• Toxicological Research
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• v.20 no.2
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• pp.131-136
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• 2004

3-Monochloro-1,2-propanediol(3-MCPD) is a toxic compound, often present in different foods containing acid hydrolyzed(AH) protein, like seasonings and savory food products. The purpose of the present study was to investigate the effects of 3-MCPD on male fertility, sperm and testosterone secretion. In vivo male fertility test was performed for observing the adverse effects of 3-MCPD on the function of male reproductive system and pregnancy outcome. 0.01, 0.05, 0.25, 1 and 5 mg/kg b.w. of 3-MCPD was given daily by gavage to groups of 15 adult male SD rats for 4 weeks. At the end of pre-treatment period, males were mated overnight with normal females. Following morning, males demonstrating successful induction of pregnancy were sacrificed on that day to assess sperm parameters and histopathology of reproductive organs. The resulting pregnant females were sacrificed on day 20 of gestation to evaluate pregnancy outcome. As a result, four-week paternal administration with 3-MCPD resulted in adverse effects on male fertility and pregnancy outcome without remarkable histopathological changes in testes and epididymides; sperm motility, copulation index and fertility index were markedly decreased in the treated group and numbers of live fetuses showed steep dose-response curves. Also, spermatogenesis was investigated in this experiment. However, no effect was observed on production of sperm in testes treated with 3-MCPD for 4 weeks. Hormone assay was performed for observing the effects of 3-MCPD on testosterone and luteinizing hormone (LH) in blood and testes of male SD rats and cultured primary Leydig cell. In result, significant changes of related hormones did not observed by treatment of 3-MCPD. These results indicated that paternal treatment with 3-MCPD induced spermatotoxic effect, which caused an antifertility on male.

• Development and Reproduction
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• v.6 no.1
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• pp.45-54
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• 2002

Reproductive activity of golden hamsters(Mesocricetus auratus) is regulated by the photoperiod. They are sexually active in summer and inactive in winter. Melatonin, a pineal hormone, has been known to mediate sexual activities in seasonal breeding animals. Melatonin receptor was recently identified in several animal species including hmm. But little has been known about it in relation to the reproductive activities of golden hamsters. By using reverse transcription polymerase chain reaction(RT-PCR) methods, a portion of the melatonin receptor gene(309 nucleotides) was identified in golden hamsters. The nucleotide sequence of the melatonin receptor and the amino acid sequence deduced were compared to those reported in other animals. Melatonin receptors were obviously detected in hypothalamus, pituitary containing pars tuberalis, blood, and spleen. Although the testicular weights and the levels of reproductive hormones were dramatically affected by photoperiods, the expression of melatonin receptor was not markedly changed by them. These results suggest that the action of melatonin in regulating reproduction might be mainly due to the affinity of melatonin receptor rather than the density fi melatonin receptor.

• Clinical and Experimental Reproductive Medicine
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• v.23 no.1
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• pp.87-94
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• 1996

For evaluating the suitability of human follicular fluid(HFF) as protein supplement in ART, this preliminary study was performed to examine the maturation promoting activity of HFF on mouse follicular oocytes in vitro. Mouse follicular oocytes were collected from ovaries of 21-28 day old ICR mice by puncturing the antral follicles with fine needle at 48 hours after PMSG injection. The oocytes were rinsed and cultured in modified Whittingham's $T_6$ medium containing purines or dbcAMP to maintain meiotic arrest, and different concentrations of HFF were added into the culture medium to examine the effect of HFF on releasing the oocytes from the suppressive influence of the meiotic inhibitors. As a control for HFF, the maturation promoting activity of human fetal cord serum(HFCS) was investigated and compared with the activity of HFF. While HFF was separated, by molecular weight(M.W), into high M.W. fraction(M.W>30,000) and low M.W. fraction(M.W<30,000) and the effects of the fractions on meiotic resumption were investigated in the presence of the meiotic inhibitors. Also hormone analysis was performed to compare the content of hormones in HFF with that in HFCS. Same concentrations of HFF and HFCS induced similar germinal vesicle break down(GVBD) rates of the oocytes meiotic arrested by purines(4mM hypoxanthine+0.75mM adenosine), but the extrusion rate of 1st polar body(PB) of the oocytes cultured in HFF(65.0%, P<0.05) was significantly higher than that(51.6%) in HFCS. While, in the presence of 200 M dbcAMP, the maturation promoting activity of HFF (GVBD: 70.5%, $p<10^{-6}$; 1st PB extrusion: 67.1%, $p<10^{-3}$) was significantly greater than that of HFCS(GVBD: 35.2%; 1st PB extrusion: 41.1%). The oocytes cultured in the fraction of HFF containing high M.W. components showed higher meiotic maturation rates than the oocytes cultured in the low M.W. fraction of HFF. Gonadotropins and $E_2$ were known to improve the completion of maturation changes, and the levels of these hormones were higher in HFF than in HFCS. Therefore, HFF was more effective than HFCS to use for promoting meiotic resumption of mouse oocytes in vitro.

• Korean Journal of Ichthyology
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• v.23 no.4
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• pp.261-268
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• 2011

To clarify the annual reproductive cycle of the Korean perch, Coreoperca herzi, the seasonal changes in gonadosomatic index (GSI), hepatosomatic index (HSI), histological aspects of gonad and liver, and plasma levels of sex steroid hormones were investigated from June 1994 to April 1996. The annual variations of GSI and HSI were positively related to the plasma levels of sex steroid hormones. Estradiol-$17{\beta}$ (E2) and testosterone levels were raised during the April to May. Based on the related results, annual reproductive cycle of the fish could be divided into five successive stages; 1) Growing stage (from February to March: GSI was increased rapidly and oocytes with yolk vesicle was increased. Nucleus migrates toward the animal pole. Spermatids were activated from the epithelial tissue of lobuli). 2) Maturation and spawning stage (from April to June: Oocytes were accumulated yolk globules. Active spermatogenesis was observed). 3) Degeneration or stagnation phase (from July to August). 4) Recovery phase (from September to November) and 5) resting phase (from December to January). The main spawning period was in May.

• Korean Journal of Fisheries and Aquatic Sciences
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• v.35 no.6
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• pp.614-620
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• 2002

The sea bass, Lateoiabrax japonicus is a highly valued fish in aquaculture in South Korea. For establishment of seedling production of sea bass,1 japonicus, we examined change of gonadal development and plasma steroid levels of sea bass reared in indoor tank. Male matured unsimultaneously faster than females and spawning of females took place between the end of January and March. After the spawning period, and until the following January, all the females were in preyitello genesis and in some males, spermatogenetic activity restarted gradually. In October, under reducing photoperiod, cortical alveoli appeared in growing oocyte and the development of spermatogenesis greatly increased. Between October and february, vitellogenesis and spermatogenesis occurred respectively in female and male and gonadosomatic index increased from 4.31 to $24.07\%$ in female and upper 6o/o in male. Also, two sex hormones were analyzed during the course of a reproductive cycle in the sea bass: plasma levels of the gonadal steroid testosterone (T) and estradiol-l7$\beta$ (E_{2}). Variation of the plasma concentrations of T and E, appeared to depend on gonad stages. Plasma T and E, levels were high from November to January, suggesting that an sufficient gonadal stimulation by both hormones may undergoing a processes for the formation of sperm and oocyte.

• Clinical and Experimental Reproductive Medicine
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• v.8 no.2
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• pp.1-11
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• 1981

The quantitative analyses of the phosphatase activity in the endometrium of the rat ovariectomized on Day 2 of pregnancy was carried out in comparison with the intact one, in order to investigate the hormonal dependency of the uterus prior to the implantation, and to study the phosphatase activity in the endometrial tissues in vitro incubated in different acidity of the medium. The results obtained were as follows: 1. The activity of the total phosphatase was the highest at Day 3 of pregnancy of the intact animals irrespective of acidity of the medium. However, the ovariectomized rat showed its peak somewhat delayed. The time of the highest activity of the enzymes was matched with the time of high secretion of the ovarian hormones. 2. The activity of acid phosphatase in the endometrium was twice or four times as much high as that of neutral or alkaline phosphatase, respectively. 3. The activity of alkaline phosphatase was rather steady in Day 3 through Day 5 of the pregnancy of the rat intact or ovariectomized but with low level compared to those of other phosphatase. 4. The present re~lt indicated more important role by $Mg^{2+}$-dependent phosphatase than by $K^+$-dependent one for the preparation for decidualization.

• Development and Reproduction
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• v.25 no.3
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• pp.157-171
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• 2021

To determine whether the reproductive processes of sea bass, Lateolabrax japonicus, proceed normally after transportation from an outdoor net-cage into indoor tanks, we examined changes in the gonadosomatic index (GSI), histological gonadal tissue, and plasma levels of sex hormones (testosterone and estradiol-17ß) during their annual reproductive cycle. We also measured maturation and spawning across two sea water salinity levels (full and low salinity). Fecundity was estimated by the relationship between egg number and body size in female sea bass. Monthly changes in the GSI, histological gonadal tissues, and oocyte size showed both male and female sea bass reach final maturation in January and February, respectively, indicating that the spermiation of males occurs earlier than the spawning of females. The histological results indicated that the sea bass is a multiple spawner, similar to many marine teleosts, exhibiting group-synchronous oocyte development. Female maturation and spawning were enhanced in lower salinity seawater (29.6-31.0 psu) compared to that of normal salinity (34.5-35.1 psu). These results confirm that sea bass reproduction can occur successfully in captivity and imply that fertilized eggs can be collected from February to March. Additionally, our results show that lower salinity enhances oocyte maturation and spawning of female sea bass.

• Journal of Veterinary Clinics
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• v.30 no.3
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• pp.178-185
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• 2013

This study evaluated the effects of milk yield on the postpartum health and reproductive performance of dairy cows. In total, data were collected from 1,060 cows on six dairy farms, including their milk production, body condition score (BCS), postpartum disorders, and reproductive performance. The lactation data were grouped based on the 305-day milk yield into control (< 10,000 kg, n = 445) and high milk yield (${\geq}$ 10,000 kg, n = 615) groups. The milk fat and protein, and BCS were lower during the first 5 months postpartum in the high milk yield group compared with the control group (p < 0.01). Ovarian cysts were more frequent (p < 0.0001) in the high milk yield group (28.6%) than in the control group (15.3%), whereas endometritis tended to be less frequent in the high milk yield group (29.6%) than in the control group (35.1%, p = 0.06). A higher proportion of cows tended to receive reproductive hormones (p = 0.06) in the high milk yield group (62.4%) than in the control group (56.6%). The probability of a pregnancy after first insemination tended to be lower (odds ratio = 0.78, p = 0.07) in the high milk yield group (30.2%) than in the control group (35.2%). Furthermore, the hazard of pregnancy by 210 days in milk was lower in the high milk yield group (hazard ratio = 0.84, p = 0.04) than in the control group, which resulted in a 20-day increase in the median interval to pregnancy. In conclusion, high milk yield was related to lower milk fat and protein, lower BCS, an increased incidence of ovarian cysts, and increased use of reproductive hormones, which resulted in decreased reproductive performance of dairy cows.

• Development and Reproduction
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• v.6 no.1
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• pp.55-66
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• 2002

Embryonic stem cells(ES cells) are derived from the inner cell mass(ICM) of blastocysts, which have the potentials to remain undifferentiated, to proliferate indefinitely in vitro, to differentiate into the derivates of three embryonic germ layers. ES cells are an attractive model system for studying the initial developmental decisions and their molecular mechanisms during embryogenesis. Additionally, ES cells of significant interest to those characterizing the various gene functions utilizing transgenic and gene targeting techniques. We investigated the effects of reproductive hormones, gonadotropins(GTH) and steroids on the induction of differentiation and expressions of their receptor genes using the newly established mouse ES cells. We collected the matured blastocysts of inbred mice C57BL/6J after superovulation and co-cultured with mitotically inactivated STO feeder cells. After 5 passages, we confirmed the expression alkaline phosphatase(Alk P) activity and SSEA-1, 3, 4 expressions. The protocol devised for inducing ES differentiation consisted of an aggregation steps, after 5 days as EBs in hormone treatments(FSH, LH, E$_2$, P$_4$, T) that allows complex signaling to occur between the cells and a dissociation step, induced differentiation through attachment culture during 7 days in hormone treatments. Hormone receptors were not increased in dose-dependent manner. All hormone receptors in ES cells treated reproductive hormones were expressed lower than those of undifferentiated ES cell except for LHR expression in E$_2$-treated ES cells group. After hormone induced differentiation, at least some of the cells are not terminally differentiated, as is evident from the expression of Oct-4, a marker of undifferentiated. To assess their differentiation by gene expression, we analyzed the expression of 7 tissue-specific markers from all three germ layers. Most of hormone-treated group increased in the expression of gata-4 and $\alpha$ -fetoprotein, suggesting reproductive hormone allowed or induced differentiation of endoderm.

• Korean Journal of Poultry Science
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• v.45 no.4
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• pp.245-252
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• 2018

This study investigated the effect of LED light wavelength (color) on reproductive hormones and egg production of brown laying hens raised on floor. Red, blue, green and white colors of LED light were four treatments with four pens per treatment. One hundred forty four Hy-line brown laying hens (47 wks old) were allocated in a floor pen for six weeks trial. Egg production, egg quality, yolk cholesterol and hormones ($17{\beta}$-estradiol, progesterone) concentrations in plasma and oviduct were analyzed. Egg production of red group was higher (P<0.01) than that of green group. Haugh unit of eggs from red group was higher (P<0.01) than that of blue and green groups. Egg weight of green group was heavier (P<0.05) than that of red group. Shell of blue group was stronger (P<0.05) than that of red and white groups. Shell color of white group was browner (P<0.01) than that of blue and green groups. Yolk cholesterol of red group was higher (P<0.01) than that of others. Plasma $17{\beta}$-estradiol of red group was higher (P<0.05) than that of others at $3^{rd}$ week, but that of white group was highest (P<0.05) at $6^{th}$ week. Oviduct progesterone of green group was higher (P<0.01) than that of others. The result showed that the LED colors affect the reproductive hormone concentrations, egg production, egg weight and egg quality. This study suggested that red LED would be the most appropriate color for floor raising brown laying hens to sustain the egg production when it begins to decline with aging.