• 한국발생생물학회지:발생과생식
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• 제24권4호
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• pp.287-296
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• 2020

The absence of functional estrogen receptor α (Esr1) results in an overgrowth of the epididymal fat, as observed in estrogen receptor α knockout (ERαKO) mouse. The present research was aimed to evaluate expression of various molecules associated with adipocyte differentiation and maturation in the epididymal fat of ERαKO mouse at several postnatal ages by using quantitative real-time polymerase chain reaction. The highest transcript levels of all molecules were detected at 12 months of postnatal age, except leptin which the mRNA level was increased at 5 months of age and was unchanged until 12 months of age. The expression levels of CCAAT enhancer binding protein (Cebp) alpha, androgen receptor, and lipoprotein lipase were decreased at 5 months of age but increased at about 8 months of age. The mRNA levels of Cebp gamma and sterol regulatory element binding transcription factor 1 remained steady until 8 months of age. Continuous increases of transcript levels during postnatal period were found in Cebp beta, estrogen receptor (ER) beta, fatty acid binding protein 4, and delta like non-canonical Notch ligand 1. The increases of peroxisome proliferator-activated receptor gamma and adiponectin mRNA levels were detected as early as 8 months of age. The levels of fatty acid synthase and resistin transcript at 5 and 8 months of age were lower than that at 2 months of age. These findings show the aberrant expression patterns of genes related to adipocyte differentiation and maturation in the postnatal epididymal fat pad by the disruption of ER alpha function.

• Applied Microscopy
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• 제24권4호
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• pp.32-40
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• 1994

This study was undertaken to study the morphological changes of rat synapses during early postnatal periods. Neonatal rats were grouped by 1st, 2nd, 3rd, 4th and 6th postnatal weeks, and we observed the ultrastructural pattern of the synapses in the external plexiform layer of olfactory bulbs by electron microscopy. The results were as follows; 1. The numbers of synapses, lengths of synaptic thickenings and amounts of synaptic vesicles were markedly increased in the external plexiform layer during four postnatal weeks. 2. There was a tendency of increasing the proportion of the asymmetric synapse and the curved synapses during maturation. From the above results, it is suggested that the size of synapse is increasing during maturation, and at the same time the asymmetric synapses are formed from the symmetric type and the curved synapses are from the plane type.

• 한국발생생물학회지:발생과생식
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• 제22권4호
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• pp.351-360
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• 2018

The adipogenesis is a maturation process of pre-adipocyte cell into mature lipid-filled adipocyte cell. The adipogenesis begins at the late prenatal stage and continues until the early postnatal age. Because the adipogenesis and formation of adipose tissue persist during postnatal period and are precisely regulated by the action of numerous gene products, the present research was attempted to determine the expressional patterns of adipose tissue-associated genes in the rat epididymal fat pad at different postnatal ages, from 7 days to 2 years of ages, using a quantitative real-time PCR analysis. The basal expression levels of CCAAT/enhancer binding protein gamma, sterol regulatory element binding transcription factor 1, fatty acid binding protein 4, adiponectin, leptin, and resistin at the early postnatal ages were significantly lower than those at the elderly ages, even though a fluctuation of expressional levels was observed at some ages. The lowest expressional level of delta like non-canonical Notch ligand 1 was detected at 44 days and 5 months of ages. The expression of peroxisome proliferator-activated receptor gamma ($PPAR{\gamma}$) was the highest at 44 days of age, followed by a diminished expression of $PPAR{\gamma}$ at the elderly ages. These results indicate the existence of a complex regulatory mechanism(s) for expression of adipose tissueassociated genes in the rat epididymal fat during postnatal period.

• BMB Reports
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• 제34권6호
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• pp.573-577
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• 2001

The mammalian heart is known to undergo significant mechanical changes during fetal and neonatal development. The objective of this study was to define the ontogeny of the ryanodine receptor/$Ca^{2+}$ release channel and SERCA that play the major roles in excitation-contraction coupling. Whole ventricular homogenates of fetal (F) (19 and 22 days in gestation), postnatal (N) (1 and 7 days postnatal), and adult (A) (5 weeks postnatal) Sprague-Dawley rat hearts were used to study [$^3H$]ryanodine binding and oxalate-supported $^{45}Ca^{2+}$ uptake. For the ryanodine receptor, the major findings were: (1) The ryanodine receptor density, as determined by maximal [$^3H$]ryanodine binding ($B_{max}$), increased 3 fold between the F22 and A periods ($0.26{\pm}0.1$ vs. $0.73{\pm}0.07$ pmoles/mg protein, p<0.01), whereas there was no significant change during the F22 and N1 development phases ($0.26{\pm}0.1$ vs. $0.34{\pm}0.01$). (2) Affinity of the ryanodine receptor to ryanodine did not significantly change, as suggested by the lack of change in the $K_d$ during the development and maturation. For SERCA, changes started early with an increased rate of $Ca^{2+}$ uptake in the fetal periods (F19: $8.1{\pm}1.1$ vs. F22: $19.3{\pm}2.2$ nmoles/g protein/min; p<0.05) and peaked by 7 days (N7) of the postnatal age ($34.9{\pm}2.1$). Thus, we conclude that the quantitative changes occur in the ryanodine receptor during myocardial development. Also, the maturation of the $Ca^{2+}$ uptake appears to start earlier than that of the $Ca^{2+}$ release.

• International Journal of Oral Biology
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• 제43권4호
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• pp.177-183
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• 2018

The objective of this study was to examine the expression pattern of Kelch-like ECH-associated protein 1 (Keap1) in the maxillary $2^{nd}$ molar germs of rats. We used the maxillary $2^{nd}$ molar germs in rats' pup at postnatal day 3 (bell stage), 6 (crown formation stage) and 9 (root formation stage). The investigation on mRNA and protein levels were done using reverse transcription - polymerase chain reaction and western blot. Localization of Keap 1 in the maxillary $2^{nd}$ molar germs were revealed through immunofluorescence staining. Keap1 from the maxillary 2nd molar germs were mostly manifested on postnatal day 3 and dramatically decreased on postnatal day 6 and 9 at mRNA and protein levels, while amelogenin and ameloblastin increased during the development of maxillary 2nd molar germs. During immunofluorescence analysis, the strong immunoreactivity against Keap1 was detected in the apical side of ameloblasts at the presecretory and secretory stages. However, Keap1 expression was hardly observed in the ameloblasts at the maturation stage. These results shows that Keap1 is strongly expressed in the presecretory and secretory ameloblasts of amelogenesis, and suggest that Keap1 may be a crucial molecule for the regulatory mechanisms tasked with the formation of enamel layer.

• Molecules and Cells
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• 제46권11호
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• pp.672-674
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• 2023

Schematic diagram of the interaction between the intestinal muscularis externa (MMΦ) macrophages and the enteric nervous system (ENS) neurons during different developmental periods. At the early postnatal stage, MMΦs play a critical role in ENS maturation and refinement through synaptic pruning and enteric neuron phagocytosis. In addition, during the adult stage, a specific MMΦ subset named neuron-associated (NA)-MMΦ, supports enteric neuronal survival and functions. Conversely, enteric neurons promote the phenotypic MMΦ changes by secreting transforming growth factor-β (TGFβ), transitioning them from a phagocytic phenotype in the early postnatal period to a neuroprotective and immune-surveillant phenotype in the young adult period. Disruptions in these interactions could lead to alterations in the enteric neuron numbers, ultimately resulting in reduced gut motility.

• 생명과학회지
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• 제17권10호
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• pp.1347-1353
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• 2007

성장과정 중 흰쥐 신장에서 나타나는 복합당질의 변화를 알아보기 위해 18일 태자부터 성체에 이르는 신장을 형태적 관찰과 더불어 9가지 lectin (SBA, DBA, PNA, BSL-1, RCA-1, sWGA, UEA-1, LCA 및 Con A)으로 검색하였다. 신장 발생단계에서 성숙한 신원구조와 함께 미성숙한 구조물 즉 소포와 요관아 등이 생후 14일에 이르기까지 관찰되었으며 생후 21일에 이르러 성체와 유사한 구조적 특성을 보였다. 복합당질의 변화를 보면 사구체에서 RCA-1, LCA및 Con A에 반응을 나타내며 RCA-1 및 LCA는 태자와 신생쥐에서 일시적으로 증가하다 성체에서 관찰되지 않으나 Con A는 성장과 더불어 증가하였다. 근위곡요세관은 UEA-1을 제외한 모든 lectin에 반응하며 DBA, SBA, PNA, BSL-1, RCA-1 및 Con A반응이 성장과 더불어 증가하며 특히 RCA-1과 BSL-1반응이 현저하였다. 이에 비해 sWGA와 LCA반응은 성장과정에 일시적으로 증가하며 성체에 이를수록 감소하였다. 원위곡요세관도 근위곡요세관 유사하게 DBA, SBA, PNA, BSL-1 및 RCA-1반응은 성숙과 함께 증가하나 LCA반응은 성숙과정에 일시적으로 증가하며 성체에서 감소하였다. 집합관에서는 DBA, SBA, PNA, sWGA반응이 성숙과 동시에 증가하나 BSL-1, RCA-1, LCA반응은 미성숙관에서 일시적으로 증가하였다. 이상의 반응으로 보아 신장발생과정에서 형태적 기능적 성숙과 함께 다양한 복합당질의 변화를 보이는데 대체로 성숙에 따라 반응이 증가하는 복합당질군과 미성숙기에 일시적으로 증가하며 성체에서 감소하는 복합당질군으로 대별할 수 있었다. 이러한 출생전후 복합당질의 변화는 신장의 기능적 성숙과정과 연관성을 가지며 발생과정에서 현저한 변화를 나타내는 복합당질은 정상 신장발생에 대한 표지인자로 유용할 것이다.

• 한국의학물리학회지:의학물리
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• 제16권4호
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• pp.214-219
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• 2005

한국형 인공시각장치 개발 목적으로 토끼망막을 사용하여 차후 개발될 인공시각장치에 인가하기 위한 적절한 전기자극 파라미터를 추출하는 실험을 수행하였다. 유전적 망막변성모델인 RD mouse (rd/rd (C3H/HeJ))를 망막질환모델로 사용하기 앞서 본 연구에서는 SD rat을 사용하여 설치류의 생후성숙기간 동안 변화하는 망막신경절세포의 빛 자극에 대한 변화 양상을 전반적으로 파악하는 control 실험을 하였다. 망막신경절세포의 흥분파는 8${\times}$8의 MEA (multi- electrode array)로 기록하였다. 개안 이전시기(pre-eye opening period)인 생후 15일까지는 망막신경절세포의 자발적 집단발사현상 (moving spontaneous bursts)이 옮겨 다니는 것을 발견하였다. 이 시기의 쥐들은 시각기능이 완성되지 않아 빛 자극에 의해 유발되는 흥분파를 보이지 않으며 오로지 이들의 촉각(tactile sense)에 의하여서만 이동하는 것을 관찰하였다. 그러나 생후 2주(post-eye opening period)가 지나면, 빛 자극에 의해 ON, OFF, ON/OFF 반응이 유발됨을 확인할 수 있었다. 전체적인 ON, OFF, 그리고 ON/OFF 망막신경절세포의 양상은 각각 $40\%,\;50\%,\;5\%$였으며, 이들 세포가 확인된 안구에서의 해부학적인 위치는 등쪽 관자방향(dorso-temporal)이 $50\%$, 배쪽 방향(ventral)이 $37.5\%$, 그리고 등쪽 코 방향(dorso-nasal)이 $12.5\%$로 나타났다. 설치류 망막을 대상으로 빛 자극에 의한 반응을 알아보는 실험을 할 때 생후 2${\~}$3주령이 가장 적합한 시기임을 확인하였다. 것이 바람직하다고 판단되었다.의한 발아촉진 효과는 종피의 탈색과 부식으로 인한 광흡수의 증대에서 기인되는 것으로 추측된다.3월 8일과 3월 15일 피복처리구의 그린업이 가장 효과적이었다. 한국잔디 및 한지형 잔디의 비닐 피복으로 인한 초봄 그린업 촉진시 유의할 점은 충분한 수분 유지를 위해 비닐 피복전에 관수를 하거나 비온 후에 비닐 피복하는 것이 좋으며, 비닐 제거시 잔디의 일소현상의 피해를 줄이기 위해 흐린날 비닐을 제거하는 것이 좋을 것으로 판단되었다.유발식이 급여로 $524\%$가 증가된 동맥경화지수는 질경이 에틸아세테이트 분획 병합투여로 대조군에 비하여 $40.2\%,\;51.2\%$가 감소됨으로써 동맥경화 발병 위험율이 대조군에 비하여 감소되었다. HDL-콜레스테롤 함량/총콜레스테롤 함량 비는 고콜레스테롤혈증 유발 식이 급여로 정상군보다 $73.9\%$가 감소됐으나 질경이 에틸아세테이트 분획 병합투여로 대조군에 비하여 유의한 증가를 나타냈다. 26두가 발정 반응($96.3\%$)을 나타내어 2.75${\~}$3.5의 경우가 2.50 이하의 경우에 비하여 높은 발정반응을 나타내었다.osterone과 0.40의 정의 상관이었고 근내지방도와 creatinine 농도간에는 -0.55의 비교적 높은 음의 상관계수가 추정되었으나 유의성은 인정되지 않았다. 6. 한우 비거세우의 도살시 혈청 성분 농도와 도체형질과의 상관에서 육량지수는 연령에 대해 보정한 HDLC 농도와 -0.71의 음의 상관이었으며, 도체율은 globulin과 0.70의 높은 정의 상관이었고, 등지방두께는 연령으로 보정된 HDLC와 0.69로 정의 상관관계를 보였다. 도체중은 triglyceride와 0.51의 정의 상관, 배최장근단면적은 testosterone과 -0.91,

• Journal of Animal Science and Technology
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• 제55권4호
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• pp.249-255
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• 2013

Intercellular interactions are important for the proper development and regulation of tissue function. This is especially necessary in the epididymis, a part of male reproductive tract where sperm become mature and acquire their fertilizing capacity. The caput region of the epididymis consists of several types of cells, including principal, basal, and apical cells. Direct intercellular communication is thus required to precisely regulate the functions of the caput epididymis. In this regard, connexin (Cx) is a molecule that forms channels, which allow the direct exchange of small molecules between cells, enabling intercellular communication. In this study, the expression of Cx isoforms in the caput epididymis at different postnatal ages was determined by using quantitative real-time polymerase chain reaction analysis. Nine of 13 Cx isoforms were detected. The transcript levels of Cx30.3, 31, 31.1, 32, and 40 were highest at 45 days of age, while the expression of Cx43 and 45 gradually decreased with age. A substantial fluctuation of Cx26 expression was detected, with significant decreases before and during puberty, followed by a transient increase at adult-hood and rapid decreases at an old age. A significant increase in Cx37 transcript was observed at 25 days of age, followed by gradual decreases at adult and old ages. These results indicate the significant differential expression of various Cx isoforms in the caput epididymis during postnatal development. It further suggests that the functional regulation and developmental maturation of the caput epididymis are highly related to the postnatal age-related differential expression of Cx isoforms.

• 한국발생생물학회지:발생과생식
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• 제23권3호
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• pp.213-221
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• 2019

The epididymal fat of mouse is a part of visceral fat deposit and is divided into the distal or proximal part based on its histochemical characteristics. Even though the formation of the epididymal fat pad begins before the birth, a detailed adipogenic procedure of the epididymal fat has not been revealed. The epididymal fat pad becomes enlarged and expended with age, and expressional changes of numerous genes are associated with the maturation of fat tissues. In the present research, expressional patterns of adipose tissue-related genes in the distal epididymal fat of mouse at 2, 5, 8, and 12 months of postnatal age were determined by a quantitative real-time polymerase chain reaction (PCR) analysis. The lowest transcript levels of fatty acid binding protein 4 (Fabp4), lipoprotein lipase (Lpl), delta like non-canonical Notch ligand 1 (Dlk1), peroxisome proliferator-activated receptor gamma (Pparg), leptin (Lep), adiponectin (Adipoq), and resistin (Retn) were detected at 2 months of age, except fatty acid synthase (Fasn) showing the lowest level at 5 months of age. Even though expression of Lep and Fabp4 were gradually increased until 12 months of age, significant increases of Pparg and Adipoq transcript levels were continued until 8 months of age. The transcript levels of Lpl, Rent, Dlk1, and Fasn were significantly increased at 8 months of age, compared with those at 2 months of age. The current findings suggest that the expansion of the distal epididymal fat of mouse during postnatal period would be companied with differential expression of various adipocyte-associated molecules.