• 한국환경성돌연변이발암원학회:학술대회논문집
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• 한국환경성돌연변이발암원학회 2003년도 추계학술대회
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• pp.149-149
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• 2003

• Applied Microscopy
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• 제27권2호
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• pp.131-144
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• 1997

The present study was carried out to investigate the processes of the ultrastructural differentiation and the acetylcholinesterase (AChE) activities of the developing rat retina. The results are as follows. The retina of fetal rat on the 13th day of gestation showed the early stage of differentiation. Briefly, there appeared dividing chromosomes, the plentiful free ribosomes, and the high ratio of nucleus to cytoplasm. The reaction products by AChE were localized at the membrane of endoplasmic reticulum and on the outer membrane of nucleus. Ultrastructures and AChE activities in the retina of the fetal rats on the 18th day of gestation were similar to those of the prior stages, except the appearence of rough endoplasmic reticulum and Golgi apparatus. According to the ultrastructural observations, the rat retina was still in immature state at birth, but the pigment epithelial cells were fully differentiated, e. g. the increase of melanin granules, the development of mitochondria and Golgi apparatus. The AChE activity was weekly detected. The differentiated retinal layers and the outer segment of photoreceptor cells were observed on the 7th postnatal day. And the pigment epithelium appeared to be fully differentiated. On the 14th postnatal day, rat retina were completely differentiated. In other words, the rat retina was characterized by the prominent outer segments, phagocytosed residues in the pigment epithelium, and the localization of reaction products by AChE in the synapses. In conclusion, the differentiation of rat retina is charaterized by the changes of cell shape, the increase of retinal layers, and the alterations of AChE activities. It seems that rat retina is to be functional from 2 weeks of birth onward, coinciding with the eye opening of the juvenile rats.

• 대한수의학회지
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• 제38권3호
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• pp.455-460
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• 1998

This study was designed to investigate the distributions of the positive cells in rat spleens by two monoclonal antibodies of MT1 and MB2. The spleens of immature 10 rats (Sprague Duwely, approximately 200gm) were collected and paraffin-embedded sections of spleens were stained with immunohistochemical methods. Higher proportions of MT1-positive cell number in spleens were ordered as marginal zone(8.5~18.1%), red pulp(2.1~8.8%) and periarterial lymphoid sheath(0~1.6%) in white pulp, and those of MB2-positive cell number are ordered as the central area of the periarterial lymphoid sheath(100%), red pulp(29.1~45.0%), marginal zone(15.2~30.4%), and peripheral area of periarterial lymphoid sheath(2.3~3.5%). The positive cells by MB2 are more numerous in number than by MT1. The above results were concluded that the positive cells by above two monoclonal antibodies were scattered throughout the red pulp and marginal zone, but in the central area of the periarterial lymphoid sheath, the MB2-positive cells only were present.

• 한국식품조리과학회지
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• 제21권6호통권90호
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• pp.769-775
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• 2005

미성숙 흰쥐에서 누에 번데기 수용성과 지용성 추출 물 및 한약재가 첨가된 누에 번데기 수용성 추출물을 투여하여 에스트로젠 증식 관련 인자의 발현을 확인한 결과는 다음과 같다. 미성숙 흰쥐에서 누에 번데기 수용성 추출물(KW), 누에 번데기 지용성 추출물(KO) 및 KW에 하수오, 인삼, 울금을 7:1:1:1의 비율로 첨가한 복합체(MK)를 각각 100 mg/kg와 500 mg/kg의 농도로 30일간 경구투여한 결과 체중은 유의적인 변화를 나타내지 않았다. 체중에 대한 자궁의 무게는 정상 대조군에 대하여 실험군에서 KW500을 제외하고는 모두 유의적인 증가를 나타내었으며 K0500, KW100, MK100 순으로 각각 $0.49\%,\;0.48\%,\;0.44\%$의 높은 값을 나타내었다. 체중에 대한 난소의 무게는 정상 대조군에 대해 MK군을 제외하고 모두 유의적인 변화를 보였으며 KW100군이 가장 높은 값을 나타내었다. 미성숙 흰쥐의 혈청 내 AST와 ALT 활성 및 creatinine 농도는 모두 군 간에 유의적인 변화는 보이지 않았다. 즉 모든시료가 간과 신장에 독성을 나타내지 않은 결과이다. $ER\alpha$와 $ER\beta$의 발현을 densitometer로 수치화하여 정상대조군을 기준으로 발현의 증가와 억제를 백분율로 표시한 결과 KW100(100 mg/kg)와 MK500(500 mg/kg) 군이 $ER\alpha$의 발현을 유의적으로 증가시켰으며 KW100(100 mg/kg), KW500(500 mg/kg), 및 MK100(100 mg/kg)군이 $ER\beta$의 발현을 유의적으로 증가시켰다. 따라서 누에 번데기 수용성 추출물 및 한약재(인삼, 하수오, 울금)를 첨가한 누에 번데기 수용성 추출물이 생체에서 높은 에스트로젠 활성을 가지고 있는 것으로 사료된다.

• Toxicological Research
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• 제16권3호
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• pp.201-209
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• 2000

In association with the international validation program to establish a rodent uterotrophic assay, we conducted preliminary uterotrophic assay proposed by GECD using immature female rats. In the present study, oral and subcutaneous routes were chosen to compare the effects of estrogenic com-pounds in the two dosing regimens. The reference compound ethinyl estradiol (EE) and the antagonist ZM189154(ZM) were administered by gavage or subcutaneously (s.c.) to immature female SD rats from 20 to 22 days of age. For each study, sixty-six female rats were randomly assigned to eleven groups: Untreated control, EE 0,0.01, 0.03, 0.1, 0.3, 1.0,3.0 and 10.0 $\mu\textrm{g}$/kg, EE 3.0 $\mu\textrm{g}$/kg(gavage)/0.3 $\mu\textrm{g}$/kg(s.c) & ZM 0.1 mg/kg, and EE 3.0 $\mu\textrm{g}$/kg(gavage)/0.3 $\mu\textrm{g}$/kg (s.c) & ZM 1.0 mg/kg. There were no treatment-related changes in clinical signs, body weights, food consumption, and necropsy findings in any groups of two studies. The wet and blotted uterus weights increased dose-dependently. Histopathological examination revealed that diameter of uterine duct, height of uterine luminal epithelium. and height oj vaginal epithelium increased dose-dependently. The proliferating cell nuclear antigen (PCNA) immunoreactive cells were increased in number dose-dependently. The estrogenic effects observed in the present studies occurred at $\geq$ 0.3 $\mu\textrm{g}$/kg of oral dose and $\geq$ 0.1 $\mu\textrm{g}$/kg of s.c. dose. An antagonistic effect of ZM against EE was found in both uterus weight and histopathological parameters. From the results obtained, it can be concluded that dose-dependence of the uterotrophic assay using EE and ZM was well demonstrated by gavage and subcutaneous administration and that the estrogenic effects of EE by s.c. dose were higher than those by gavage administration. In addition, blotted uterus weight was more sensitive than wet uterus weight and vaginal epithelial height was found to be the most sensitive parameter among the parameters examined.

• 대한수의학회지
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• 제39권2호
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• pp.276-286
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• 1999

In the present study, to understand how gonadotropin-releasing hormone (GnRH) affects ovarian functions in superovulated rats, we examined the effects of GnRH agonist on the ovulatory response, the morphological normality and nuclear maturation of ovulated oocytes, the ovarian weight, the ovarian histology, and the circulating steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in immature rats pretreated with 30IU pregnant mare serum gonadotropin (PMSG) and supplemented with 10IU human chorionic gonadotropin(hCG). GnRH agonist was intravenously injected via jugular vein catheter every 20min for 4hrs in early follicular phase (from 6hr after PMSG) of superovulated rats. In addition, GnRH antagonist, Antide, was intravenously injected in combination with GnRH agonist to verify the effects of GnRH agonist on ovarian functions. All animals were sacrificed at 72hr after PMSG administration. The administration with GnRH agonist in early follicular phase of superovulated rats caused inhibition of ovulatory response, increased the proportion of abnormal appearing oocytes(especially, in the rats of the group treated with 500ng GnRH agonist), decreased ovarian weight and promote follicular atresia, compared to those from the rats of control regimen that were not treated with GnRH agonist. In addition, the treatment with GnRH agonist in the superovulated rat distinctly decreased serum steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in preovulatory phase. On the other hand, the inhibitory effects of GnRH agonist treatment in superovulation-pretreated rats on ovarian functions were totally reversed by the combination with GnRH antagonist, Antide. The nuclear maturation of oocytes recovered from the oviducts in immature rats treated with GnRH agonist and/or GnRH antagonist was characterized by prematurity and asynchronization in early follicular phase, which was similar to control group. The overall results of this study indicate that GnRH agonist disturbs directly ovarian function in early follicular phase of superovulated immature rats in terms of ovulatory response and morphological normality of ovulated oocytes. This concept has been further evidenced by the findings of a great decrease in ovarian weight, a marked increase in follicular and a distinct decrease circulating steroid hormone ($17{\beta}$-estradiol, progesterone and testosterone) levels in GnRH agonist treatment regimen in early follicular phase.

• Journal of Animal Science and Technology
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• 제59권5호
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• pp.9.1-9.1
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• 2017

• 대한방사선기술학회지:방사선기술과학
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• 제41권5호
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• pp.471-478
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• 2018

Oogenesis process of ovary produces a lot of undifferentiated cells. Especially, the radiation exposure of early immature cells in the process of growth to oocyte causes serious disabilities. This study examined the radiation damage mechanism of undifferentiated cells and organelles in oogenesis process, and the radioprotection after injection of alliin. The ultrastructure after 7Gy X-ray irradiation on the white rat was observed in the experiment. The results is as follows. It was observed that the nucleus membrane of an oogonium was damaged and vacuolated in the several parts after 15 days of irradiation. The damage of mitochondria membrane and flow in cytoplasm after 20 and 30 days was found in the oogonium. After 40 days observation, peroxidation of fat droplets was found and organelles were tangled each other in ovary tissue. The partial damage of nuclear membrane in oogonium past 15 days after injection of alliin was found, but decreased remarkably. Mitochondria, Golgi body, and rough endoplasmic reticulum were also clearly observed, therefore, radioprotection effects in alliin was confirmed partially.

• 한국동물학회지
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• 제37권1호
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• pp.130-136
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• 1994

Although alteration in protein phosphorylation by specific protein kinases is of importance in transducing cellular signals in a variety of neural/endocrine systems, little is known about protein phosphorylation in the hvpothalamus. The present study aims to explore whether activation of the second messenger-dependent protein kinases affects phosphorylation of specific proteins using a cell free phosphorylation system followed by SDS-polvacrylamide gel electrophoresis. Cytoplasmic fractions derived from hvpothalami of immature rats were used as substrates and several activators and/or inhibitors of CAMP-, phosphatidylinositol- and Ca2+-calmodulin-dependent protein kinases were assessed. Many endogenous proteins were extensively phosphorylated and depending on the signal transduction pathways, phosphorvlation profiles were markedly different. The present data indicate that extracellular signals may affect cellular events through protein phosphorylation by second messengers-protein kinases in the rat hypothalamus.

• Applied Microscopy
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• 제16권2호
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• pp.75-91
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• 1986

Differentiation of the rat testis was studied by light and electron microscope from the fetal stage up to the newborn or adult stage. The purpose of the present study is to investigate the ultrastructural changes of seminiferous tubules and interstitial tissue during the developmental process. The results were as follows: the seminiferous tubule diameter began to increase from birth and was fully developed at 30 to 40 days of age through intratubular cell proliferations. Basement membrane and myoid cells lining the seminiferous tubules were differentiated at 17 days gestation. At the fetal stage, seminiferous tubules were primarily composed of Sertoli cells and the differentiation of Sertoli and germ cells progressed from the newborn stage. Spermatids and immature spermatozoa are appeared at 40 days of age, so from this time, spermatogenesis occurred actively until the adult stage. Sertoli cells aided germ cell differentiation and phagocytosed the parts of the spermatid cytoplasm. Leydig ce]] development follows a biphasic pattern: a fetal phase and then an adult phase from 20 days of age. In conclusion, the rat testis is already developed to some extent by the fetal stage and is functional after 50 days of age. Therefore, these findings indicate that differentiation of Sertoli and Leydig cells precedes the onset of spermatogenesis.