• 한국환경보건학회지
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• 제46권4호
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• pp.368-375
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• 2020

Objectives: Some animal studies have reported that methyl mercury causes developmental toxicities such as placental and fetal weight loss, but the mechanism is still unclear. This study aimed to investigate the developmental toxicities of methyl mercury, focusing on placental endocrine function and fetal growth retardation in rats. Methods: Positively same-time-mated female Sprague-Dawley rats were purchased on gestational day (GD) eight and treated with 0, 5, 10 and 20 ppm of methyl mercury (n=5) dissolved in tap water from GD eight through 19. During treatment, the drinking water (methyl mercury) intake and body weight of each pregnant rat was measured daily. On day 19, caesarean sections were performed and blood samples were collected. Developmental data such as placental and fetal weights, fetus numbers, and placental efficiency (fetal weight/placental weight) were also collected. Placental prolactin-growth hormone (PRL-GH) family, such as placental lactogen (PL) -Iv, II, and prolactin-like protein (PLP) -B, levels in serum were analyzed by ELISA. Also, placental tissues were assigned to histochemistry. Results: The mean cumulative methyl mercury exposure for the 5, 10, and 20 ppm groups were 2.37, 4.63, and 9.66 mg, respectively. The mean daily exposure of the 5, 10, and 20 ppm groups were 0.24, 0.47, and 0.97 mg, respectively. Maternal body weight increased in accordance with GD. There was no significant difference in weight gain among the experimental groups. Histopathologic changes were not observed in placental tissues among the experimental groups. However, mean placental and fetal weights were lower in the 10 and 20 ppm exposed groups compared to the control. Placental efficiency was also lower in the 10 and 20 ppm exposed groups compared to the control. Serum PL-Iv and II levels were lower in the 10 and 20 ppm exposed groups than the control, in accordance with the changing pattern of placental and fetal weights and placental efficiency. Conclusion: The inhibitory effects of methyl mercury on the serum levels of placental PRL-GH family such as PL-Iv and II may be secondary leads to the reduction of placental efficiency and fetal growth retardation in rats.

• 약학회지
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• 제38권5호
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• pp.602-607
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• 1994

Based upon the previous experiments showing that kidney and lung tissues of rat had relatively abundant bradykinin binding sites, we tried to characterize and determine the densities of the bradykinin binding sites in the rabbit kidney tissue and proximal tubular cells under different growing conditions. Among the kidney tissue renal medulla segments showed the highest bradykinin binding sites. To determine which growth factors are to add in the serum free culture medium to express selectively the bradykinin binding sites in the rabbit kidney proximal tubular cells, we tried so called hormone-deletion approach and in here insulin, hydrocortisone, transferrin, triiodothyronine and prostaglandin $E_1$ are examined. By performing receptor binding assay and determination of protein concentrations, we may conclude that the most required hormones in the expression for bradykinin binding sites are insulin and transferrin, and fetal bovine serum is shown to be less effective in this regard.

• Journal of Nutrition and Health
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• 제37권6호
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• pp.423-430
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• 2004

This study was performed to evaluate the effect of red-yeast-rice on bone metabolism in overiectomized (OVX) rats. Forty female Sprague-Dawley rats (body weight 210 $\pm$ 5 g, 9 weeks old age) were divided into two groups. One group were OVX, and the other group received sham operation (SHAM), and received either control diet (20％ casein) or a red-yeast-rice power supplemented diet (0.1％) for 9 weeks. And then each rat group was further divided into control diet (casein 20％) and red-yeast-rice powder supplemented (0.1％) diet group. All rats were fed on experimental diet and deionized water ad libitum for 9 weeks. Bone mineral density (BMD) and bone mineral content (BMC) were measured using PIXImus (GE Lunar Co, Wisconsin, USA) in spine and femur on 5, 9 weeks after feeding. The serum and urine concentrations of Ca and P were determined. Bone formation was measured by serum osteocalcin and alkaline phosphatase (ALP) concentrations. And bone resorption rate was measured by deoxypyridinoline (DPD) crosslinks immunoassay and corrected for creatinine. Serum osteocalcin, growth hormone, IGF-l and calcitonin were analyzed using radioimmunoassay kits. Urinary Ca and P excretion were not significantly different among the groups. Within the OVX group, the red-yeast-rice group had a lower crosslinks value than the casein group. Therefore the red-yeast-rice supplemented groups had a lower bone resorption ratio than the casein group in the ovariectomized rats. And, the red-yeast-rice group had significantly higher IGF-l hormone than casein group in ovariectomized rats. The red-yeast-rice group had higher spine bone mineral content than those of control group within the OVX groups. This study was an important first step in establishing that the observed beneficial effects of red-yeast-rice on bone, and this study also established the need for a study on the long-term effect of this supplement in a human.

• 한국가축번식학회지
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• 제21권2호
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• pp.197-205
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• 1997

Improved hypophysectomy technique and the efficacy of bGH in hypophysectomized female rats were studied as a basis for the function of endocrine gland and hormones. 1. With improved sublaryngeal a, pp.oach by hypophysectomy, 34 rats out of 40 were successfully hypophysectomized(more than 80% of success). The surgical time for hypophysectomy per rat was taken about 3.0$\pm$1.0 min. 2. For the effect of hypophysectomy and bGH on body weight gain among the 5 gruops of A, B, C, D, and E, the weight gains for A, B, C, D, and E, were 93g, 9.2g, 10.7g, 25.1g and 36.2g, respectively, which implied that hypophysectomy had a major effect on body weight. And also, the effect of bGH was paralleled with the level of bGH. There were significant difference between control and hypophysectomized groups, and between the bGH treated and bGH non-treated groups after hypophysectomy(p<0.01). 3. For the effect of hypophysectomy and bGH on the length of femur, tibia, humerus, and anterbrachi, longest was for A, shortest for B, and longer in order of C, D, and E. The A group was significantly longer than B, C, D, and E groups. The B group was shorter than C, D, and E groups(p<0.01). 4. For the effect of hypophysectomy and bGH on the weight of femur, tibia, humerus, and antebrachi, heaviest was for A, lightest for B, and heavier in order of C, D, and E. The A group was significantly heavier than B, C, D, and E groups. The B group was lighter than C, D, and E groups(p<0.01). 5. In changes of body length, and weights of liver and heart, A group was most drastically increased. Among the hypophysectomized groups, the change was increased in order of B, C, D, and E. Especially, the change of A group was significantly greater than B, C, D and E gruops. However, no significant differences were found among B, C, D, and E groups. 6. The hypophysectomy in rat had a significant effect on body growth. The effect of hormone was remarkably different depending upon the level of hormone. It was found that 300$\mu\textrm{g}$ of bGH/kg of body wt/day was slightly lower for normal growth.

• Asian-Australasian Journal of Animal Sciences
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• 제10권4호
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• pp.335-356
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• 1997

Injection of bovine growth hormone (bGH) to lactating dairy cows increases milk yield and yields of milk components including fat. It is generally believed that most of the anabolic effects derived from bGH in animal tissues are primarily mediated by IGF-1. IGF-1 is a strong anabolic peptide in the plasma of animals and exerts mitogenic and metabolic effects on target cells. Contrary to most protein hormones, the majority of IGF-1 in circulation is bound to the binding proteins (IGFBPs) which are known to be responsible for modifying the biological actions of IGF-1, thus making determinations of IGF-1 actions more difficult. On the other hand, fat is a major milk component and the greatest energy source in milk. Currently, the fat content of milk is one of the major criteria used in determining milk prices. It has been known that flavor and texture of dairy products are mainly affected by milk fat and its composition. Acetyl-CoA carboxylase (ACC) is the rate limiting enzyme which catalyzes the conversion of acetyl-CoA to malonyl-CoA for fatty acid synthesis in 1ipogenic tissues of animals including bovine lactating mammary glands. In addition to the short-tenn hormonal regulation of ACC by changes in the catalytic efficiency per enzyme molecule brought about by phosphorylation and dephosphorylation of the enzyme, the long-term hormonal regulation of ACC by changes in the number of enzyme molecules plays an essential role in control of ACC and lipogenesis. Insulin, at supraphysiological concentrations, binds to IGF-1 receptors, thereby mimicking the biological effects of IGF-1. The receptors for insulin and IGF-1 share structural and functional homology. Furthermore, epidermal growth factor increased ACC activity in rat hepatocytes and adipocytes. Therefore, it can be assumed that IGF-1 mediating bGH action may increase milk fat production by stimulation ACC with phosphorylation (short term) and/or increasing amounts of the enzyme proteins (long term). Consequently, the main purpose of this paper is to give the readers not only the galactopoietic effects of bGH, but also the insight of bGH action with regard to stimulating milk fat synthesis from the whole body to the molecular levels.

• Natural Product Sciences
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• 제19권4호
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• pp.303-310
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• 2013

Velvet deer antler (VDA) is well known oriental medicine claimed to have tonic activities as improving bone mineral density (BMD), immune-enhancing, rejuvenating and many other medicinal activities. Ossified deer antler (ODA) is bony product produced by over-calcification of deer antler due to late harvesting. The extraction efficiency of ODA by conventional boiling in water must be very poor due to bony nature, hence the reputations for the medicinal efficacies of ODA has been highly under-evaluated compared to that of VDA without any experimental evidences. Employing our new efficient water extraction process ($135^{\circ}C$), the extracts of ODA and VDA were analysed to compare the contents of bioactive components and the potencies of pharmacological activities. The results showed that; 1) The $135^{\circ}C$ extraction (autoclaving) of ODA gave highly increased amount of biomass, 120% more than the conventional extraction by 100-boiling, whereas the same treatment for VDA showed only 15% increased amount of biomass. 2) Feeding the ODA- or VDA-extracts to oophorectomized rats showed very potent BMD-recovering activity. 3) During the ossification of deer antler, the total collagen content was found to be increased by addition of type-1 to pre-existing type-2 collagen, but not replacement of type-2 to type-1 collagen. High titer of peptide hormones like growth hormone and IGF-1 were detected in the ODA- and VDA-extracts and also in the serum of ODA- or VDA-treated oophorectomized animals dose-dependently. Present experimental data will give a conclusion that folkloric poor reputations on ODA must be concerned only with poor extraction efficiency of conventional $100^{\circ}C$ water extraction and not based on the composition of bioactive substances of ODA.

• Archives of Pharmacal Research
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• 제26권11호
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• pp.929-936
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• 2003

Methanol extract (MeOH), n-hexane (Hx), chloroform ($CHCl_3$), ethyl acetate (EA), butanol (BuOH) and aqueous ($H_2O$) fractions of Eucommiae Cortex including geniposidic acid (GA), geniposide (GP) and aucubin (AU) were tested for their therapeutic efficacy on osteoporosis. The contents of GA, GP and AU in the cortex and leaf of Eucommia ulmoides Oliver were quantified by HPLC. The effect of Eucommiae Cortex on the induction of growth hormone (GH) release was studied by using rat pituitary cells. The proliferation of osteoblast-like cells increased by herbal extracts was assayed using a tetrazolium (MTT), alkaline phosphatase (ALP) activity, and [$^3H$]-proline incorporation assays. The inhibition of osteoclast was studied by using the coculture of mouse bone marrow cells and ST-2 cells. As a result, the GA, GP and AU were present in the cortex more than in the leaf of E. ulmoides Oliver. The MeOH (1mg/mL), Hx, $CHCl_3$ and EA fractions (each 20 $\mu$ g/mL) had potent induction of GH release. The $CHCl_3$ exhibited the potent proliferation of osteoblasts. The AU, GP and GA were increased proliferation of osteoblasts. In addition, GA ($IC_{50}: 4.43{\times}10^{-7}$M), AU and GP were significantly inhibited proliferation of osteoclast. In summary, it is thought that the components in a part of the fractions of Eucommiae Cortex participate in each step of mechanism for activating osteoblast to facilitate osteogenesis, and suppress osteoclast activity to inhibit osteolysis.

• The Korean Journal of Physiology and Pharmacology
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• 제7권2호
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• pp.79-84
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• 2003

We have previously reported that expression of the somatostatin receptor subtypes, sst1-5, is differentially regulated by growth hormone (GH)-releasing hormone (GHRH) and forskolin (FSK), in vitro. GHRH binds to membrane receptors selectively located on pituitary somatotropes, activates adenylyl cyclase (AC) and increases sst1 and sst2 and decreases sst5 mRNA levels, without significantly altering the expression of sst3 and sst4. In contrast FSK directly activates AC in all pituitary cell types and increases sst1 and sst2 mRNA levels and decreases sst3, sst4 and sst5 expression. Two explanations could account for these differential effects: 1) GHRH inhibits sst3 and sst4 expression in somatotropes, but this inhibitory effect is masked by expression of these receptors in unresponsive pituitary cell types, and 2) FSK inhibits sst3 and sst4 expression levels in pituitary cell types other than somatotropes. To differentiate between these two possibilities, somatotropes were sequentially labeled with monkey anti-rat GH antiserum, biotinylated goat anti-human IgG, and streptavidin-PE and subsequently purified by fluorescent-activated cell sorting (FACS). The resultant cell population consisted of 95% somatotropes, as determined by GH immunohistochemistry using a primary GH antiserum different from that used for FACS sorting. Purified somatotropes were cultured for 3 days and treated for 4 h with vehicle, GHRH (10 nM) or FSK ($10{\mu}M$). Total RNA was isolated by column extraction and specific receptor mRNA levels were determined by semi-quantitative multiplex RT-PCR. Under basal conditions, the relative expression levels of the various somatostatin receptor subtypes were sst2＞sst5＞sst3=sst1＞ sst4. GHRH treatment increased sst1 and sst2 mRNA levels and decreased sst3, sst4 and sst5 mRNA levels in purified somatotropes, comparable to the effects of FSK on purified somatotropes and mixed pituitary cell cultures. Taken together, these results demonstrate that GHRH acutely modulates the expression of all somatostatin receptor subtypes within GH-producing cells and its actions are likely mediated by activation of AC.

• Archives of Pharmacal Research
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• 제20권4호
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• pp.297-305
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• 1997

A new serum-free defined medium was developed that supports the growth of normal rat mammary epithelial cells. Mammary organoids from the glands of female F344 rats were cultured in a serum-free medium. Monolayer culture colonies developed within a week and remained viable for months in culture. Upon subculture of one-week-old primary colonies, almost the same morphology of colonies was developed. The scrape loading/dye transfer technique showed that most of colonies that developed in a serum-free medium containing EGF, human transferrin, insulin, and hydrocortisone (basal serum-free medium, BSFM) failed to show cell-cell communication. However, colonies cultured in BSFM supplemented with prolactin, $E_2$, and progesterone (complete hormone serum-free medium, CHSFM) showed cell-cell communication at 14 days of primary culture or of subculture. By flow cytometry with FITCPNA and PE-anti-Thy-1.1 monoclonal antibody, we distinguished four RMEC subpopulations in cultures in both media: Thy-1.1+ cells, PNA+ cells, cells negative to both reagents and cells positive to both reagents. It is likely that combined prolactin, cortisol, and insulin in CHSFM stimulate terminal differentiation of clonogenic cells.

• Asian-Australasian Journal of Animal Sciences
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• 제15권4호
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• pp.570-575
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• 2002

Effects of active immunization against native 14-mer somatostatin (SRIF, somatotropin releasing inhibiting factor) and its two 14-mer-somatostatin analogues on the milk production in rat mammary cells were studied. Native SRIF, Tyr11-somatostatin (Tyr11-SRIF), and D-Trp8, D-Cys14-somatostatin (Trp8Cys14-SRIF) were conjugated to bovine serum albumin (BSA) for immunogen preparation. Twenty-four female Sprague-Dawley rats were divided into four groups and immunized against saline (Control), SRIF, Tyr11-SRIF, and Trp8Cys14-SRIF at five weeks of age. Booster immunizations were performed at 7, 9, and 11 weeks of age. SRIFimmunized rats were mated at 10 weeks of age. The blood and mammary glands were collected at day 15 post-pregnancy and -lactation. To measure the amount of milk protein synthesis in the mammary gland, mammary cells isolated from the pregnant and the lactating rats, were cultured in the presence of $^3H$-lysine. No significant differences in growth performance, concentration of growth hormone in the circulation, and the amount of milk protein synthesis were observed among the groups. Inductive levels of serum anti-SRIF antibody in the SRIF and Tyr11-SRIF groups but not in the Trp8Cys14-SRIF group, were significantly higher than that of the control group during the pregnancy and lactation periods. The result suggests that active immunization against native 14-mer SRIF and Tyr11-SRIF was able to induce anti-SRIF antibodies, but did not affect the milk protein synthesis.