• Korean Journal of Fisheries and Aquatic Sciences
• /
• v.55 no.1
• /
• pp.17-22
• /
• 2022

Successful reproduction in vertebrates necessitates complex interactions along the brain-pituitary-gonad axis, it is determined by gonadotropin releasing hormone produced in the hypothalamus of the brain, gonadotropin synthesized in the pituitary gland, and sex hormone secreted by the gonads. The goal of this study was to secure and test technology for controlling (inhibiting) sexual maturation hormones such as maturation hormones through hormone regulation. We studied the effect on sexual maturation of zebrafish Danio rerio by tamoxifen, anastrozole, exemestane and dopamine 4 kinds of sexual maturation inhibitors to feed and after administration. As a result, 4 kinds of sexual maturation inducing substances were mixed with zebrafish feed, it could be concluded that all of them were effective in inhibiting sexual maturation by reducing mRNA levels of genetic materials related to sexual maturation.

• Women's Health Nursing
• /
• v.24 no.2
• /
• pp.219-228
• /
• 2018

Purpose: The purpose of this study is to evaluate sexual maturation, attitudes toward sexual maturity, and body esteem in the sexual development of Korean elementary-school boys and girls. Methods: A descriptive cross-sectional study was conducted with 399 fifth and sixth graders (192 boys and 207 girls). The data were analysed with a $x^2$ test, t-test, and Pearson correlation coefficients. Results: Among the 207 girls, 70.5% had pubic hair growth, 68.1% had breast development, and 56.0% had a menstrual period. In boys, 59.4% of the 192 subjects experienced the development of external genitalia and 52.6% had pubic hair growth. Sexual maturation was related to grade (boys, t=7.07, p=.008; girls, t=12.76, p<.001), age (t=-2.20, p=.030; t=-4.11, p<.001), height (t=-5.16, p<.001; t=-7.52, p<.001), and weight (t=-2.89, p=.004; t=-5.19, p<.001) in both boys and girls. Girls were more likely to have sexual maturity than boys ($x^2=22.29$, p<.001). Boys showed more positive attitudes toward sexual maturity (t=2.10, p=.036) and higher body esteem (t=2.12, p=.035) than girls. Conclusion: This study shows that sexual maturation, attitude toward sexual maturity, and body esteem in sexual development differ between boys and girls. The findings indicate that it is necessary to develop a tailored sex-education program according to the sex of elementary-school children.

• Journal of Nutrition and Health
• /
• v.40 no.1
• /
• pp.58-68
• /
• 2007

The associations between dietary, body composition and sexual maturation were investigated among Korean girls of pubertal age in this study. Dietary intakes were collected by 3 day food records, body compositions were measured by bio-impedence analyzer and sexual maturation stages were determined with a self-administrated questionnaire using Tanner stages in 1,114 girls 9-13 years of age. Girls were divided into early maturation (EM) and late maturation (LM), based on the comparative maturation stages of breast and pubic hair among the same age groups by months. Subjects were excluded if their stage of maturation could not be divided into early and late groups. EM and LM groups consisted of 42.8% and 38.9% of subjects by breast stage and 67.4% and 22.8% by pubic hair stage. Girls in LM group had significantly lower in height, weight and bone mineral contents (p < 0.05). When nutrient densities of average daily intake of the two groups were compared, folate density was significantly higher among the LM group of breast stages (p < 0.01), and Ca, P, K, Vit. $B_1$, Vit. $B_2$ and folate densities were significantly higher among the LM group of pubic hair stages (p < 0.05). These results show that intakes of some micronutrients differ between children with faster and slower sexual maturation velocities at early pubertal stages. More longitudinal studies are needed to confirm whether such differences are consistent throughout the pubertal period.

• Journal of Embryo Transfer
• /
• v.30 no.2
• /
• pp.83-89
• /
• 2015

The sexual maturation occurred by the changes of steroid hormones was known to sex-dependently and/or age-dependently regulate the lipid metabolism in various animal species. Our current study demonstrates that lipid and its functional fatty acids can be changed depending on the status of sexual maturation. Of the functional fatty acids, ${\gamma}$-linolenic acid (GLA; 18:3n-6) is an important factor for maintaining human health. The purpose of our study was to investigate the level of GLA in mice with different stages of sexual maturation. To this end, the longissimus muscle (LM) of immature (3-week-old) and mature (7-week-old) female mice was analysed for the fatty acid composition by gas chromatography. Furthermore, both gene and protein level of ${\Delta}6$ desaturase (FADS2) which is involved in GLA metabolism by real time PCR and Western blotting, respectively. Mature females showed greater (P<0.05) serum $17{\beta}$-estradiol (E2) level and LM GLA contents than immature group. The mRNA and protein levels of FADS2, which converts precursor linoleic acid into GLA, were higher (P<0.05) in mature female mice than in immature mice. In conclusion, these results show that sexual maturation of female mice induces GLA and FADS2 contents in LM.

• Research in Community and Public Health Nursing
• /
• v.23 no.4
• /
• pp.405-414
• /
• 2012

Purpose: The purpose of this study was to examine the sexual maturation, body image, and self-esteem of Korean elementary school girls with symptoms of precocious puberty compared to those with no symptoms of precocious puberty. Methods: The subjects were 309 girls of lower grades in elementary school. Tanner's Sexual Maturation Rating (SMR), Self Image Scale, and Self-esteem Scale were utilized to determine the presence of symptoms of precocious puberty, body image, and self esteem. Collected data were analyzed by Chi-square test, independent t-test, and one-way ANOVA using the SPSS/WIN 17.0 program. Results: The percentage of the girls with breast development was 14.9%. Breast development usually began in the third grade (56.5%). Of the subjects, 0.3% were experiencing menstruation. Breast development was related to grade, age, height, weight, and a cause of worry. There was a significant difference of body image between girls with breast development in the first grade and in the second grade. Conclusion: An effective intervention that can improve the self-image of children with symptoms of precocious puberty should be developed to prevent and treat physical and mental problems related to sexual maturation.

• Journal of Life Science
• /
• v.27 no.10
• /
• pp.1097-1103
• /
• 2017

For the artificial induction of the sexual maturation of Anguilla japonica, salmon pituitary extract (SPE) is continuously injected into females, and the eggs obtained from artificial sexual maturation are artificially fertilized with sperms and hatched. However, repeated injection of SPE in the abdominal cavity causes tremendous stress in females, which may prevent their complete sexual maturation and reduce the immune system function, ultimately resulting in death. In addition, the poor quality of the ovulated eggs can reduce the hatching and survival rate of larvae. In the present study, sexual maturation of females was induced by inserting an osmotic (OS) pump containing hormone analogs known to effectively induce sexual maturation into the abdominal cavity of female eels, and the effect of the OS pump on the induced sexual maturation was investigated. Our study results showed that the gonadosomatic index (GSI) was significantly higher in the fish subjected to SPE injection than those subjected to human chorionic gonadotropin (hCG), gonadotropin-releasing hormone analog (GnRHa), and methyl testosterone (MT) injections, either separately or in combination. In addition, a histological analysis showed that the oocytes in the SPE OS pump groups were more mature (entered the nuclear shift stage) than those in the other groups. These results suggest that an osmotic pump containing hormone analogs can be used to induce sexual maturation in female A. japonica artificially.

• Asian-Australasian Journal of Animal Sciences
• /
• v.20 no.1
• /
• pp.19-24
• /
• 2007

Covariance components and genetic parameters of weekly live body weight from hatching to six weeks of age and age of sexual maturation were estimated in a laying type Japanese quail line. The univariate and bivariate animal model analysis included hatching group and sex as fixed effects. Each trait was analysed with animal as random effect to fit the additive direct effect. Additional random effects incorporated in the models were changed according to the trait examined. The best model for a trait was chosen based on a likelihood ratio test, comparing the models with and without maternal additive genetic and maternal permanent environmental effects. Heritability estimates of live-weight at hatch and one to six weeks of age with their standard errors were 0.22${\pm}$0.088, 0.39${\pm}$0.099, 0.31${\pm}$0.086, 0.38${\pm}$0.056, 0.46${\pm}$0.055, 0.50${\pm}$0.059, and 0.56${\pm}$0.062, respectively. Direct heritability value of age of sexual maturation was moderate (0.24${\pm}$0.055). The variances due to permanent environmental effect of dam after one week of age and maternal genetic effect after two weeks of age were not important sources of variation. The correlations between direct and maternal genetic effects were negative and ranged from high to moderate values (-0.21 to -0.83). Among the weekly live weights, genetic correlations were generally high between not only successive but also early and late weightings. It suggests that selection for final weight may be based on early weight records. Genetic correlations between age of sexual maturation and live weights were low, favourable but had high standard errors. These results indicate that selection for high weight will potentially result in lower age of sexual maturation only with accurate determination of breeding values.

• Journal of Aquaculture
• /
• v.16 no.4
• /
• pp.245-251
• /
• 2003

Sexual maturation and gametogenic cycle of the hard shelled mussel, Mytilus coruscus were investigated by means of histological method. Specimens were collected monthly in Hansan Bay of south coast, Korea from January to December 2002. Sex of the clam was dioecious. The gonads are composed of a number of gametogenic follicles. The gonad index (GI) was reached the maximum in February (3.40), and the minimum in August (1.18). The monthly variation of condition index (CI) coincides with gonad index. The main spawning occurs between February and March. The gametogenic cycle of the clam could be divided into six stages: resting (August to November), multiplicative (November to December), growing (December to January), maturation (January to February), partially spent (February to April) and completely spent/degenerative stage (April to July). Sex ratio (♀/♂) was 1:0.96.

• Journal of Marine Life Science
• /
• v.1 no.1
• /
• pp.41-49
• /
• 2016

Kisspeptin (Kiss) and its cognate receptor, kisspeptin receptor (KissR; G protein coupled receptor 54, GPR54), have recently been recognized as potent regulators of reproduction in teleosts. Additionally, leptin plays an important role in energy homeostasis and reproductive function in teleosts. The purpose of this study was to examine differences in the concentration of the hormones of the Kiss/KissR system and leptin and the expression of their underlying genes, all of which are involved in the sexual maturation of female goldfish, Carassius auratus, following treatment with Kiss. The expression levels of KissR increased after the Kiss injection. Furthermore, the peptide hormone leptin also increased after the injection (in vivo and in vitro). Additionally, the expression of GnRH and GTHs (GTHα, FSHβ, and LHβ) increased in the brain and pituitary (in vitro and in vitro). These results support the hypothesis that Kiss plays important roles in the direct regulation of the hypothalamus-pituitary-gonad axis and leptin in goldfish. Therefore, we suggest that Kiss system gene expression is correlated with energy balance and reproduction.

• Journal of fish pathology
• /
• v.16 no.2
• /
• pp.125-129
• /
• 2003

Conncxin (Cx) is an important and essential protein induction of oocyte maturation, which is present in almost all mammalian tissucs except cirulating blood cells and adult skeletal museles. In this study, goldfish Cx43 cDNA sequence is available in GenBank under the accession number AB078505. Homology analyses using the GenBank and EMBL general database searches indicated that goldfish Cx43 cDNA has a high homology with carp Cx43 (95.1% identity), zebrafish Cx43 (90.5% identity), and chicken Cx43 (81.9% identity). Goldfish Cx43 is similar to the Cx family in its general features, and all the typical Cx consensus sequences are also found. Moreover, significantly increased Cx43 transcrpts were observed in mature goldfish (GSI; 18.3-21.7) pituitary and ovary when compared with immature goldfish (GSI; 4.9-6.0). Cx43 transeripts were weakly detectrd in both liver and kidney of immature and mature goldfish. There is possible that Cx43 nctivity was relation to oocyte maturation in the goldfish.