• Journal of Nutrition and Health
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• v.25 no.7
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• pp.569-577
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• 1992

To study the effects of the age and the dietary protein content on Ca metabolism male rats of 1 month 6 month 12 month of age were fed experimental diets containing 5%, 15% or 50% casein for 4 weeks. Food and ca intake were higher in old rats and in high protein groups. The weight ash and Ca contents of femur and tibia were higher in old rats. The higher dietary protein level resulted in higher skeletal weigh ash and Ca contents. But high protein diet(50% casein) lead to reduced bone mineral density(ash/dry bone weight) and Ca density(Ca/dry bone weight) in 1 month old rats. Low protein diet(5% casein) on the other hand reduced the bone growth even though the bone density was higher in this group. The ill effect of low protein diet was not evident in 12 month old rats. Glomerular filteration rate(GFR) and urinary Ca excretionincreased with age and with dietary protein level especially in 12 month old rats. Serum immunoreactive parathyroid hormone(iPTH) level tended to be higher in aged rats but was not affected by dietary protein level except 1 month old rats where 50% protein group showed significantly higher value. This study showed that the dietary protein level seemed to have different effect on Ca metabo-lism in rats of different age., The low bone density in the high protein group of growing rats may be due to the higher iPTH level and increased urinary Ca. The dietary protein level however had no effects on the bone composition in aged rats even though the higher urinary Ca excretion. In conclusion this study suggests that high protein intake from young may lead to less peak bone mass and to increase the bone loss in later years, which would increase the risk for osteporosis.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.6
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• pp.531-536
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• 2013

Interstitial cells of Cajal (ICCs) from the urinary bladder regulate detrusor smooth muscle activities. We cultured ICCs from the urinary bladder of mice and performed patch clamp and intracellular $Ca^{2+}$ ($[Ca^{2+}]_i$) imaging to investigate whether cultured ICCs can be a valuable tool for cellular functional studies. The cultured ICCs displayed two types of spontaneous electrical activities which are similar to those recorded in intact bladder tissues. Spontaneous electrical activities of cultured ICCs were nifedipine-sensitive. Carbachol and ATP, both excitatory neurotransmitters in the urinary bladder, depolarized the membrane and increased the frequency of spike potentials. Carbachol increased $[Ca^{2+}]_i$ oscillations and basal $Ca^{2+}$ levels, which were blocked by atropine. These results suggest that cultured ICCs from the urinary bladder retain rhythmic phenotypes similar to the spontaneous electrical activities recorded from the intact urinary bladder. Therefore, we suggest that cultured ICCs from the urinary bladder may be useful for cellular and molecular studies of ICCs.

• Journal of Nutrition and Health
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• v.30 no.2
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• pp.170-176
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• 1997

Twenty two hypertensive and thirty normotensive in-patients were participated in this study to investigate the relationship between plasma renin activity and metabolism of Ca and Na, Prior to pharmacological treatments, renin activity, aldosterone and parathyroid hormone(PTH) levels were measured from the fasting blood samles. Twenty four hour urine samples were collected to analyze urinary levels of creatinine, Ca, Na and K. Habitual intake of Na and Ca were also measured for hypertensive and normotensive patients. Hypertensive subjects were classified into higher reinin hypertensive (HH), medium renin hypertensive(MH) and low renin hypertensive (LH) group according to their renin activities. PTH level of LH group was the highest among three hypertensive groups. It appeared that aldosterone levels of HH group were significantly higher than LH or MH groups(p<0.05). However there were no significan시 differences in aldosterone level between LH group and normotensive group. Habitual intake of Na and Ca were highest in LH group but lowest in HH group, however, they were not statistically different. Positive correlations of systolic blood pressure with PTH(r=0.2597) and aldosterone(r=0.26480existed(p<0.05). Urinary Ca level was positively correlated with urinary Na(r=0.5619), K(r=0.4533) and habitual Na intake(r=0.3253). Above results suggested the possible relationships among renin activity, habitual Ca intake and Na intake and suggested a further study on the interrelationship between the hormonal control of Ca and Na metabolism and blood pressure in hypertension.

• Journal of Nutrition and Health
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• v.31 no.6
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• pp.1039-1048
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• 1998

It has been reported that boron may be beneficial for optimal calcium metabolism and, thus, optimal bone metabolism. Therefore, we designed a study to determine the effect of boron supplementation on Ca and bone metabolism in rats. The rats of 80-l40g body weight were given a control(0ug), 5$\mu\textrm{g}$, 10$\mu\textrm{g}$, 20$\mu\textrm{g}$, 40$\mu\textrm{g}$, or 80$\mu\textrm{g}$ boron supplement per Is diet for 4-weeks. The results are summarized as follows. There were no differences in total food intake and weight gain among the experimental groups. fecal Ca excretion, urinary Ca excretion, apparent Ca absorption, Ca retention, serum alkaline phosphatase activity, and urinary hydroxyproline were not affected by boron supplementation. There was no difference in serum creatinine. Whereas, urinary creatinine excretion was increased with increasing boron supplementation, and conse-quently creatinine clearance was increased with boron supplementation. No differences were found in length, weight, density, Ca content of femur and scapular. The findings suggest that boron supplementation was not effective in Ca and bone metabolism in growing rats fed normal Ca diet. (Korean J Nutrition 31(6) : 1039-1048, 1998)

• Journal of Nutrition and Health
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• v.36 no.1
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• pp.75-82
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• 2003

It has been considered that high Na intake, and low Ca/K intake are related to the incidence of hypertension. In this preliminary study, dietary Na, K, and Ca intake and their urinary excretion in rural area in Kyungpook province were measured to recognize the relationship between those blood pressure-related minerals and blood pressure regulation in elderly people in rural area of South Korea. Sixty eight subjects (male 39, female 29) aged over 60 were randomly selected in rural area in South Korea. Blood pressure and soup saltness were measured, and dietary intake using 24 hours recall and urinary excretion of Na, K and Ca were measured. Depending on the blood pressure level, the data were analyzed using non-parametric ANOVA of Kruskal Wallis analysis on the basis of categorizing of one of four blood pressure groups, such as normal, high normal, hypertension I and hypertension II. Mean systolic (124.2$\pm$15.1 mmHg) and diastolic (79.0$\pm$10.2 mmHg) blood pressures were within the normal range. Soup saltiness and systolic pressure was positively correlated (p < 0.05). Even without statistical significance, dietary Na intake was higher in the upper systolic blood pressure groups then in the lower ones, which suggested higher Na intake caused the increase of blood pressure. No consistency was shown between the urinary concentration of Na, K, Ca level and blood pressure level, respectively. From the results of this study, it is assumed that high Na intake might be related to the incidence of hypertension. Further study with large sample size is needed to supplement the limitation of this preliminary study. (Korean J Nutrition 36 (1) : 75-82, 2003)

• Journal of Nutrition and Health
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• v.26 no.6
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• pp.728-742
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• 1993

The effects of dietary calcium levels on the blood pressure and calcium metabolism were investigated. Nine normotensive female college students having hypertention family history were participated in 4-week dietary expeiments. They were provided with either high Ca diet (HCa, average 797mg/day) or low Ca diet(LCa, average 225mg/day) during two weeks, each, consecutively. Sodium amounts of the body diets were 3566~4022mg/day, which were ordinary sodium intake levels in Korea. After the HCa, systolic blood pressures(SBR) in both seated and isogrip-seated postitions were decreased by about 2.5mgHg, comparing with those after the LCa(p<.05). Diastoilc blood pressures(DBP) were not changed by dietary calcium levels. Serum total Ca, ionized Ca, Mg and P levels and Ca/Mg ratio were not different between the HCa and the LCa. Serum parathyroid hormone(PTH) levels were similar between two diets, but individually in seven of nine subjects, the slightly lower values of PTH were observed after the HCa than after the LCa. Urinary excretion of Ca(p<.01), Mg(p<.05) and P(p<.1) were increased after the HCa comparing with the LCa, but Ca/Mg ratio were not different between the two diets. SBP was in positive correlations with boty urinary excretion of Ca(supine, r=.7356, p<.05) and urinary Ca/Mg ratio(isogrip-seated, r=.7483, p<.05). SBP was also negatively correlated with serum P level(supine, r=-.6930, p<.05) and DBP was in negative correlation with urinary P excretion(seated, r=-.8586, p<.01). Serum total and ionized Ca, Mg, Ca/Mg ratio were not significantly correlated with blood pressures.

• Journal of Nutrition and Health
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• v.30 no.7
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• pp.813-824
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• 1997

This study was designed to investigate the effect of dietary calcium and phosphate levels on calcium and bone metabolism in rats. The rats were divided into six groups and each of the groups was fed diets with different Ca/P ratios. The experimental periods were 5 weeks . There was no significant different difference in dietary intake, body weight gain, and organ weight among the groups with different calcium and phosphate intake levels. Fecal calcium excretion was not significantly different among the groups, but urinary calcium excretion was increased by the increase in Ca/P ratio. Fecal phosphate excretion was not different but urinary phosphate excretion was increased by the increase in dietary phosphate intake. There was no significant difference in serum alkaline phophatase activity and urinary hydroxyproline levels were not significantly different among the groups. The low calcium-high phosphate(0.25Ca-1.2% P) group showed the lowest total calcium content in femur and scapula. This may be due to it having the lowest Ca/P ratio among groups. The low calcium-high phosphate(0.2%Ca-1.2%P) group showed that mandible is almost lost and osteolyzed Harversian canal was expanded in femur. Results suggest that phosphate intake affects calcium and bone metabolism more with inadequate calcium nutrition that with adequate calcium intake. Thus , for normal bone growth and metabolism , adequate calcium intake and/or high Ca/P ratio are important.

• Journal of Nutrition and Health
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• v.39 no.1
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• pp.11-17
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• 2006

The effect of the level of casein phosphopeptide (CPP) on mineral (Ca and P) bioavailabilties and bone biomarker of aged ovariectomized (OVX) Sprague-Dawley rats were studied as a model for postmenopausal bone loss. Forty five Spargue dawley rats, 220-230 g of body weight were fed a control diet (AIN 93M) or containing different level of CPP diet for 7 weeks: $0\%$ (sham control; SC, OVX control; OC), $1\%$ (OVX low CPP diet: OL), $2\%$ (OVX medium CPP diet; OM), $3\%$ (OVX high CPP diet; OH) Ca absorption was unaffected by increasing CPP content from 0 to $3\%$. Urinary Ca excretion was increased by OVX, and decreased by CPP significantly (p < 0.05) with no evident doserelationship. The urinary P excretion was increased by CPP intake in OVX rats. The fecal excretion of P given CPP decreased in OVX with dose dependent manner. Ca and P contents of femur significantly increased by adding 2 or $3\%$ of CPP when compared with OC group and OL group (p < 0.05). There were no significant differences in serum alkaline phosphatase activity and c-terminal telopeptide excretion in experimental groups. Although ovariectomy induced the increase in urinary c-terminal telopeptide excretion, 2 or $3\%$ of CPP in the diet decreased urinary c-terminal telopetide excretion significantly. These finding suggest the usefulness of CPP in the prevention of postmenopausal bone loss by decreasing urinary Ca excretion and bone resorption. Over 2 percent of CPP in the diet was effective to prevent postmenopausal bone loss.

• Journal of Nutrition and Health
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• v.28 no.4
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• pp.309-320
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• 1995

The purpose of this research was to investigate the effect of calcium levels(50, 100 and 200% of requirement) on metabolism of Ca, Na and K in Young and adult female rats for 3 weeks. There was no significant difference in feed intake, body weight gain and feed efficiency ratio among the groups of different Ca intake level. Serum Na level of high-Ca group was significantly lower than that of low-Ca or normal-Ca group in Young rats. There was no significant difference in liver Ca and K contents among the groups of different Ca intake levels. But, Na content in liver was decreased by the increase of dietary Ca intake. Ca content in kidney of high-Ca group in young rats and normal-Ca group in adult rats were significantly higher than those of other groups. Na content in kidney of low-Ca group was lower than those of normal-Ca and high-Ca groups. Urinary excretions of Na and K and fecal excretion of Ca were increased by the increase of dietary Ca intake. But, fecal excretions of Na and K were not affected by dietary Ca intake. According to this study, it was found that the high Ca consumption promotes excretions of fecal Ca and urinary Na and K in rats. The study verifies the need for more study on the interrelationship among Ca, Na and K metabolism and bood pressure.

• The Korean Journal of Physiology and Pharmacology
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• v.3 no.2
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• pp.207-213
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• 1999

To examine individual variation in drug metabolism catalyzed by flavin-containing monooxygenase (FMO), 179 Korean volunteers' urinary molar concentration ratio of theobromine (TB) and caffeine (CA) was determined. Their urine was collected for 1 hr (between 4 and 5 hrs) after they drank a cup of coffee containing 115 mg CA and analyzed by an HPLC system. The lowest TB/CA ratio obtained was 0.40, the highest ratio was 15.17 (38-fold difference), and the median ratio for all subjects was 1.87. The mean was 2.66 with 2.36 S.D.. In 134 nonsmokers, the mean ratio was $2.35{\pm}1.93,$ that of 51 males was $2.30{\pm}2.26$ and 83 females was $2.37{\pm}1.85,$ respectively. There was no significant gender difference in the obtained TB/CA ratio (Mann-Whitney test; p=0.518). There were no smokers among the 83 female volunteers. In the remaining 96 male subjects, the ratio obtained in 51 nonsmokers was $2.30{\pm}2.06$ and that of 45 smokers was $3.62{\pm}3.19.$ This indicated that the TB/CA ratio was increased significantly in smokers (p=0.007). However, when the TB/CA ratios (FMO activity) obtained in all 179 Korean volunteers are compared with the urinary concentration ratios of paraxanthine (PX) plus 1,7-dimethylurate (17U) to CA (CYP1A2 activity), there was a weak but significant correlation (Pearson's correlation coefficient test; $r^2=0.28,$ p＜0.0001). This indicates that, although the urinary TB/CA ratio mostly represents FMO activity, minor contribution by CYP1A2 activity cannot be ignored. In conclusion, the FMO activity measured by taking the urinary TB/CA ratio from normal healthy Korean volunteers shows marked individual variations without significant gender differences and the increased TB/CA ratio observed in cigarette smokers may have been caused by the increased CYP1A2 activity.