• Korean Journal of Health Education and Promotion
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• v.17 no.1
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• pp.19-39
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• 2000

The purpose of this study was to examine the prevalence and correlated factors of sexual behavior among high school students in Seoul A sample of 233 male and 248 female high school students were analyzed using cross-tabulation and logit regression models. Correlated factors examined include type of school, level of mothers education, perceived living status of family, whether family has two parents or not, and whether students have ever lived away from the family, whether students received reproductive health education at school and whether they have friends with sexual experience, whether students have ever smoking and alcohol drinking. The prevalence of alcohol drinking was 73% among boys and 55% among girls and the prevalence of smoking was 64% of boys and 40% of girls, whereas the prevalence of sexual activity was 27% among boys and 15% among girls. Risk taking was more prevalent among boys than among girls. Multiple risk taking behavior was common for both boys and girls. Students who did not have two parents were more likely to engage in risk taking behavior than those who had two parents. For both boys and girls, the factor that affects their own sexual activity most was having a friend who was sexually active and having an experience of living away from their family also increases the odds. For girls, the factor that affects having experience of alcohol drinking and smoking. Receiving reproductive health education at school had no effect on students sexual behavior. Much higher risk taking behavior with sexual behavior among students in Seoul implies that the overall prevalence of risk taking behavior among high school students was likely to rise as South Korea continues its modernization. In-school and community health education programs need to be modified to be effective in protecting students from risk taking sexual behavior.

• Asian Pacific Journal of Cancer Prevention
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• v.15 no.24
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• pp.10603-10605
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• 2015

Background: The Prostate cancer is the 2nd most common cancer worldwide for males, and the 5th most common cancer overall, with an estimated 900,000 new cases diagnosed in 2008 (14% of the total in males and 7% of the total overall) aim of this study was to assess some of the most proposed environmental factors influencing the incidence of prostate cancer among Iranian men. Smoking, opioids, occupation and living location were considered as studied risk factors of the prostate cancer in this research. Material and methods: Two groups of affected men with prostate cancer and controls aged 50-75 years referred to medical clinics were subjects in this case-control study. Living and working place, smoking and drug consuming habits were assessed for any associations with prostate cancer. Results: The largest number, of patients, in order, belonged to Tehran, provincial capitals, major industrial cities, small towns and villages, respectively. The disease showed links with smoking and drugs with a significant difference between controls and patients (P value <0.0001). Conclusions: Our recent evidence duplicates previously done researches confirming the serious adverse effects of smoking and drugs on the prostate cancer occurrence in Iranian men. Living place bearings some hazardous behaviors which increases the rate of diseases as well as advanced chance for associated cancers like prostate.

• Journal of Animal Science and Technology
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• v.62 no.6
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• pp.875-883
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• 2020

This study was conducted to investigate the effects of group-housing facility (GHF), compared to an individual confinement stall (CON), on the reproductive performance, behavior, and stress hormones of gestating sows. A total of 50 primiparous sows (Landrace × Yorkshire) were randomly allocated into either CON (n = 25) or GHF (n = 25) during the gestation period. One week before parturition, the sows were transferred into conventional farrowing crates, and cross-fostering was conducted within 1 d of delivery. Blood was collected for analyses of stress indices at 75 d of gestation and postpartum. Reproductive performance was estimated during the period of birth to weaning. Behavior patterns were identified at 90 d of gestation. Litter size was not different between the CON and GHF treatments. Weaning to estrus interval, however, tended to be lower in the GHF than in the CON (p < 0.1). Activity, treating, belly nosing, and exploring behaviors were observed only in the GHF group, whereas rubbing was shown only with the CON. Serum cortisol concentration was lower in the GHF than in the CON at 75 d of gestation (p < 0.05). Sows housed in the GHF showed lower epinephrine and norepinephrine concentrations than those housed in the CON at postpartum (p < 0.05). The GHF sows demonstrated more natural behavior characteristics associated with stress relief than the CON sows with no adverse effects on reproductive performance. Therefore, these results suggest that GHF could be applied as an alternative housing facility to improve animal welfare on swine farms.

• Toxicological Research
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• v.17
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• pp.313-317
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• 2001

The Ministry of Health and Welfare of Japan has set up six research groups concerning the endocrine disrupting chemicals. One of these projects was "A study on development of testing methodology for health effects due to exposure of environmental endocrine disruptors". In this paper, three topics are described. In OECD collaboration for pre-validation of uterotrophic assay, the most sensitive response to ethnyl estradiol was noted in the ovarectomized rats treated subcutaneously for 7 days. Secondly, it was suggested that changes of the serum $\alpha_{2u}$-globulin level may be a sensitive parameter for detecting the estrogenic activities of chemicals. Finally, development of the sexually dimorphic nucleus of preoptic area in the brain oj male rats was inhibited by the treatment with estrogenic chemicals, and their masculine behaviors and reproductive abilities were impaired after sexual maturation. In conclusion, these parameters are considered to be sensitive endpoints for testing estrogenic chemicals.chemicals.

• Development and Reproduction
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• v.13 no.2
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• pp.79-87
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• 2009

Due to its well-known function in parturition and milk ejection, oxytocin (OT) has been considered as a 'female neurohypophyseal hormone'. Recent studies, however, clearly indicate that OT has some local roles in male reproduction via both central and peripheral routes. In experimental rodents, OT is released within distinct brain regions in response to social stimuli, and the brain OT receptor (OTR) mediated actions were strongly involved in the regulation of a variety of male behaviors such as mating-associated behaviors. In particular, OT and/or OTR knockout mice provide important clues about the molecular regulatory mechanism of the socio-sexual behaviors. Several lines of evidence also show that OT is synthesized within rodents testis, epididymis and prostate, and the presence of OTRs in these organs. In rodent testes, OT might have a role in the modulation of steroidogenesis via stimulation of the conversion of testosterone (T) to dihydrotestosterone (DHT) by 5alpha-reductase. Similar effects of OT on this androgen conversion were observed in epididymis and prostate suggesting the OT's modulatory role, such as contractility induction, in these androgen-dependent organs. In this context, further investigations on the OT's role in male CNS and reproductive organs are likely to provide better understanding on the complex socio-sexual behaviors and a platform for development of therapeutics to treat some psychological and/or andrological problems.

• Journal of Preventive Medicine and Public Health
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• v.39 no.5
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• pp.389-396
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• 2006

Objectives: A community-based, cross-sectional survey was conducted to determine theprevalence of osteoporosis and to evaluate the effects of body composition, health behaviors and reproductive history on bone density in postmenopausal women. Methods: The study subjects were 362 postmenopausal women, aged 45 years old or over, who were invited to the hospital. Information on their socio-demographic characteristics and the potential risk factors such as their past medical history, smoking, alcohol intake, exercise, diet and menstrual/reproductive histories were collected by trained interviewers. Weight, height, the body mass index ($kg/m^{2}$), and body composition variables were measured. Bone mineral density of the lumbar spine was measured by dual energy X-ray absorptiometry (DXA). Results: The prevalence of osteoporosis was 30.6% in the $45{\sim}64$ years old women, 52.5% in the elderly women aged $65{\sim}74$, and 68.7% in the women aged 75 years or over. After adjustment for the effect of potential covariates, those women in the highest 25% (4th quartile) of the lean body mass are less likely to have osteoporosis (aOR=0.31, 95% CI=0.12-0.76), compared with the lowest quartile group. More parity also had significantly detrimental effects on osteoporosis. Conclusions: These findings suggest that the prevalence of osteoporosis in postmenopausal women increased with age from 46.3% of those aged 45-64 to 68.7% for those aged 75 and over. Lean body mass and parity appeared significant contributor to bone mineral density in postmenopausal women in this population.

• Animal cells and systems
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• v.13 no.1
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• pp.71-78
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• 2009

To clarify the reproductive function of vibration signals in Hynobius, which has externally fertilized eggs, we quantitatively analyzed the body and tail undulations of male Korean salamanders (Hynobius leechii) in sixteen mating events. One large and one small male, and one female were used in each mating event. We analyzed behaviors recorded over a total of 3 hrs for each mating event; 2 hrs before and 1 hr after female's oviposition. Males touched females using their snouts or body trunk throughout the entire mating periods, but females touched males increasingly more after approximately 1 hr before oviposition. Males conducted body undulations more than 50 times per 10 minutes at a mean frequency of 0.64 Hz. Large males conducted more body undulations than small males, particularly on the tree twig where females attached their egg sacs. Males responded to other males' body undulation throughout the mating period by orienting their head towards, approaching, and touching the undulating male. Females only responded for about 10-20 min before ovipositing, and most responses were directed to the large male's body undulation. Males conducted tail undulations 3.0 times per 10 min at a mean frequency of 1.7 Hz and most tail undulations occurred after one male bit the other male. These results suggest that body undulations function in both male-female and male-male interactions, while tail undulations mainly functions in male-male competition. Also, male H. leechii appear to actively attract females, while females respond to the males only at times close to oviposition.

• Biomolecules & Therapeutics
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• v.4 no.4
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• pp.297-300
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• 1996

LBD-001, a recombinant human interferon $\gamma$ produced by genetically engineered yeast as a host system, was administered intraperitoneally to Sprague-Dawley male rats from premating to mating period at least for 60 days and to female rats from at least for 2 weeks before mating to early gestation period (from day 0 to 7 of gestation) at dose levels of $0.35\times10^6, 0.39\times10^6, and 1.38\times10^6$ I.U./kg/day. In the positive control group, ethynylestradiol ($EE_2$; 40 $\mu\textrm{g}$/kg/day) was subcutaneously administered only to female rats during the early gestation period. Effects of the test agents on reproductive performances of the male or female rats and embryonic development were as followings; (1) No significant changes by the treatment of LBD-001 were observed in general behaviors, body weight, food and water consumption, and necropsy of parent animals. However, significant decreases of body weight, food consumption, and water consumption were observed in ($EE_2$ -treated female rats. (2) Mating performances and fertility of parent animals were not significantly affected by the treatment of LBD-001. In ($EE_2$ -treated females, however, the fertility was completely inhibited. (3) No changes in resorption rate and external abnormality of F1 fetuses were observed by the treatment of LBD-001. The results show that LBD-001 at the dose of $1.38\times10^6$ I.U./kg/day or less does not affect general toxicity and reproductive function of parent animals and embryonic development of F1 fetuses.

• Korean Journal of Environment and Ecology
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• v.30 no.6
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• pp.977-985
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• 2016

The captive breeding program of the Reeve's turtle (Mauremys reevesii), which is designated as an endangered category II species by the Korean Ministry of Environment, has developed, but the reproductive physiology of the species is still not fully understood. In this study, we investigated seasonal changes in the sex steroid levels, the number and size of follicles and eggs and male-female interactive behaviors of hibernated and non-hibernated turtles between November 2014 and October 2015. Plasma estradiol level in females increased from July and peaked in the period from August to October. Plasma testosterone level in males peaked between August and September and was the lowest in March, although there were some variations depending on the patterns of hibernation. Hibernated females had fully developed eggs between early May and middle July and laid eggs between early June and late July, but non-hibernated females had eggs between early April and early June and also between middle August and late November, and laid eggs in early June, mid-October, and early February. These results suggest that hibernation could be essential for normal follicular and egg developments. Male-female interactive behaviors including courtship intensified from late August and peaked in October and November. Our findings suggest that mating period of this species is directly related to increased steroid hormone levels, but follicular and egg developments in females are not. Our results could be very useful to the successful operation of captive rearing programs of the endangered Reeve' sturtles.

• Journal of Ecology and Environment
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• v.31 no.1
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• pp.1-7
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• 2008

In this minireview we focus on how males may exploit female's sensitivity to predation risk in the context of mating. It has been shown in studies on guppies and jumping spiders that in response to altered female behaviors, which are adaptations to the unfavorable environment and a consequence of females' higher sensitivity to predator's presence as well as females' higher predation risk, males can adopt condition-dependent mating tactics. It appears that in such cases males do not modify their reproductive behavior directly in response to their own perception of predation risk, but indirectly in response to changes in female behavior induced by predator presence. It has also been recently shown in crabs that males can exploit female behavior by creating safer habitat spots, which increases the male mating success. Hence all the evidence suggests that males not only respond to female sensitivity to the natural variation in predation risk, but that males can also exploit female behavior by altering the environment. As a logical extension of these findings, we present a hypothesis that in certain conditions males can manipulate the environment in order to increase the predation risk and to induce female behaviors that enhance the male's mating success with the increased predation risk. We propose that such a manipulation to increase predation risk is expected to evolve in males of species with a strong sexual conflict and female-biased predation risk. Although empirical evidence has not been yet shown, initial observations in a water strider species in Korea, Gerris gracilicornis, seem to support this hypothesis.