Calcium metabolism in dairy sheep

1984 ◽  
Vol 102 (3) ◽  
pp. 601-608 ◽  
Author(s):  
S. Economides
Keyword(s):  
Calcium Intake ◽  
Calcium Metabolism ◽  
Dry Matter ◽  
Calcium Absorption ◽  
Urinary Calcium ◽  
Calcium Balance ◽  
Dairy Sheep ◽  
Deficient Diet ◽  
Pregnant Sheep ◽  
Calcium Loss

SummaryCalcium metabolism in dairy sheep was studied using radioisotope and balance techniques. The rate of calcium absorption increased, but the efficiency of calcium absorption decreased, with increasing calcium intake in dry sheep. Endogenous faecal and urinary calcium losses, and the rate of calcium absorption, decreased, but the efficiency of calcium absorption increased in pregnant sheep given a calcium-deficient diet. The rate and the efficiency of calcium absorption and the calcium balance of lactating ewes were not influenced by the prepartum level of calcium intake, when calcium intake in early lactation was high. Endogenous faecal calcium loss was related to dry-matter intake, and total faecal calcium loss was related to calcium intake.

Calcium Balance in Osteoporotic Patients on Long-Term Oral Calcium Therapy with and without Sex Hormones

1982 ◽  
Vol 62 (2) ◽  
pp. 221-226 ◽  
Author(s):  
N. C. Thalassinos ◽  
D. H. Gutteridge ◽  
G. F. Joplin ◽  
T. R. Fraser
Keyword(s):  
Calcium Intake ◽  
Calcium Absorption ◽  
Concomitant Administration ◽  
Urinary Calcium ◽  
Calcium Balance ◽  
Total Calcium ◽  
High Calcium Intake ◽  
Oral Calcium ◽  
High Calcium

1. The effect of a high calcium intake (1 mmol day−1 kg−1) alone or with the concomitant administration of oestradiol and testosterone derivatives was monitored by serial calcium balances in 48 patients with osteoporosis of various types. 2. On high calcium alone there was an increase (P < 0.001) in both total calcium balance and net calcium absorption as compared with values on a simulated home intake. This effect was sustained for periods up to 10 years (mean 3.5 years) by the addition of the hormones. 3. Discontinuation of the hormones (only) produced a significant decrease in both calcium balance and nett absorption but both were still increased when compared with the initial values under simulated home calcium intake. 4. No significant change in the urinary calcium output was observed under any of the regimens.

scholarly journals Calcium and caffeine interaction in increased calcium balance in ovariectomized rats

2013 ◽  
Vol 26 (3) ◽  
pp. 313-322
Author(s):  
Sandra Tavares da Silva ◽  
Neuza Maria Brunoro Costa ◽  
Frederico Souzalima Caldoncelli Franco ◽  
Antônio José Natali
Keyword(s):  
Calcium Intake ◽  
Calcium Absorption ◽  
Urinary Calcium ◽  
Deionized Water ◽  
Ovariectomized Rats ◽  
Caffeine Intake ◽  
Calcium Excretion ◽  
Calcium Balance ◽  
Negative Effects ◽  
Ad Libitum

OBJECTIVE: This study investigated the effects of caffeine intake associated with inadequate or adequate calcium intake in laparotomized or ovariectomized rats by means of the calcium balance. Forty adults Wistar rats were ovariectomized or laparotomized. METHODS: The animals (n=40) were randomly placed in eight groups receiving the AIN-93 diet with 100% or 50% of the recommended calcium intake with or without added caffeine (6mg/kg/day). The animals were kept in individuals metabolic cages at a temperature of 24°±2ºC, light/dark cycles of 12/12 hours, and deionized water available ad libitum. On the 8th week of the experiment, food consumption was measured and 24-hour urine and 4-day feces were collected to determine calcium balance [Balance=Ca intake-(Urinary Ca+Fecal Ca)]. RESULTS: Animals with adequate calcium intake presented higher balances and rates of calcium absorption and retention (p<0.05) than those with inadequate calcium intake, regardless of caffeine intake (p<0.05). Caffeine intake did not affect urinary calcium excretion but increased balance (p<0.05) in the groups with adequate calcium intake. CONCLUSION: Adequate calcium intake attenuated the negative effects of estrogen deficiency and improved calcium balance even in the presence of caffeine.

Action of 1,25-dihydroxyvitamin D3 and a diphosphonate on calcium metabolism in rats

1975 ◽  
Vol 229 (2) ◽  
pp. 402-408 ◽  
Author(s):  
JP Bonjour ◽  
U Trechsel ◽  
H Fleisch ◽  
R Schenk ◽  
HF DeLuca ◽  
...  
Keyword(s):  
Calcium Metabolism ◽  
Calcium Absorption ◽  
Bone Mineralization ◽  
Concomitant Administration ◽  
Urinary Calcium ◽  
Intestinal Calcium Absorption ◽  
Bone Morphology ◽  
Dihydroxyvitamin D3 ◽  
Calcium Retention ◽  
Endogenous Production

The effect of 1,25-dihydroxycholecalciferol (1,25-(OH)2D3) on Ca balance, 45Ca kinetics, and bone morphology has been studied in control rats and rats given disodium ethane-1-hydroxy-1,1-diphosphonate (EHDP), 10 mg P/kg sc per day. This large dose of EHDP is known to inhibit bone mineralization and intestinal calcium absorption and to depress the endogenous production of 1,25-(OH)2D3. In conctrol rats, 1,25-(OH)2D3 increased intestinal calcium absorption. However, in contrast to the enhanced calcium absorption that results from an augmentation of dietary calcium, the 1,25(OH)2D3-induced augmentation of calcium absorption does not lead to a rise in calcium retention, the intestinal effect being matched by an increased excretion of urinary calcium. The EHDP-induced decrease of intestinal calcium absorption could be completely prevented by the concomitant administration of 1,25-(OH)2D3 but not the inhibition of bone mineralization. Therefore, in contrast to the impairment of calcium absorption, that of bone mineralization brought about by large doses of EHDP cannot be merely attributed to a decreased production of 1,25-(OH)2D3.

scholarly journals Calcium Absorptive Efficiency Is Positively Related to Body Size

2005 ◽  
Vol 90 (9) ◽  
pp. 5118-5120 ◽  
Author(s):  
M. Janet Barger-Lux ◽  
Robert P. Heaney
Keyword(s):  
Body Size ◽  
Calcium Intake ◽  
Calcium Absorption ◽  
Absorption Efficiency ◽  
Calcium Balance ◽  
Data Set ◽  
Total Variability ◽  
Predicted Values ◽  
Metabolic Unit ◽  
The Relationship

Abstract Background: Calcium absorption efficiency is a more important determinant of calcium balance than calcium intake itself. The sources of variability in absorptive performance are only partly elucidated. Purpose: The aim of the study was to explore the relationship between body size and calcium absorption efficiency. Design and Setting: Metabolic studies were performed on an inpatient metabolic unit in an academic health sciences center. Subjects: One hundred seventy-eight women, with an average age of 50.2 yr, were studied from one to five times and yielded an aggregate data set containing 633 individual studies. Methods: Calcium absorption fraction was measured by the dual-tracer method. Observed values were expressed as residuals from predicted values for each woman’s actual calcium intake, using the previously published relationship between intake and absorption. Results: Absorption residuals were significantly positively correlated with height, weight, and surface area, and after adjusting for estrogen status, these body size variables accounted for approximately 4% of the total variability. Conclusion: The magnitude of the effect is such that a woman 1.8 m in height would absorb 30+% more calcium from a given intake than a woman 1.4 m tall.

Impaired body calcium metabolism with low bone density and compensatory colonic calcium absorption in cecectomized rats

2012 ◽  
Vol 302 (7) ◽  
pp. E852-E863 ◽  
Author(s):  
Prapaporn Jongwattanapisan ◽  
Panan Suntornsaratoon ◽  
Kannikar Wongdee ◽  
Nitita Dorkkam ◽  
Nateetip Krishnamra ◽  
...  
Keyword(s):  
Epithelial Cells ◽  
Calcium Transport ◽  
Calcium Metabolism ◽  
Calcium Absorption ◽  
Calcium Excretion ◽  
Compensatory Mechanism ◽  
Calcium Balance ◽  
Balance Study ◽  
Colonic Epithelial Cells ◽  
Calbindin D

An earlier study reported that cecal calcium absorption contributes less than 10% of total calcium absorbed by the intestine, although the cecum has the highest calcium transport rate compared with other intestinal segments. Thus, the physiological significance of the cecum pertaining to body calcium metabolism remains elusive. Herein, a 4-wk calcium balance study in cecectomized rats revealed an increase in fecal calcium loss with marked decreases in fractional calcium absorption and urinary calcium excretion only in the early days post-operation, suggesting the presence of a compensatory mechanism to minimize intestinal calcium wasting. Further investigation in cecectomized rats showed that active calcium transport was enhanced in the proximal colon but not in the small intestine, whereas passive calcium transport along the whole intestine was unaltered. Since apical exposure to calcium-sensing receptor (CaSR) agonists similarly increased proximal colonic calcium transport, activation of apical CaSR in colonic epithelial cells could have been involved in this hyperabsorption. Calcium transporter genes, i.e., TRPV6 and calbindin-D9k, were also upregulated in proximal colonic epithelial cells. Surprisingly, elevated serum parathyroid hormone levels and hyperphosphatemia were evident in cecectomized rats despite normal plasma calcium levels, suggesting that colonic compensation alone might be insufficient to maintain normocalcemia. Thus, massive bone loss occurred in both cortical and trabecular sites, including lumbar vertebrae, femora, and tibiae. The presence of compensatory colonic calcium hyperabsorption with pervasive osteopenia in cecectomized rats therefore corroborates that the cecum is extremely crucial for body calcium homeostasis.

Calcium metabolism in pregnancy

1989 ◽  
Vol 1 (2) ◽  
pp. 213-222 ◽  
Author(s):  
Barry NJ Walters
Keyword(s):  
Calcium Metabolism ◽  
Calcium Content ◽  
Maternal Serum ◽  
Term Infant ◽  
World Health ◽  
Human Breast Milk ◽  
Calcium Balance ◽  
The World ◽  
Calcium Loss ◽  
In Pregnancy

During pregnancy and lactation there are many changes in maternal calcium physiology which maintain homeostasis in the face of greatly altered calcium balance. In the course of fetal growth and development, 30g of calcium is incorporated into the fetus by term, an amount derived wholly from the maternal system. Most of this accumulates in the latter half of pregnancy, representing a net transfer of 200mg calcium/day (5mmoles). The fact that this is not achieved at the expense of the maternal skeleton is testimony to the conservative and protective adjustments that are seen in calcium metabolism in pregnancy. Furthermore, the changes must persist both in the puerperium and later when lactation presents a source of continuing maternal calcium loss to the suckling infant. The calcium content of human breast milk s i 6–9mmols calcium/l, two to three times the maternal serum level. In the course of one week a normal breast-fed at term infant takes two to three litres of milk, containing 10–30mmols of calcium. The maternal daily calcium intake recommended by the World Health Organization s i 1.25g (30mmol) of which only 25% is absorbed. Thus calcium loss from mother to baby is significant and may not be replaced by diet in many parts of the world.

Mechanism of chronic hypercalciuria with furosemide: increased calcium absorption

1986 ◽  
Vol 251 (1) ◽  
pp. F17-F24 ◽  
Author(s):  
D. A. Bushinsky ◽  
M. J. Favus ◽  
C. B. Langman ◽  
F. L. Coe
Keyword(s):  
Calcium Absorption ◽  
Chronic Administration ◽  
Urinary Calcium ◽  
Intestinal Calcium Absorption ◽  
Calcium Excretion ◽  
Calcium Balance ◽  
Urine Calcium ◽  
Calcium Diet ◽  
Filtered Load ◽  
Urine Calcium Excretion

Furosemide produces chronic hypercalciuria. The source of the additional urinary calcium is not known but must be either bone mineral or calcium absorbed by the intestine. Without bone calcium dissolution or increased absorption the filtered load of calcium would fall and urinary calcium excretion would return to pretreatment levels. To determine whether furosemide alters intestinal calcium absorption, we fed furosemide (75 mg . kg body-1 wt . day-1) to 11 rats eating 15 g/day of a 0.60% calcium diet. Compared with 11 control rats, furosemide increased urine calcium (15.6 +/- 0.8 mg/5 days vs. 4.1 +/- 0.3, P less than 0.001). Fecal calcium excretion fell (194 +/- 7 mg/5 days vs. 223 +/- 12, P less than 0.05), indicating an increase in intestinal calcium absorption sufficient to sustain the hypercalciuria. The increase in absorption occurred without an increase in the level of serum 1,25-dihydroxycholecalciferol (180 +/- 20 pg/ml vs. 220 +/- 16, furosemide vs. control, respectively, P = NS). To determine whether the intestinal effect of furosemide persists after the initial sodium diuresis abates, we analyzed only the last 3 days of balance. Again, rats fed furosemide had increased urine excretion and intestinal absorption of calcium, so that net calcium balance was not different from that of controls. Twelve additional rats were fed a 0.02% calcium diet to which 35 mg . kg body wt-1 . day-1 of furosemide was added. Compared with eleven controls, urine calcium increased and fecal calcium excretion again fell, but balance was not different. Chronic administration of furosemide increases intestinal calcium absorption enough to permit urine calcium excretion to remain elevated without the necessity for bone dissolution.

Effects of vitamin D receptor inactivation on the expression of calbindins and calcium metabolism

2001 ◽  
Vol 281 (3) ◽  
pp. E558-E564 ◽  
Author(s):  
Yan Chun Li ◽  
Merry J. G. Bolt ◽  
Li-Ping Cao ◽  
Michael D. Sitrin
Keyword(s):  
Vitamin D ◽  
Vitamin D Receptor ◽  
Calcium Level ◽  
Calcium Metabolism ◽  
Calcium Absorption ◽  
Urinary Calcium ◽  
Calcium Handling ◽  
Wild Type ◽  
Protein Levels ◽  
High Calcium

Hypocalcemia, rickets, and osteomalacia are major phenotypic abnormalities in vitamin D receptor (VDR)-null mice. In an attempt to understand the abnormal regulation of calcium metabolism in these animals, we examined the expression of calbindins (CaBP) as well as calcium handling in the intestine and kidney of VDR null mice. In adult VDR-null mice, intestinal and renal CaBP-D9k expression was reduced by 50 and 90%, respectively, at both the mRNA and protein levels compared with wild-type littermates, whereas renal CaBP-D28k expression was not significantly changed. Intestinal calcium absorption was measured by the rate of45Ca disappearance from the intestine after an oral dose of the isotope. 45Ca absorption was similar in VDR-null and wild-type mice, but the amount of 45Ca accumulated in the serum and bone was 3–4 times higher in wild-type mice than in VDR-null mice. Despite the hypocalcemia, the urinary excretion of calcium in VDR-null mice was not different from that in wild-type mice. Moreover, 1 wk of a high-calcium diet treatment that normalized the serum ionized calcium level of VDR-null mice increased the urinary calcium level of these mutant mice to twofold higher than that of wild-type mice on the same diet, suggesting impaired renal calcium conservation in VDR-null mice. These data demonstrate that renal CaBP-D9k, but not CaBP-D28k, is highly regulated by the VDR-mediated action of 1,25-dihydroxyvitamin D3. Furthermore, the results also suggest that impaired calcium conservation in the kidney may be the most important factor contributing to the development of hypocalcemia in VDR-null mice, and CaBP-D9k may be an important mediator of calcium reabsorption in the kidney.

scholarly journals A COMPERATIVE STUDY ON RATIO OF CALCIUM AND PHOSPHORUS IN SERUM AND URINE AMONG PRE AND POSTMENOPAUSAL WOMEN.

2020 ◽  
pp. 1-5
Author(s):  
Ewanmihaka Pakma ◽  
Apurba Sarkar ◽  
Suresh Babu
Keyword(s):  
Bone Mass ◽  
Calcium Intake ◽  
Absorption Rate ◽  
Peak Bone Mass ◽  
Calcium Absorption ◽  
Later Life ◽  
Urinary Calcium ◽  
Calcium Excretion ◽  
Urinary Creatinine ◽  
Calcium And Phosphorus

Osteoporosis is a bone disease resulting in reduction in bone mass and the bone become susceptible for fracture. The major factor involved in the development of osteoporosis includes, low calcium intake or decrease in Calcium absorption rate in aged population, bone strength in later life depends on development of bones earlier in life, adequate calcium intake during youth is essential to achieve peak bone mass. The Serum Calcium and Phosphorus, Urinary Calcium and Phosphorus were estimated by spectrophotometrically by O-cresolphthalein and Phosphomolybdate method respectively. Urinary creatinine was estimated by Spectrophotometric Jaffe’s reaction. In our study, Urinary Calcium excretion was significantly increased with that of premenopausal woman of Indian sub population. Present study is an attempt to underscore urinary calcium quantification does increase diagnostic sensitivity by measuring it as derive parameter – CCR. It could as well be considered as an indicator for therapeutic intervention by studying large pre and postmenopausal woman population.

The study of a physiological significance of prolactin in the regulation of calcium metabolism during pregnancy and lactation in rats

1998 ◽  
Vol 76 (2) ◽  
pp. 218-228 ◽  
Author(s):  
Sutada Lotinun ◽  
Liangchai Limlomwongse ◽  
Nateetip Krishnamra
Keyword(s):  
Body Weight ◽  
Calcium Metabolism ◽  
Turnover Rate ◽  
Calcium Absorption ◽  
Prolactin Secretion ◽  
Calcium Excretion ◽  
Calcium Balance ◽  
Total Calcium ◽  
Bone Calcium ◽  
Pregnancy And Lactation

Since a pharmacological dose of prolactin has previously been reported to enhance calcium absorption and bone calcium turnover, the role of endogenous prolactin in the regulation of calcium metabolism was investigated in the balance studies of Wistar rats between days 17 and 20 of first (P1) and fourth (P4) pregnancy and between days 12 and 15 of lactation (L). Each group was divided into 3 subgroups: one subgroup was given 0.9% NaCl (control); one was given 0.3 mg bromocriptine/100 g body weight ip twice daily for 3 days (to suppress prolactin secretion); and one was given bromocriptine and 0.25 mg prolactin/100 g body weight sc daily for 3 days. All three groups received 1 mL/100 g body weight of 1.25 mM calcium gluconate containing 2 mCi (1 Ci = 37 GBq) 45Ca daily for 3 days. Compared with the two pregnant controls, the L group had higher food consumption and higher fecal calcium excretion and lower urinary calcium excretion (% intake). Bromocriptine administration increased total calcium excretion from 59% intake to 84 and 66% intake in P1 and P4, respectively, suggesting that endogenous prolactin decreased total calcium excretion. On the other hand, exogenous prolactin had no effect on the calcium balance of P1 but increased the total calcium excretion in P4 from 57 to 66% intake. In contrast, the calcium balance of lactating rats was not altered by suppression of endogenous prolactin secretion or exogenous prolactin. Considering bone 45Ca content as representing bone Ca turnover, a lower value of bone 45Ca content indicated an accelerated bone Ca turnover. It was found that bromocriptine had no effect in P1 but decreased bone Ca turnover rate in the P4 and L groups, indicating an accelerating effect of endogenous prolactin on bone Ca turnover in the P4 and L groups. Exogenous prolactin, on the other hand, decreased bone Ca turnover rate in every group. Muscle Ca turnover was affected by bromocriptine and exogenous prolactin in the same manner as bone 45Ca contents. Interestingly, the biphasic action of prolactin was demonstrated in both calcium absorption and bone calcium turnover. It could be concluded that during pregnancy and lactation, endogenous prolactin increases food consumption, fractional calcium absorption, and bone calcium turnover, apparently to increase calcium availability for fetal development and milk calcium secretion.Key words: bone turnover, bromocriptine, calcium absorption, calcium excretion, calcium retention, prolactin.

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