AMPK, and the mTOR signalling pathways.
    Matched MeSH terms: Sexual Maturation
  5. Jahanfar S, Lye MS, Krishnarajah IS
    Indian J Hum Genet, 2013 Apr;19(2):245-50.
    PMID: 24019629 DOI: 10.4103/0971-6866.116127
    INTRODUCTION: Menarche or first menstrual period is a landmark in reproductive life span and it is the most prominent change of puberty. The timing of menarche can be under the influence of genes as well as individual environmental factors interacting with genetic factors.

    OBJECTIVE: Our study objectives were (a) to investigate the heritability of age of menarche in twins, (b) to obtain the association between age of menarche and childhood factors, and reproductive events/behavior, (c) to examine whether or not having a male co-twin affects early/late menarche.

    METHODOLOGY: A group of female-female identical (n = 108, 54 pairs), non-identical twins (n = 68, 34 pairs) and 17 females from opposite-sex twin sets were identified from twin registries of Malaysia and Iran. Genetic analysis was performed via two methods of Falconers' formula and maximum likelihood.

    RESULTS: Heritability was found to be 66% using Falconers' formula and 15% using univariate twin analysis. Model analysis revealed that shared environmental factors have a major contribution in determining the age of menarche (82%) followed by non-shared environment (18%).

    DISCUSSION: Result of this study is consistent with that of the literature. Timing of menarche could be under the influence of shared and non-shared environmental effects. Hirsutism was found to have a higher frequency among subjects with late menarche. There was no significant difference in age of menarche between females of opposite-sex twins and females of same-sex twins.

    CONCLUSION: It is concluded that twin models provide a powerful means of examining the total genetic contribution to age of menarche. Longitudinal studies of twins may clarify the type of environmental effects that determine the age of menarche.

    Matched MeSH terms: Sexual Maturation
  6. Jayachandra S, D'Souza UJ
    J Environ Sci Health B, 2014;49(4):271-8.
    PMID: 24502214 DOI: 10.1080/03601234.2014.868287
    The objective of this research is to study the possible reproductive adverse effects of diazinon on rat offspring exposed in utero and during lactation. Twenty-four Sprague-Dawley female rats (10-12 week old) were randomly assigned to four groups, each consisting of six rats. Group 1 served as the control and these rats were given normal saline orally. Rats in groups 2, 3, and 4 were administered diazinon, dissolved in saline at 10, 15, 30 mg/ kg(-1) body weight, per oral, once daily, during mating, pregnancy and lactation. The male offsprings were examined at puberty and adulthood for body weight, testis weight, epididymis weight, sperm count, motility and morphology, pituitary-gonadal hormone levels. At 30 mg kg(-1) dose, the male offsprings showed a decrease in testicular weight, sperm count, motility, with an increase in abnormal sperm percentage and a decline in pituitary-gonadal hormones, at puberty. Upon attaining adulthood, there was a decrease in testicular weight, sperm count and motility with an increase in abnormal sperm percentage and a decrease in pituitary hormone level. There was evidence of some adverse reproductive effects on the male offspring at the 15 mg/ kg(-1) dose. Most of the adverse effects were irreversible and were evident at both puberty and adulthood in the offsprings, although a few parameters reverted to the normal growth pattern. Diazinon is a reproductive toxicant for male offsprings if exposed during prenatal and postnatal phases.
    Matched MeSH terms: Sexual Maturation/drug effects
  7. Kamrani, M.A., Sharifah Zainiyah, S.Y., Hamzah, A., Ahmad, Z.
    MyJurnal
    Adolescents are known to obtain information regarding sexual and reproductive health from a variety of sources and not just during formal lessons in schools. This cross-sectional descriptive study was carried out to determine the source of information on sexual and reproductive health among Form four secondary schools girls in the Klang Valley as well as parents’ relationship profile. A total of 520 secondary school girls were recruited for the study. In this study, the source of information on puberty and sexual topics were categorized as follows: first level of importance - mothers, second level of importance - siblings, third level of importance - fathers, fourth level of importance - friends, fifth level of importance - teachers and sixth level of importance - books/internet. A majority of respondents agreed that their mothers were the first level of importance they sought for information on puberty (74.8%) and sexual topics (53.8%). Thirty nine point three percent (39.3%) of respondents reported it was very easy to have a dialogue with their mothers while only 10.0% of the respondents said it was very easy to have a dialogue with their fathers. While this was the case, only 6.3% of the respondents reported discussing sex-related matter with their mothers.
    Matched MeSH terms: Sexual Maturation
  8. Kitahashi T, Ogawa S, Soga T, Sakuma Y, Parhar I
    Endocrinology, 2007 Dec;148(12):5822-30.
    PMID: 17823257
    The role of steroid/thyroid hormones in the regulation of endocrine cells at the level of the pituitary has remained unclear. Therefore, using single-cell quantitative real-time PCR, we examined absolute amounts of transcripts for nuclear receptors [estrogen receptors (ERs) alpha, beta, and gamma; androgen receptors (ARs) a and b; glucocorticoid receptors (GRs) 1, 2a, and 2b; and thyroid hormone receptors (TRs) alpha1, alpha2, and beta] in pituitary cells of immature (IM) and mature (M) male tilapia, Oreochromis niloticus. In the two reproductive stages, ACTH cells expressed only ERbeta, whereas all other pituitary cell types expressed ERalpha + beta, and a subpopulation coexpressed ARa, ARb, GR1, GR2b, and TRbeta but lacked ERgamma, GR2a, TRalpha1, and TRalpha2. IM males had high percentages of LH cells (IM 46.0% vs. M 10.0%), GH cells (IM 23.3% vs. M 7.9%), and prolactin cells (IM 68.8% vs. M 6.0%) with ERbeta, and TSH cells (IM 19.2% vs. M 0.0%) and MSH cells (IM 25.6% vs. M 0.0%) with ERalpha + TRbeta. A high percentage of FSH cells in IM males expressed ERbeta (IM 46.9% vs. M 18.8%), and FSH cells in M males showed significantly high GR1 transcripts (IM 76.0 +/- 5.0 vs. M 195.0 +/- 10.7 copies per cell; P < 0.05), suggesting that FSH cells are regulated differently in the two reproductive stages. Coexpression of ERalpha + beta in high percentages of cells of the GH family (GH, IM 43.8% vs. M 14.3%; prolactin, IM 8.3% vs. M 59.7%; somatolactin, IM 22.2% vs. M 42.2%) suggests that the expression of both ERs is important for functionality. Thus, differential coexpression of genes for nuclear receptors in subpopulations of pituitary cell types suggests multiple steroid/thyroid hormone regulatory pathways at the level of the pituitary during the two reproductive stages.
    Matched MeSH terms: Sexual Maturation
  9. Lee, Yee Lin, Salwati Shuib, Wu, Loo Ling
    MyJurnal
    In contrast to classic Turner syndrome, Turner patients with ring X chromosome are associated with distinct dysmorphism and are likely to be mentally impaired. Four Turner patients with ring X chromosome were examined for phenotypic features of Turner syndrome and additional dysmorphism. Both patients 1 and 2 are twins with normal intelligence whereas patients 3 and 4 have mental impairment. With the exception of patient 4, the other three patients only have few Turner characteristics. None of the patients have the distinctive dysmorphism previously reported in Turner syndrome with ring X chromosome. Both twins developed spontaneous puberty. Patients 3 and 4 however had no spontaneous puberty. We postulate that this variation may be related to the ring size, the proportion of 45,X and ring X chromosome in cell lines of various body tissues as well as the ability of these rings to be inactivated as a result of lyonisation.
    Matched MeSH terms: Sexual Maturation
  10. Li G, Tang H, Chen Y, Yin Y, Ogawa S, Liu M, et al.
    Mol Cell Endocrinol, 2018 02 05;461:1-11.
    PMID: 28801227 DOI: 10.1016/j.mce.2017.08.003
    The LHb expression is up-regulated during puberty in female zebrafish. However, the molecular mechanism underlying how LHb expression is regulated during puberty remains largely unknown. In this study, we found that the mRNA expression levels of lhb, fshb and cyp19a1b were up-regulated along with the puberty onset in zebrafish. Among the three nuclear estrogen receptors (nERs), the esr2b is the only type whose expression is significantly up-regulated during puberty onset in the pituitary. However, in situ hybridization results revealed that lhb mRNA was colocalized with esr1 and esr2a but not esr2b. Exposure to estradiol (E2) significantly stimulates LHb expression in both wild-type and kiss1-/-;kiss2-/-;gnrh3-/- triple knockout pubertal zebrafish. Moreover, exposure of cultured pituitary cells to E2 increased the LHb expression, indicating that the estrogenic effect on LHb expression could be acted at the pituitary level. Finally, we cloned and analyzed the promoter of lhb by luciferase assay. Our results indicated that the E2 responsive regions of lhb promoter for ERα and ERβ2 are identical, suggesting that ERα and ERβ2 could bind to the same half ERE region of the promoter of lhb, exhibiting a classical ERE-dependent pathway. In summary, we demonstrate that E2 could directly act on the pituitary level to stimulate LHb transcription during puberty in zebrafish.
    Matched MeSH terms: Sexual Maturation/drug effects*
  11. Loganathan K, Moriya S, Sivalingam M, Ng KW, Parhar IS
    J. Chem. Neuroanat., 2017 Dec;86:92-99.
    PMID: 29074372 DOI: 10.1016/j.jchemneu.2017.10.004
    kcnk10a has been predicted in zebrafish to be a member of the two-pore domain potassium ion (K+) channel-related K+ (TREK) channel family known as a thermoreceptor. Since reproduction is affected by temperature, Kcnk10a could be involved in the regulation of reproduction. However, expression of kcnk10a in the zebrafish brain and association with reproduction has not been identified. In this study, the full length sequence and localization of kcnk10a in the brain was investigated and gene expressions of the TREK channel family were examined to investigate association with reproduction. We initially identified the full length cDNA sequence of kcnk10a using Rapid Amplification of cDNA Ends and localization in the zebrafish brain using in situ hybridization. Furthermore, we examined the gene expression differences of kcnk2b, kcnk10a and kcnk10b mRNA between genders as well as developmental stages by real-time PCR. The deduced amino acid sequence of the identified kcnk10a mRNA contains highly conserved two pore domains and four transmembrane regions and was higher similarity to zebrafish Kcnk10b than zebrafish Kcnk2a and 2b. kcnk10a mRNA was widely distributed in the brain such as the preoptic area, hypothalamus and the midbrain. kcnk10a mRNA expression exhibited significant difference between mature male and female, and increase during puberty. Kcnk10a could be involved in the regulation of reproductive function.
    Matched MeSH terms: Sexual Maturation
  12. M Selveindran N, Syed Zakaria SZ, Jalaludin MY, Rasat R
    Horm Res Paediatr, 2017;88(5):324-330.
    PMID: 28965114 DOI: 10.1159/000478780
    BACKGROUND/AIMS: Disorders of sex development (DSD) are a heterogeneous group of rare conditions. Evidence-based treatment is challenged by a lack of clinical longitudinal outcome studies. We sought to investigate the quality of life of children with DSD other than congenital adrenal hyperplasia.

    METHODS: The participants (aged 6-18 years) were 23 patients raised as males and 7 patients raised as females. Control data were obtained from representatives of the patients' siblings matched for age and gender. The Pediatric Quality of Life InventoryTM Version 4.0 (PedsQL) Generic Core Scales were used as the study tool.

    RESULTS: In comparison with the reference data, the patient group had significantly lower overall PedsQL (p < 0.01) and school functioning (p < 0.01) scores. Also, the total PedsQL score was significantly lower in patients with DSD who were of female social sex as compared to the controls who were females. Family income, surgical procedures, degree of virilization, and mode of puberty did not influence the PedsQL scores.

    CONCLUSION: This study revealed a poorer quality of life for patients with DSD as compared to the age-matched control group. This highlights the need for a skilled multidisciplinary team to manage this group of patients.

    Matched MeSH terms: Sexual Maturation
  13. Muchlisin ZA, Musman M, Azizah MN
    PMID: 20482777 DOI: 10.1186/1477-7827-8-49
    Rasbora tawarensis is an endemic freshwater fish in Lake Laut Tawar, Aceh Province, Indonesia. Unfortunately, its status is regarded as critical endangered with populations decreasing in recent years. To date no information on the spawning activities of the fish are available. Therefore, this study provides a contribution to the knowledge on reproductive biology of R. tawarensis especially on spawning seasons as well as basic information for conservation of the species.
    Matched MeSH terms: Sexual Maturation/physiology
  14. Putteeraj M, Soga T, Ubuka T, Parhar IS
    PMID: 27630616 DOI: 10.3389/fendo.2016.00121
    Reproduction is associated with the circadian system, primarily as a result of the connectivity between the biological clock in the suprachiasmatic nucleus (SCN) and reproduction-regulating brain regions, such as preoptic area (POA), anteroventral periventricular nucleus (AVPV), and arcuate nucleus (ARC). Networking of the central pacemaker to these hypothalamic brain regions is partly represented by close fiber appositions to specialized neurons, such as kisspeptin and gonadotropin-releasing hormone (GnRH) neurons; accounting for rhythmic release of gonadotropins and sex steroids. Numerous studies have attempted to dissect the neurochemical properties of GnRH neurons, which possess intrinsic oscillatory features through the presence of clock genes to regulate the pulsatile and circadian secretion. However, less attention has been given to kisspeptin, the upstream regulator of GnRH and a potent mediator of reproductive functions including puberty. Kisspeptin exerts its stimulatory effects on GnRH secretion via its cognate Kiss-1R receptor that is co-expressed on GnRH neurons. Emerging studies have found that kisspeptin neurons oscillate on a circadian basis and that these neurons also express clock genes that are thought to regulate its rhythmic activities. Based on the fiber networks between the SCN and reproductive nuclei such as the POA, AVPV, and ARC, it is suggested that interactions among the central biological clock and reproductive neurons ensure optimal reproductive functionality. Within this neuronal circuitry, kisspeptin neuronal system is likely to "time" reproduction in a long term during development and aging, in a medium term to regulate circadian or estrus cycle, and in a short term to regulate pulsatile GnRH secretion.
    Matched MeSH terms: Sexual Maturation
  15. Roszaman Ramli, Ghazali Ismail
    MyJurnal
    Vaginal agenesis is a rare event occurring at a frequency of 1 case per 4000-10 000 female lives born. The most common etiology of vaginal agenesis is congenital absence of the uterus and vagina called mullerian agenesis (Mayer-Rokitansky-Hauser Syndrome). Although most patients with mullerian agenesis have small rudimentary 2 ‘mullerian bulbs’ without any endometrial activity, 7-8% of these cases possibly have a functioning uterus 3. In vaginal agenesis, genetic females are thought to have persistence of mullerian inhibiting factor MIF, resulting in failure of the vagina and uterus to develop 4. The ovaries, given their separate embryonic source, are normal in structure and function. This condition usually goes undetected until these patients reach puberty, when they start to experience cyclic pelvic pain due to the accumulation of menstrual blood.
    Matched MeSH terms: Sexual Maturation
  16. Shahbazi R, Yasavoli-Sharahi H, Alsadi N, Sharifzad F, Fang S, Cuenin C, et al.
    Int J Mol Sci, 2023 Sep 27;24(19).
    PMID: 37834058 DOI: 10.3390/ijms241914610
    Puberty is a critical developmental period of life characterized by marked physiological changes, including changes in the immune system and gut microbiota development. Exposure to inflammation induced by immune stressors during puberty has been found to stimulate central inflammation and lead to immune disturbance at distant sites from the gut; however, its enduring effects on gut immunity are not well explored. Therefore, in this study, we used a pubertal lipopolysaccharides (LPS)-induced inflammation mouse model to mimic pubertal exposure to inflammation and dysbiosis. We hypothesized that pubertal LPS-induced inflammation may cause long-term dysfunction in gut immunity by enduring dysregulation of inflammatory signaling and epigenetic changes, while prebiotic/probiotic intake may mitigate the gut immune system deregulation later in life. To this end, four-week-old female Balb/c mice were fed prebiotics/probiotics and exposed to LPS in the pubertal window. To better decipher the acute and enduring immunoprotective effects of biotic intake, we addressed the effect of treatment on interleukin (IL)-17 signaling related-cytokines and pathways. In addition, the effect of treatment on gut microbiota and epigenetic alterations, including changes in microRNA (miRNA) expression and DNA methylation, were studied. Our results revealed a significant dysregulation in selected cytokines, proteins, and miRNAs involved in key signaling pathways related to IL-17 production and function, including IL-17A and F, IL-6, IL-1β, transforming growth factor-β (TGF-β), signal transducer and activator of transcription-3 (STAT3), p-STAT3, forkhead box O1 (FOXO1), and miR-145 in the small intestine of adult mice challenged with LPS during puberty. In contrast, dietary interventions mitigated the lasting adverse effects of LPS on gut immune function, partly through epigenetic mechanisms. A DNA methylation analysis demonstrated that enduring changes in gut immunity in adult mice might be linked to differentially methylated genes, including Lpb, Rorc, Runx1, Il17ra, Rac1, Ccl5, and Il10, involved in Th17 cell differentiation and IL-17 production and signaling. In addition, prebiotic administration prevented LPS-induced changes in the gut microbiota in pubertal mice. Together, these results indicate that following a healthy diet rich in prebiotics and probiotics is an optimal strategy for programming immune system function in the critical developmental windows of life and controlling inflammation later in life.
    Matched MeSH terms: Sexual Maturation
  17. Singh GK, Balzer BW, Kelly PJ, Paxton K, Hawke CI, Handelsman DJ, et al.
    PLoS One, 2015;10(11):e0143555.
    PMID: 26599397 DOI: 10.1371/journal.pone.0143555
    The longitudinal relationships of within-individual hormone and anthropometric changes during puberty have not ever been fully described. The objectives of this study were to demonstrate that 3 monthly urine collection was feasible in young adolescents and to utilise liquid chromatography-tandem mass spectrometry assay methods for serum and urine testosterone (T), estradiol (E2) and luteinizing hormone (LH) in adolescents by relating temporal changes in urine and serum hormones over 12 months to standard measures of pubertal development.
    Matched MeSH terms: Sexual Maturation/physiology
  18. Singh, Harbindar Jeet
    Medical Health Reviews, 2009;2009(1):95-133.
    MyJurnal
    Leptin, a 167 amino-acid product of the ob or LEP gene, was first reported in 1994 after a 40-year search that began following the emergence of a mutant strain of mice with hyperphagia, early on-set obesity, and delayed sexual maturation. Since then, leptin deficiency has also been reported in the rat, and more recently in humans. It is secreted constitutively primarily by the white adipose tissue, and in smaller quantities by a number of non-adipose tissues. It acts by binding to specific membrane bound leptin receptors, belonging to the class 1 cytokine receptor family, and activating the JAK-STAT system. Leptin regulates appetite and body weight mainly through its actions on the hypothalamus involving the NPYmelanocortin pathway, and, to a lesser extent, through increased energy expenditure by way of sympathoactivation and increased substrate cycling. Its effects on reproduction, puberty in particular, are mediated through actions on the hypothalamic-pituitary-gonadal axis and on the gonads. Leptin also appears to have permissive roles in CNS development during the neonatal period, bone growth and development, and in haemopoietic and immune functions. Although it was its deficiency state that first led to its discovery, it now appears that the clinical significance of leptin lies not only in the consequences of its deficiency but also when it is in excess as occurs in obesity. Emerging evidence is implicating leptin as a link between obesity associated cardiovascular disease risks and infertility. Besides this, leptin is also being implicated as a growth factor in cancer. The story that started with a search for a body weight regulating factor is now unfolding into one that is revealing roles for leptin that stretch beyond the regulation of appetite and body weight.
    Matched MeSH terms: Sexual Maturation
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