• Applied Microscopy
• /
• 제23권1호
• /
• pp.77-90
• /
• 1993

The mechanism by which blastocysts implant to uterine endometrium has not been clearly understood. In the present study, the following question was investigated: how are hormonal levels changed and how is uterine endometrium morphologically changed? Results obtained are as follows: Concentrations of serum estradiol and progesterone were significantly increased on day 4 and 5 of pregnancy. Uterine concentrations of PGE and $PGE_{2a}$ were sharply increased on day 1 and maintained similar concentrations thereafter, reaching the maximum on day 5. Both prostaglandins (PGs) concentrations were gradually decreased thereafter. Furthermore, concentrations of PGs in implant sites were greater than those in non-implant sites. PBR (pontamine blue reaction) in uterine endometrium was positive on day 6 of pregnancy, indicating that vascular permeability was increased. Edema and changes in structure of cell components were pronounced in stroma where PBR was developed. Moreover, these were more prominent in implant sites than non-implant sites. These results suggest that uterine PGs as well as steroid hormones increase during implantation in rats and these hormones might be involved in the process of implantation by modulating vascular permeability and the fine structures of uterine endometrial cells.

• Toxicological Research
• /
• 제26권4호
• /
• pp.301-313
• /
• 2010

Growth promoters including hormonal substances and antibiotics are used legally and illegally in food producing animals for the growth promotion of livestock animals. Hormonal substances still under debate in terms of their human health impacts are estradiol-$17\beta$, progesterone, testosterone, zeranol, trenbolone, and melengestrol acetate (MGA). Many of the risk assessment results of natural steroid hormones have presented negligible impacts when they are used under good veterinary practices. For synthetic hormonelike substances, ADIs and MRLs have been established for food safety along with the approval of animal treatment. Small amounts of antibiotics added to feedstuff present growth promotion effects via the prevention of infectious diseases at doses lower than therapeutic dose. The induction of antimicrobial resistant bacteria and the disruption of normal human intestinal flora are major concerns in terms of human health impact. Regulatory guidance such as ADIs and MRLs fully reflect the impact on human gastrointestinal microflora. However, before deciding on any risk management options, risk assessments of antimicrobial resistance require large-scale evidence regarding the relationship between antimicrobial use in food-producing animals and the occurrence of antimicrobial resistance in human pathogens. In this article, the risk profiles of hormonal and antibacterial growth promoters are provided based on recent toxicity and human exposure information, and recommendations for risk management to prevent human health impacts by the use of growth promoters are also presented.

• 한국수산과학회지
• /
• 제47권6호
• /
• pp.882-887
• /
• 2014

We studied oocyte steroidogenesis in blacktip grouper Epinephelus fasciatus ovarian follicles during vitellogenesis. Vitellogenic oocytes with average diameters of 0.45, 0.48 and 0.50 mm were incubated in vitro in the presence of $[^3H]17{\alpha}$-hydroxyprogesterone as a precursor. The steroid metabolites were analyzed using thin layer chromatography (TLC), high performance liquid chromatography (HPLC), and gas chromatography-mass spectrometry (GC/MS). The major metabolites in the vitellogenic oocytes were androstenedione ($A_4$), testosterone (T), estradiol-$17{\beta}$ ($E_2$), and estrone ($E_1$). The metabolites of androgen ($A_4$ and T) were higher in the 0.50-mm oocytes than in the 0.45- and 0.48-mm oocytes, while the estrogen metabolites (E2 and E1) were lower in the 0.50-mm oocytes. These results suggest that 0.50-mm oocytes are fully vitellogenic following initiation of the maturation process.

• 한국양식학회지
• /
• 제20권3호
• /
• pp.154-159
• /
• 2007

Manchurian trout (Brachymystax lenok) is an endangered fish species in East Asia including the Korean peninsula. To establish a method for artificial propagation and to improve our understanding of the reproduction in the species, we have produced recombinant gonadotropins, follicle-stimulating hormone (r-mtFSH) and luteinizing hormone (r-mtLH), which may play central roles in reproductive activities. In the present study, the biological activities of the recombinant hormones were analyzed by gonadosomatic index (GSI), ovarian follicle diameter, and sex steroid levels in mature rainbow trout (Oncorhynchus mykiss). In the 6th day post-injection, FSH-injected fish were slightly decreased in the GSI value, although there were no significant differences among those of control, r-mtFSH, and r-mtLH treatments. Injection of the r-mtFSH increased follicle diameters significantly as compared with those of control- and r-mtLH-injected fish. The plasma steroid levels showed wide differences in the groups at 1, 3, or 6th day post-injection. Despite the variable steroid levels, three individuals receiving either r-mtFSH or r-mtLH showed a great increase in a maturation-inducing steroid, $17{\alpha},20{beta}$-dihydroxy-4-pregnen-3-one, at 3 and 6 days. Taken together, these results suggest that biological efficacies of the recombinant FSH and LH should be further studied in the Manchurian trout.

• 한국발생생물학회:학술대회논문집
• /
• 한국발생생물학회 2004년도 추계학술대회
• /
• pp.30-30
• /
• 2004

• 대한생식의학회:학술대회논문집
• /
• 대한불임학회 2003년도 제45차 추계학술대회
• /
• pp.149-150
• /
• 2003

• 한국양식학회지
• /
• 제9권3호
• /
• pp.279-285
• /
• 1996

넙치의 전 암컷 집단의 생산을 위한 연구의 일환으로 실제 양식 어민이 손쉽게 이용할 수 있는 성전환 처리방법을 개발하고자, 부화 후 30일째부터 90일까지 60일간 $17{\beta}-methyltestoste-rone$ (MT)과 $estradiol-17{\beta}\;(E_2)$을 $1\~100$ ppb로 매일 2시간 동안 침지하여 성전환을 유도하였다. 부화 후 200일째의 실험군의 성비는 대조군에서 수컷이 $46.7\%$로 나타나 암수비가 거의 1 : 1이었으나, MT에 의한 수컷 유도율은 1 ppb 처리군이 $72.5\%$, 그리고 10 ppb 처리군이 $87.2\%$로 나타났고, 특히 100 ppb 처리군의 경우 $100\%$로 나타났다. $E_2$에 의한 암컷 유도율은 1 ppb 처리군에서 $75.5\%$ ,10 ppb 처리군에서 $91.9\%$였고, 가장 높은 농도인 100 ppb에서는 $97.2\%$로 나타났다. 호르몬 농도에 따른 각 처리군별 생존율 및 성장은 유의한 차이가 없었다(P>0.05).

• 한국수산과학회지
• /
• 제40권3호
• /
• pp.153-159
• /
• 2007

We studied oocyte steroidogenesis in relation to oocyte development in the greenling, Hexagrammos otakii, a marine multiple spawner. Vitellogenic and mature oocytes were incubated in vitro in the presence or absence of $[^3H]-17\;{\alpha}-hydroxyprogesterone$ as a precursor. The major metabolites were androgens [androstenedione $(A)_4)$ and testosterone (T)] and estrogens [$17\;{\beta}-estradiol\;(E_2)$ and estrone ($E_1$)] in vitellogenic oocytes. The metabolic rate of T was lower in 1.08 to 12-mm oocytes, while that of $E_2$ increased with oocyte size. The endogenous productions of T, $E_2$ and 17 ${\alpha}-hydroxy$, 20 ${\beta}-dihydroprogesterone\;(17{\alpha}20{\beta}OHP)$ were quantified using a radioimmunoassay in the non-precursor group. The endogenous levels of T and $E_2$ were highest in 1.08 to 12-mm oocytes and $17{\alpha}20{\beta}OHP$ was produced only in 1.90 to 95-mm oocytes. The relationship between oocyte size and steroidogenesis showed that 1.08 to 12-mm oocytes are full vitellogenic following induction of the maturation process. Moreover, $17{\alpha}20{\beta}OHP$ acts as a maturation inducing hormone in H. otakii.

• 한국수정란이식학회지
• /
• 제3권1호
• /
• pp.13-23
• /
• 1988

These studies were undertaken to examine the interaction of tamoxifen with sex steroid hormones in rat uterine activity. The uterine wet weights of the immature Tat uterus were examined after the administration of estradiol-l7$\beta$(1$\mu$g), tamoxifen(50$\mu$g), progesterone(lmg). The uterotropic activity in immature ovariectomized rats was observed under various treatment conditions following pretreatment with above drugs. The results obtained were as follows:1) Tamoxifen produced significant increase (p <0.01) in uterine wet weight compared with control group, although the increase was not as great as that seen with estradiol-17$\beta$. Administration of estradiol-17$\beta$ together with tamoxifen inhibited significantly the increase of uterine wet weight by estradiol-17$\beta$ (p < 0.01). Coadministration of progresterone with tamoxifen partly blocked the increase of tamoxifen-induced uterine wet weights by progesterone. 2) Estradiol-17$\beta$after the estradiol-17$\beta$ pretreatment discontinued the declining uterine wet weights due to the absence of estrogen support, but uteri continued to increase in weight if daily estradiol-17 $\beta$ was maintained. Administration of tamoxifen on the fourth day of estradiol-17$\beta$ treatment reduced uterine wet weights within 24 hours, and the weights continued to decline with additional tamoxifen. 3) The modest growth of the uterus induced by three daily injections of 5Opg tamoxifen remained stable for five days, with or without additional tamoxifen treatment. Coadministration of tamoxifen with estradiol17$\beta$ increased slightly the increase of uterine wet weight by tamoxifen. Coadministration of tamoxifen with progesterone inhibited the increase of uterine wet weight by tamoxifen. 4) The modest growth of the uterus induced by three daily injections of lmg progesterone reduced uterine wet weight to the control level for five days. Commencement of tamoxifen or estadiol-17 $\beta$ injections on the fourth day of progesterone treatment rapidly elevated uterine wet weight.

• 수산해양교육연구
• /
• 제24권6호
• /
• pp.1003-1012
• /
• 2012

The gonadosomatic index (GSI), sex steroid hormones and gonadal development of roughscale sole Clidoderma asperrimum cultured in indoor tank were investigated to evaluate its sexual maturation and reproductive cycle. The highest GSI values of female and male were $6.91{\pm}4.03$ (May) and $0.16{\pm}0.08$ (August), respectively. The reproductive cycle would be classified into four successive developmental stages: growing stage (December to February), maturation stage (March to April), ripe and spawning stage (May to June), recovery and resting stage (July to November). The highest plasma testosterone (T) and estradiol-$17{\beta}$ ($E_2$) levels of female were $259.4{\pm}76.8$ and $633.3{\pm}182.5$ pg/mL, respectively in May. Also $17{\alpha}$, $20{\beta}$-dihydroxy-4-pregen-3-one ($17{\alpha}$, $20{\beta}$-OHP) levels of female peaked in April before spawning season ($244.2{\pm}42.5$ pg/mL). The highest plasma testosterone (T) and 11-ketotestosterone levels of male were $231.0{\pm}46.0$ and $273.9{\pm}54.5$ pg/mL, respectively in April. But there was no significant difference in $17{\alpha}$, $20{\beta}$-OHP.