BACKGROUND & AIMS: :Association learning during suckling was investigated. Five-day-old rats equipped with tongue cannulae placed either 2 mm rostral or 4-6 mm caudal to the intermolar eminence received sweet or salty solutions while suckling. This ingestion was followed by lithium chloride toxicosis. Pups with anterior cannulae took in considerably less fluid than control pups when tested 5 or 16 days later. A series of control groups demonstrated that this acquired aversion was associative in nature. Pups with posterior cannulae did not form the association. The failure of 5-day-old rats with posterior cannulae to form associations while suckling is not due to the prevention of conditioning by the act of suckling per se. Rather, the failure rests in the fluid's not reaching anterior taste receptors when injected into the posterior oropharynx, where the nipple normally empties its contents. These findings are discussed in terms of the transfer of information obtained during suckling prior to weaning, to feeding and drinking during and after weaning.

背景与目标： : 研究了哺乳过程中的关联学习。五天大的老鼠在哺乳时，将舌管置于2毫米的鼻孔或4 6毫米的尾部，以获得甜或咸的溶液。摄入后发生氯化锂中毒。在5或16天后进行测试时，带有前套管的幼崽吸收的液体比对照幼崽少得多。一系列对照组表明，这种获得性厌恶本质上是关联的。带有后套管的幼崽没有形成关联。5天大的大鼠在哺乳过程中无法形成关联，这并不是由于哺乳行为本身对调理的预防。相反，失败在于将液体注射到后口咽部时未到达前味觉感受器，乳头通常会排空其内容物。这些发现是根据断奶前哺乳过程中获得的信息的转移，断奶期间和断奶后的喂养和饮酒来讨论的。

BACKGROUND & AIMS: :Effects of the suckling stimulus on the daily LH surge induced by chronic oestrogen treatment were examined in ovariectomized lactating rats. Wistar-Imamichi strain rats were kept under 14 h light:10 h darkness (lights on at 05.00 h). Litter size was adjusted to eight on day 1 (day 0 = day of parturition) and ovariectomy performed on day 2. Lactating rats deprived of their litters on day 0 served as nonlactating controls. Silicone elastomer tubing filled with oestradiol was implanted on day 6 or 15. Blood samples were collected through an indwelling cannula at 10.00 and 17.00 h on each day after implantation to detect daily LH surges. Daily LH surges occurred in the late afternoon in both lactating and non-lactating rats implanted with oestradiol on day 6 or 15. The amplitude of daily LH surges in lactating rats implanted on day 6 declined much more rapidly than in non-lactating rats implanted on day 6, but no significant difference was found in the profile of the LH surge between lactating and non-lactating rats implanted on day 15. Pituitary LH contents just before the daily LH surge (12.00-12.30 h) 4 days after implantation in lactating rats implanted with oestradiol on day 6 were significantly less than those in nonlactating rats implanted with oestradiol on day 6 or 15 and in lactating rats implanted on day 15.(ABSTRACT TRUNCATED AT 250 WORDS)

背景与目标： : 在去卵巢的泌乳大鼠中检查了哺乳刺激对慢性雌激素治疗引起的每日LH激增的影响。将Wistar-Imamichi品系大鼠保持在14小时的光照下: 10小时的黑暗 (在05.00小时开灯)。在第1天 (第0天 = 分娩日) 将产仔数调整为8，在第2天进行卵巢切除术。在第0天被剥夺产仔的哺乳期大鼠作为非哺乳期对照组。在第6天或第15天植入填充雌二醇的有机硅弹性体管。在植入后每天10.00和17.00小时通过留置套管收集血液样本，以检测每日LH浪涌。在第6天或第15天植入雌二醇的哺乳期和非哺乳期大鼠，每天下午晚些时候都会出现LH激增。在第6天植入的哺乳期大鼠中，每日LH激增的幅度比在第6天植入的非哺乳期大鼠下降得更快，但在哺乳期和非哺乳期大鼠之间的LH激增的分布没有发现显着差异。在第15天植入的大鼠。在第6天植入雌二醇的哺乳期大鼠植入后4天的每日LH激增 (12.00-12.30 h) 之前的垂体LH含量显着低于在第6天或第15天植入雌二醇的非哺乳期大鼠和在第15天植入的哺乳期大鼠。(摘要截短于250字)

BACKGROUND & AIMS: BACKGROUND:Soon after birth, all mammals must initiate milk suckling to survive. In rodents, this innate behavior is critically dependent on uncharacterized maternally derived chemosensory ligands. Recently, the first pheromone sufficient to initiate suckling was isolated from the rabbit. Identification of the olfactory cues that trigger first suckling in the mouse would provide the means to determine the neural mechanisms that generate innate behavior. RESULTS:Here we use behavioral analysis, metabolomics, and calcium imaging of primary sensory neurons and find no evidence of ligands with intrinsic bioactivity, such as pheromones, acting to promote first suckling in the mouse. Instead, we find that the initiation of suckling is dependent on variable blends of maternal "signature odors" that are learned and recognized prior to first suckling. CONCLUSIONS:As observed with pheromone-mediated behavior, the response to signature odors releases innate behavior. However, this mechanism tolerates variability in both the signaling ligands and sensory neurons, which may maximize the probability that this first essential behavior is successfully initiated. These results suggest that mammalian species have evolved multiple strategies to ensure the onset of this critical behavior.

背景与目标：

BACKGROUND & AIMS: :Previous work from our laboratory has shown that there is a much higher level of bFGF and GFAP immunoreactivity in area 2 of the cingulate cortex (Cg2) of rats on day 16 of lactation than in cycling or late pregnant females. To examine the time course of this change, in the first of the current studies, we compared bFGF and GFAP immunoreactivity in the brains of lactating females on postpartum day 4 (PP4), day 10 (PP10), day 16 (PP16), and day 24 (PP24) with that of cycling and ovariectomized (OVX) females. In the second study, we investigated whether the maintenance of these changes in bFGF and GFAP depended on suckling stimulation by removing litters on day 1 or day 16 postpartum and examining the brains of the dams on day 4 (Pr4) or day 24 (Pr24) postpartum, respectively. bFGF and GFAP immunoreactivity within Cg2 and the medial preoptic area (MPOA) were measured. In both experiments astrocytic bFGF and GFAP surface density in the Cg2 varied significantly across groups. All postpartum rats, regardless of stage of lactation or presence of the litter, had significantly higher levels of bFGF and GFAP immunoreactivity than cycling animals. Thus, the maintenance of this upregulation in bFGF and GFAP immunoreactivity does not depend on suckling stimulation. Consistent with our previous report, astrocytic bFGF was also elevated in the MPOA of PP16 animals. These data suggest a robust, long-lasting, postpartum change in bFGF and GFAP immunoreactivity in Cg2 and a role for this area of the cortex in the physiological and behavioral adaptations that accompany reproductive experience.

背景与目标： : 我们实验室的先前工作表明，哺乳期第16天大鼠扣带回皮层 (Cg2) 区域2的bFGF和GFAP免疫反应性比骑自行车或怀孕后期的雌性高得多。为了检查这种变化的时间过程，在当前的第一项研究中，我们比较了产后第4天 (PP4)，第10天 (PP10)，第16天 (PP16) 哺乳期女性大脑中bFGF和GFAP的免疫反应性，第24天 (PP24) 与骑自行车和卵巢切除 (OVX) 的女性。在第二项研究中，我们调查了bFGF和GFAP这些变化的维持是否取决于哺乳刺激，方法是在产后第1天或第16天清除产仔，并在产后第4天 (Pr4) 或第24天 (Pr24) 检查大坝的大脑。测量了Cg2和内侧视前区 (MPOA) 内的bFGF和GFAP免疫反应性。在两个实验中，Cg2中的星形胶质bFGF和GFAP表面密度在各组之间均显着变化。所有产后大鼠，无论泌乳阶段或存在垫料，其bFGF和GFAP免疫反应性均明显高于骑自行车的动物。因此，bFGF和GFAP免疫反应性中这种上调的维持并不取决于哺乳刺激。与我们先前的报告一致，星形细胞bFGF在PP16动物的MPOA中也升高。这些数据表明，Cg2中bFGF和GFAP免疫反应性在产后发生了强大的，持久的变化，并且皮质的这一区域在伴随生殖经历的生理和行为适应中发挥了作用。

BACKGROUND & AIMS: :1. Early undernutrition can cause permanent functional changes in the central nervous system. Alterations in enzymes involved in neurotransmitter metabolism have been reported to result from early undernutrition. 2. In a previous study, we demonstrated that undernutrition during suckling decreases ATP and ADP hydrolysis by synaptosomes from cerebral cortex by about 20% of the value found in 20-day-old well-nourished rats (J. B. T. Rocha, C. F. Mello, J. J. F. Sarkis and R. D. Dias, British Journal of Nutrition, 63:273-283, 1990). In the present study, we investigated whether this deficit persists in synaptosomes from cerebral cortex of nutritionally rehabilitated adult rats. 3. Rats were undernourished from birth to 25 days of life by feeding their dams a 7% casein (w/w) diet, while well-nourished offspring were fed by mothers maintained on a 28% casein diet. 4. In contrast to the results previously obtained in young rats, the synaptosomes obtained from the cerebral cortex of early undernourished adult rats hydrolyzed ATP and ADP more efficiently than did those obtained from well-nourished rats. Specific activity (nmol min-1 mg protein-1, mean +/- SD) was 114.9 +/- 9.5 for undernourished rats (N = 8) vs 94.1 +/- 9.5 for well-nourished rats (N = 8) for ATP, and 50.4 +/- 6.1 (N = 8) vs 38.8 +/- 4.5 (N = 8) for ADP. These results suggest that the deficits found in young rats disappear in rehabilitated adult rats.

背景与目标： : 1。早期营养不良会导致中枢神经系统的永久性功能改变。据报道，与神经递质代谢有关的酶的改变是由于早期营养不良所致。2.在先前的研究中，我们证明了哺乳过程中的营养不足使大脑皮层突触小体的ATP和ADP水解降低了20日龄营养良好的大鼠的约20% (J. B. T. Rocha，C. F. Mello，J. F. Sarkis和R. D. Dias，英国营养杂志，63:273-283，1990)。在本研究中，我们调查了营养康复的成年大鼠大脑皮层突触体中这种缺陷是否持续存在。3.大鼠从出生到生命的25天，通过给它们的水坝喂食7% 的酪蛋白 (w/w) 饮食来营养不良，而营养良好的后代则由维持28% 酪蛋白饮食的母亲喂养。4.与先前在幼鼠中获得的结果相反，从营养不足的成年大鼠的大脑皮层获得的突触体比从营养良好的大鼠获得的突触体更有效地水解ATP和ADP。营养不足的大鼠 (N = 8) 的比活性 (nmol min-1 mg蛋白-1，平均/- SD) 为114.9/- 9.5，而营养良好的大鼠 (N = 8) 的比活性为94.1/- 9.5，ADP的50.4 +/- 6.1 (N = 8) vs 38.8 +/- 4.5 (N = 8)。这些结果表明，在康复的成年大鼠中，在幼鼠中发现的缺陷消失了。

BACKGROUND & AIMS: The objective of this study was to determine whether exposure of early suckling young of the opossum Monodelphis domestica to ultraviolet A (UVA) radiation (320-400 nm) can lead to the development of melanocytic lesions similar to those induced after exposure to ultraviolet B (UVB) radiation (280-320 nm) to total doses as low as 380 J/m2. A total of 576 sucklings received nine exposures of 0.6, 2.6 or 15.5 kJ/m2 per dose (total doses approximately 6, 23 and 140 kJ/m2, respectively) from a Blak Ray lamp source with a narrow range emission at 365 nm. A further 280 sucklings were exposed in the same way to doses of 2.6 kJ/m2 per dose (total approximately 23 kJ/m2) broad-band UVA with visible wavelengths from a Dermalight lamp. Frequency of litter loss following all of the UVA-exposure protocols was similar to that within the same stocks in the colony at large. Only one of the 856 UVA-exposed individuals possessed a melanocytic lesion at the 5 month assessment point. No radiation-induced lesions of any type were evident on the skin of the other animals exposed as sucklings. The affected male was from a group of 70 individuals exposed to the highest total dose (140 kJ/m2) from the Blak Ray light source. The melanocytic hyperplasia was provisionally identified as a potential melanoma but it slowly regressed as the animal aged. We conclude that in the opossum suckling exposure system, the potency of UVA for melanoma induction is extremely low compared with that of UVB. Possible explanations, amenable to further investigations, are given for the low UVA sensitivity of the suckling model compared to the adult exposure model of Ley (Ley, R. D. [1997] Cancer Res. 57, 3682-3684).

背景与目标： 这项研究的目的是确定是否暴露于紫外线A (UVA) 辐射 (320-400 nm) 的负鼠的早期乳鼠幼仔会导致黑素细胞病变的发展，类似于暴露于紫外线B (UVB) 辐射 (280-320 nm) 后引起的黑素细胞病变。总剂量低至380 J/m2。总共576只乳类从具有365纳米窄范围发射的Blak射线灯源中接受了每剂量0.6、2.6或15.5 kJ/m2的九次曝光 (总剂量分别约为6、23和140 kJ/m2)。以同样的方式将另外的280乳类暴露于每剂量2.6 kJ/m2的剂量 (总计约23 kj/m2) 具有来自dermallight灯的可见波长的宽带UVA。遵循所有UVA暴露方案的凋落物流失频率与整个殖民地中相同种群中的凋落物流失频率相似。856个暴露于UVA的个体中只有一个在5个月的评估点具有黑素细胞病变。在其他以哺乳形式暴露的动物的皮肤上，没有任何类型的辐射引起的病变。受影响的男性来自暴露于来自Blak射线光源的最高总剂量 (140 kJ/m2) 的70个人。暂时将黑素细胞增生确定为潜在的黑色素瘤，但随着动物的衰老而缓慢消退。我们得出的结论是，在负鼠哺乳暴露系统中，与UVB相比，UVA诱导黑色素瘤的效力极低。与Ley的成人暴露模型相比，哺乳模型的UVA敏感性低 (Ley，R. D. [1997] Cancer Res。57,3682-3684)。

BACKGROUND & AIMS: :Oxytocin (OT) is essential for parturition and milk ejection, and OT-containing fibers are present in several regions of the brain and in the spinal cord. During lactation, activation of spinal cord neurons by suckling stimulation involves deep laminae III-X including sympathetic preganglionic neurons of the intermedio-medial cell column. In the present study, experiments were designed to determine if the suckling provided by the litter increased OT levels in the spinal cord of dams, as determined by competitive immunoassay. In addition, we investigated if OT fibers reach neurons of the spinal cord that are known to respond to suckling. The OT content was higher in the hypothalamus than in the spinal cord in animals from all experimental groups. After 6 h of pup separation, OT levels decreased and suckling for 5 min induced a significant increase of OT levels in the spinal cord. Double immunostaining for Fos and OT showed OT-positive fibers adjacent to neurons that had Fos-positive nuclei, located mostly in laminae III, IV, and X. The present data support the notion that OT is released within the spinal cord in response to suckling, suggesting a role for this peptide in modulating the afferent and/or efferent responses generated by suckling.

背景与目标： : 催产素 (OT) 对于分娩和乳汁排出至关重要，并且含OT的纤维存在于大脑和脊髓的多个区域。在哺乳期，哺乳刺激激活脊髓神经元涉及深层iii-x，包括中间细胞柱的交感神经节前神经元。在本研究中，设计了实验来确定垫料提供的哺乳是否增加了大坝脊髓中的OT水平，这是通过竞争性免疫测定法确定的。此外，我们研究了OT纤维是否到达已知对哺乳有反应的脊髓神经元。在所有实验组的动物中，下丘脑的OT含量均高于脊髓。幼崽分离6小时后，OT水平降低，哺乳5分钟后脊髓中OT水平显着增加。Fos和OT的双重免疫染色显示OT阳性纤维与具有Fos阳性核的神经元相邻，主要位于laminae III，IV和X中。目前的数据支持OT响应哺乳而在脊髓内释放的观点，这表明该肽在调节哺乳产生的传入和/或传出反应中的作用。

BACKGROUND & AIMS: :Intestinal amino acid (AA) transport is critical for the supply of AA to other tissues. Few studies regarding AA intestinal transport systems during the period from postnatal intense development of piglets until weaning are available. In the present study, we measured the intestinal expression of b(0,+)AT according to developmental stage using the suckling Huanjiang piglet model, and documented the effect of intra-uterine growth restriction (IUGR) on such expression using real-time PCR and Western blot analysis. Suckling piglets that recovered after IUGR and those with normal body weights (NBW) were used after birth or at 7, 14 and 21 d of age. Blood samples were used for the measurement of plasma AA concentrations, and the jejunum was collected for the measurement of b(0,+)AT expression. In NBW piglets, b(0,+)AT expression was markedly decreased from days 0 to 21 (P< 0.01) and remained at a low level during all the suckling periods. In IUGR piglets, there was a marked decrease in b(0,+)AT expression at birth, which remained lower, when compared with NBW piglets, during the suckling period. These results coincided with decreased plasma arginine concentration at birth and decreased lysine concentration in 21-d-old piglets (P< 0.05). It is concluded that the high expression of b(0,+)AT at birth decreases during the suckling period, and that IUGR is associated with decreased expression of this apical AA transporter. The possible causal relationship between decreased b(0,+)AT expression and lower body weight of IUGR piglets in the suckling period is discussed.

背景与目标： : 肠道氨基酸 (AA) 运输对于向其他组织供应AA至关重要。从仔猪出生后到断奶期间，关于AA肠道运输系统的研究很少。在本研究中，我们使用哺乳环江仔猪模型根据发育阶段测量了b(0，) 的肠道表达，并使用real-time PCR和Western blot记录了子宫内生长限制 (IUGR) 对这种表达的影响。IUGR后恢复的哺乳仔猪和体重正常 (NBW) 的仔猪在出生后或7、14和21 d时使用。血液样本用于测量血浆AA浓度，并收集空肠用于测量b(0，) AT表达。在NBW仔猪中，b(0，+)AT表达从第0天到第21天明显降低 (P< 0.01)，并在所有哺乳期间保持在低水平。在IUGR仔猪中，出生时表达的b(0，) 显着降低，与NBW仔猪相比，在哺乳期间仍然较低。这些结果与21 d仔猪出生时血浆精氨酸浓度降低和赖氨酸浓度降低相吻合 (P< 0.05)。结论是，在哺乳期间，出生时b(0，) 的高表达降低，并且IUGR与这种顶端AA转运蛋白的表达降低有关。讨论了乳期IUGR仔猪b(0，+)AT表达降低与体重降低之间的可能因果关系。

BACKGROUND & AIMS: :The postnatal development of intestine is associated with a decline in brush border lactase activity in rodents. This is similar to adulthood hypolactasia, a phenomenon prevalent in humans worldwide. In the present study, the effect of luminal proteases from adult rat intestine was studied in vitro on intestinal lactase activity in saline control, thyroxine, insulin and cortisone treated rat pups. Lactase levels were determined by enzyme analysis and Western blotting. mRNA levels encoding lactase were determined by Northern blotting. Administration of thyroxine for 4 days reduced (P<0.05) lactase activity, but insulin treatment had no effect in 8-day-old rat intestine. However, cortisone administration augmented (P<0.01) lactase activity, under these conditions. Western blot analysis showed decreased lactase signal corresponding to 220-kDa protein band in thyroxine treated animals. However, the intensity of lactase signal was high in cortisone treated animals compared to controls. mRNA levels encoding lactase showed a 6.8-kb mRNA transcript in saline and hormone treated rats. mRNA levels encoding lactase were increased in cortisone treated animals but were reduced in thyroxine injected pups compared to controls. Microvillus membranes from saline (P<0.01) and thyroxine (P<0.05) or insulin (P<0.01) treated rats upon incubation with luminal wash from adult rat intestine showed a significant decline in lactase activity. These findings suggest that thyroxine, insulin or cortisone induced changes in lactase expression in suckling rat intestine make it susceptible to luminal proteases, which may in part be responsible for observed maturational decline in lactase activity in adult rat intestine.

背景与目标： : 出生后肠道发育与啮齿动物刷状缘乳糖酶活性下降有关。这类似于成年性低乳酸症，这是全世界人类普遍存在的现象。在本研究中，在体外研究了成年大鼠肠道的luminal蛋白酶对盐水对照，甲状腺素，胰岛素和可的松处理的大鼠幼崽的肠乳糖酶活性的影响。通过酶分析和蛋白质印迹法确定乳糖酶水平。编码乳糖酶的mRNA水平通过Northern印迹测定。给予甲状腺素4天降低 (P<0.05) 乳糖酶活性，但胰岛素治疗对8天大的大鼠肠道没有影响。然而，在这些条件下，给予可的松增加 (P<0.01) 乳糖酶活性。Western印迹分析显示甲状腺素处理的动物中对应于220-kDa蛋白带的乳糖酶信号减少。然而，与对照组相比，可的松治疗的动物的乳糖酶信号强度很高。编码乳糖酶的mRNA水平在盐水和激素处理的大鼠中显示6.8-kb mRNA转录本。与对照组相比，经可的松处理的动物中编码乳糖酶的mRNA水平升高，但经甲状腺素注射的幼崽中编码乳糖酶的mRNA水平降低。用来自成年大鼠肠的管腔洗涤液孵育后，来自盐水 (P<0.01) 和甲状腺素 (P<0.05) 或胰岛素 (P<0.01) 处理的大鼠的微绒毛膜显示乳糖酶活性显着下降。这些发现表明，甲状腺素，胰岛素或可的松诱导乳鼠肠道中乳糖酶表达的变化使其对腔蛋白酶敏感，这可能部分是成年大鼠肠道中乳糖酶活性成熟下降的原因。

BACKGROUND & AIMS: :Currently, in pre and postnatal development studies or in juvenile rat studies, bone growth is assessed "for cause" by simple measurements of long bone length in vivo and at termination. This manuscript compares two radiographic methods for in vivo assessment of long bones in suckling rats; 2D imaging using a Faxitron™ and 3D imaging using μCT. This paper illustrates that it is possible to image the unanaesthetised postnatal day 1 rat by Faxitron™ using a simple Micropore™ tape restraint method. With isoflurane anaesthesia, it was possible to obtain high quality μCT images of pups from day of birth. No pups were rejected by their mothers following either technique. The Faxitron™ was straightforward and fast, however the μCT 3D images were of greater overall utility. Either method could be used for longitudinal investigation of long bone observations made previously in embryofetal development studies, or for other mechanistic work.

背景与目标： : 目前，在产前和产后发育研究或幼年大鼠研究中，通过简单测量体内和终止时的长骨长度来评估骨骼生长的 “原因”。本手稿比较了两种用于哺乳大鼠长骨体内评估的射线照相方法; 使用Faxitron进行2D成像™和使用 μ ct的3D成像。本文说明了通过Faxitron可以对未麻醉的出生后第1天的大鼠进行成像。™使用简单的微孔™胶带约束法。使用异氟醚麻醉，可以从出生之日起获得高质量的 μ ct幼崽图像。任何一种技术的母亲都没有拒绝幼崽。传真™简单明了，快速，但是 μ ct 3D图像具有更大的整体实用性。两种方法均可用于先前在胚胎发育研究中进行的长骨观察的纵向研究，或用于其他机械工作。

BACKGROUND & AIMS: Epidermal growth factor (EGF) is contained in breast milk, is transported intact across the gastrointestinal mucosa during the suckling period, retains its biological activity, and affects hepatic growth. Whether or not EGF also influences postnatal hepatic development by affecting nonparenchymal cells or by modifying intrahepatic blood is not clear. As a result, the effect of EGF on the hepatic microvasculature was studied in suckling rats fed rat milk substitute (RMS) with and without EGF (100 ng/ml, i.e. twice the normal intake in breast milk) between days 11 and 14 and compared to pups breast-fed for 14 days. The livers of anesthetized pups were examined by in vivo microscopy to determine the numbers of sinusoids with flow (SCF) in each of 10 microscopic fields and the numbers of phagocytic Kupffer cells (KC) in the same fields following an intraportal injection of fluorescent 1-micron latex particles. Phagocytic activity was expressed as the ratio KC/SCF. In pups fed RMS without EGF, SCF and KC/SCF was 75 and 45%, respectively, of that in breast-fed animals. The addition of EGF to the RMS restored SCF and KC/SCF nearly to the levels measured in breast-fed pups. Thus, the results suggest that milk-borne EGF plays a role in the development of KC phagocytic function and affects the amount of blood that perfuses the sinusoidal bed in the suckling.

背景与目标： 表皮生长因子 (EGF) 包含在母乳中，在哺乳期间完整地跨胃肠道粘膜转运，保留其生物学活性，并影响肝脏的生长。EGF是否还通过影响非实质细胞或通过改变肝内血液来影响产后肝脏发育尚不清楚。结果，在第11天和第14天之间，在哺乳大鼠中研究了EGF对肝微血管系统的影响，该哺乳大鼠饲喂有EGF和不饲喂EGF (100 ng/ml，即母乳中正常摄入量的两倍)，并与母乳喂养14天的幼崽进行比较。通过体内显微镜检查麻醉幼崽的肝脏，以确定在门内注射荧光后，在10个显微场中的每个场中流动的正弦曲线 (SCF) 的数量以及在相同场中的吞噬库普弗细胞 (KC) 的数量1微米乳胶颗粒。吞噬活性表示为KC/SCF的比率。在没有EGF的饲喂的幼崽中，SCF和KC/SCF分别为母乳喂养动物的RMS的75和45%。在RMS中添加EGF可使SCF和KC/SCF几乎恢复到母乳喂养幼崽的水平。因此，结果表明，牛奶传播的EGF在KC吞噬功能的发展中起作用，并影响在乳汁中灌注正弦床的血液量。

BACKGROUND & AIMS: :The effect of feeding 8% protein (low-protein; LP) diet to lactating rats has been studied on the absorption of macromolecules and the glycosylation of enterocytes in suckling animals. The absorption of 125I-labelled bovine serum albumin, gamma-globulin and alpha-lactalbumin was 24-314% more in pups nursed on mothers fed LP diet compared to the pair-fed controls. The observed enhancement in protein absorption was associated with a significant increase in the binding of these proteins to microvillus membranes (MVM). The sialic acid content of brush borders was unaltered but the fucose level was augmented (p less than 0.01) in pups nursed on rats fed LP diet. The binding of 125I-labelled wheat germ agglutinin and Ulex europeus agglutinin I to MVM was in agreement to the data on sialic acid and fucose levels of the membranes. The binding of peanut agglutinin to MVM was 30% low in pups from LP-diet-fed animals. The incorporation of (14C) D-mannose into MVM was essentially unaffected but that of (14C) N-acetylglucosamine was reduced in pups reared on mothers given LP diet. These findings suggest that the quality of maternal nutrition affects the absorption of macromolecules and the glycosylation in developing rat intestine.

背景与目标： : 研究了喂养8% 蛋白 (低蛋白; LP) 饮食对哺乳大鼠的大分子吸收和哺乳动物肠细胞糖基化的影响。与成对喂养的对照组相比，用LP饮食喂养的母亲喂养的幼崽对125i标记的牛血清白蛋白，γ-球蛋白和 α-乳白蛋白的吸收多24-314%。观察到的蛋白质吸收增强与这些蛋白质与微绒毛膜 (MVM) 的结合显着增加有关。饲喂LP饮食的幼崽中，刷状边界的唾液酸含量没有改变，但岩藻糖水平增加 (p小于0.01)。125i标记的小麦胚芽凝集素和Ulex europeus凝集素I与MVM的结合与膜的唾液酸和岩藻糖水平的数据一致。在来自LP饮食喂养的动物的幼崽中，花生凝集素与MVM的结合30% 低。在接受LP饮食的母亲饲养的幼崽中，(14C) D-甘露糖掺入MVM基本上不受影响，但 (14C) N-乙酰葡萄糖胺的掺入减少。这些发现表明，母体营养的质量会影响发育中的大鼠肠道中大分子的吸收和糖基化。

BACKGROUND & AIMS: :The modification induced by interferon (IFN) in brown adipose tissue (BAT) was studied by high spatial resolution magnetic resonance imaging (MRI), histology, and transmission electron microscopy (TEM). In IFN-treated mice, at MRI, the interscapular BAT was slightly enlarged and showed non-homogeneous areas of lipid accumulation. The thickness of the subcutaneous white adipose tissue was reduced with respect to control mice. In the liver, MRI showed a lipid accumulation. In IFN-treated mice, by light microscopy, brown adipocytes showed a larger lipid deposit with respect to control mice. At TEM, in BAT, the mitochondria were reduced in number, smaller and the number of cristae was also significantly reduced with respect to the controls (9.1 +/- 1.5 vs 20.1 +/- 1.9, P < 0.01). The inclusions in the mitochondrial matrix were significantly less numerous in IFN-treated than in control animals (1.9 +/- 0.7 vs 0.9 +/- 0.7 for mitochondrial section, P < 0.01). Abnormalities of endoplasmic reticulum described in hepatocytes were not found in brown adipocytes of IFN-treated mice. The present work demonstrates that, in the BAT of suckling mice, IFN-treatment induces morphologic alterations and that brown adipocytes have MRI and TEM features resembling those found in the lipid laden BAT of aged animals.

背景与目标： : 通过高空间分辨率磁共振成像 (MRI)，组织学和透射电子显微镜 (TEM) 研究了干扰素 (IFN) 在棕色脂肪组织 (BAT) 中诱导的修饰。在IFN处理的小鼠中，在MRI上，肩胛间BAT略微增大，并显示出脂质积聚的非均质区域。相对于对照小鼠，皮下白色脂肪组织的厚度减少了。在肝脏中，MRI显示脂质积聚。在接受IFN处理的小鼠中，通过光学显微镜检查，相对于对照小鼠，棕色脂肪细胞显示出更大的脂质沉积。在TEM，在BAT中，相对于对照，线粒体数量减少，较小，并且cristae的数量也显着减少 (9.1/- 1.5 vs 20.1/- 1.9，P <0.01)。在IFN处理过的线粒体基质中的内含物明显少于对照动物 (线粒体切片的1.9/- 0.7 vs 0.9/- 0.7，P <0.01)。在IFN处理的小鼠的棕色脂肪细胞中未发现肝细胞中描述的内质网异常。目前的工作表明，在哺乳小鼠的蝙蝠中，IFN处理会诱导形态学改变，并且棕色脂肪细胞的MRI和TEM特征类似于老年动物的脂质蝙蝠中的MRI和TEM特征。

BACKGROUND & AIMS: Total pyruvate dehydrogenase complex activity is low in white adipose tissue during the suckling period and increases markedly at weaning on to a high-carbohydrate diet. This is concomitant with an increase in the E1 alpha, E1 beta and E2 subunit protein concentration and their respective mRNAs, suggesting a pretranslational control of this phenomenon. The most marked change is seen for the E1 alpha subunit (17-fold increase in protein concentration). The changes in pyruvate dehydrogenase complex activity and subunit abundance induced by weaning on to a high-carbohydrate diet are precluded if the animals are weaned on to a high-fat diet, suggesting that the nutritional and/or related hormonal changes rather than a developmental stage are responsible for the observed adipose-tissue pyruvate dehydrogenase complex pattern.

背景与目标： 在哺乳期间，白色脂肪组织中的丙酮酸脱氢酶复合物总活性较低，而在断奶为高碳水化合物饮食时显着增加。这伴随着E1 α，E1 β 和E2亚基蛋白浓度及其各自mrna的增加，表明这种现象的翻译前控制。最明显的变化是E1 α 亚基 (蛋白质浓度增加17倍)。如果动物断奶高脂饮食，则排除了因断奶而导致的丙酮酸脱氢酶复合物活性和亚单位丰度的变化，表明营养和/或相关的激素变化而不是发育阶段是观察到的脂肪组织丙酮酸脱氢酶复合物模式的原因。

BACKGROUND & AIMS: :It is well established that the suckling stimulus sensitizes or primes the anterior pituitary to PRL-releasing stimuli. It is also recognized that PRL-secreting cells from a given animal are not all alike but instead exhibit a considerable degree of functional heterogeneity. The goal of the present study was to determine whether the suckling-induced priming phenomenon is manifest at the cellular level by shifts in the relative abundance of various mammotrope subpopulations. This was accomplished by using reverse hemolytic plaque assays to evaluate the secretory characteristics of individual PRL secretors derived from lactating rats either before or after the transient application of a suckling stimulus. Groups of day 10 lactating rats separated from their litters for 4 h were either killed immediately or were reunited briefly (10 min) with their pups before death. Adenohypophyseal cells obtained after trypsin dispersion were then subjected to plaque assays for PRL. Mammotropes derived from suckled rats were, on average, considerably more responsive to the stimulatory actions of TRH and angiotensin II and less susceptible to inhibition by dopamine. Mammotropes from nonsuckled rats exhibited a bimodal frequency distribution in which plaques from the second mode were roughly 6-8 times larger (released considerably more PRL) than those from the first. Superimposition of suckling (or in vitro treatment with dopamine) caused the second mode to disappear. Suckling also enhanced greatly the fraction of PRL cells that shifted from the first to the second mode (i.e. released more hormone) after treatment with TRH or angiotensin II. Taken together, our results demonstrate that the suckling-induced sensitization of pituitary tissue to PRL-releasing stimuli is manifest at the cellular level as proportional shifts toward those cells most responsive to stimulatory secretagogues and away from those most susceptible to inhibition by dopamine.

背景与目标： : 众所周知，哺乳刺激使垂体前叶对PRL释放刺激敏感或引发。还认识到，来自给定动物的PRL分泌细胞并非全部相同，而是表现出相当程度的功能异质性。本研究的目的是确定哺乳诱导的引发现象是否在细胞水平上表现为各种猛犸象亚群相对丰度的变化。这是通过使用反向溶血斑块测定法来评估在短暂施加乳汁刺激之前或之后源自泌乳大鼠的单个PRL分泌物的分泌特性来实现的。与幼仔分开4小时的第10天哺乳期大鼠组被立即杀死或在死亡前与幼崽短暂团聚 (10分钟)。然后对胰蛋白酶分散后获得的腺垂体细胞进行PRL的斑块分析。平均而言，来自乳鼠的猛犸象对TRH和血管紧张素II的刺激作用的反应要高得多，并且不易受到多巴胺的抑制。来自未哺乳大鼠的猛犸象表现出双峰频率分布，其中第二种模式的斑块比第一种模式的斑块大约6-8倍 (释放的PRL明显更多)。乳汁的叠加 (或用多巴胺进行体外治疗) 导致第二种模式消失。在用TRH或血管紧张素II治疗后，哺乳还大大增强了从第一种模式转变为第二种模式 (即释放更多激素) 的PRL细胞的比例。综合而言，我们的结果表明，哺乳诱导的垂体组织对PRL释放刺激的敏感性在细胞水平上表现为向对刺激性促分泌剂最有反应的细胞成比例地转移，而远离那些最易受多巴胺抑制的细胞。