The Measurement of Intestinal Calcium Absorption by External Radioisotope Counting: Application to Study of Nephrolithiasis

1970 ◽  
Vol 39 (1) ◽  
pp. 95-106 ◽  
Author(s):  
M. R. Wills ◽  
E. Zisman ◽  
J. Wortsman ◽  
R. G. Evens ◽  
C. Y. C. Pak ◽  
...  
Keyword(s):  
Calcium Absorption ◽  
Scintillation Counter ◽  
Renal Stones ◽  
Normal Subjects ◽  
Total Radioactivity ◽  
Urinary Calcium ◽  
Intestinal Calcium Absorption ◽  
Absolute Amount ◽  
Calcium Load ◽  
Fractional Calcium Absorption

1. Gastro-intestinal absorption of calcium was studied in man by the measurement of forearm radioactivity in a large-volume liquid scintillation counter following separate oral and intravenous doses of 47CaCl2. From the ratio of the percentages of total radioactivity appearing in the forearm following these separate determinations the fractional absorption of calcium was estimated. 2. Changes of forearm radioactivity with time following the administration of this isotope were studied; evidence is presented that the radioactivity in the forearm at 4 h after administration of the isotope gives a valid assessment of fractional calcium absorption. 3. Fractional calcium absorption determined by this technique correlated well with the net calcium absorption as determined from stool radioactivity after oral administration of isotope. 4. In normal subjects it was shown that fractional calcium absorption measured by this technique varies inversely with the stable calcium load and that the absolute amount of calcium absorbed from given loads increases with the size of the load in the range 20–1000 mg calcium. 5. Gastro-intestinal calcium absorption was measured at various oral calcium loads in a group of fifteen patients with recurrent calcium-containing renal stones. All the patients were normocalcaemic; some had hypercalciuria. In the patients with hypercalciuria, calcium absorption, fractional and absolute, was significantly increased at all calcium loads as compared to that of patients with normal urinary calcium. 6. It is concluded that hyperabsorption of calcium from the gastro-intestinal tract plays a crucial role in the aetiology of hypercalciuria, probably by causing an increase in the renal filtered calcium load.

Critical appraisal of oral calcium load test for indirect assessment of intestinal calcium absorption

Urology ◽  
1979 ◽  
Vol 14 (3) ◽  
pp. 251-255 ◽  
Author(s):  
Kashayar Sakhaee ◽  
Roy Peterson ◽  
Cheryl Northcutt ◽  
Charles Y.C. Pak
Keyword(s):  
Critical Appraisal ◽  
Calcium Absorption ◽  
Intestinal Calcium Absorption ◽  
Load Test ◽  
Oral Calcium ◽  
Indirect Assessment ◽  
Calcium Load

scholarly journals Intestinal Calcium Absorption and Serum Vitamin D Metabolites in Normal Subjects and Osteoporotic Patients

1979 ◽  
Vol 64 (3) ◽  
pp. 729-736 ◽  
Author(s):  
J. C. Gallagher ◽  
B. Lawrence Riggs ◽  
John Eisman ◽  
Alan Hamstra ◽  
Sara B. Arnaud ◽  
...  
Keyword(s):  
Vitamin D ◽  
Calcium Absorption ◽  
Serum Vitamin ◽  
Normal Subjects ◽  
Intestinal Calcium Absorption ◽  
Vitamin D Metabolites ◽  
Serum Vitamin D

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.

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.

Calcium metabolism in paravertebral ligamentous ossification

1985 ◽  
Vol 109 (3) ◽  
pp. 428-432 ◽  
Author(s):  
Yoh Takuwa ◽  
Toshio Matsumoto ◽  
Takahide Kurokawa ◽  
Masashi Iizuka ◽  
Yuichi Hoshino ◽  
...  
Keyword(s):  
Calcium Absorption ◽  
Mineral Metabolism ◽  
Normal Serum ◽  
Intestinal Calcium Absorption ◽  
Calcium Excretion ◽  
Baseline Serum ◽  
Oral Calcium ◽  
Significant Difference ◽  
Calcium Load ◽  
Serum Inorganic Phosphate

Abstract. Twenty-eight patients with paravertebral ligamentous ossification (PVLO) and 11 control subjects were studied in an attempt to examine possible involvement of disturbances in mineral metabolism in the development of PVLO. No significant difference in baseline serum calcium and fasting urinary calcium excretion was found between patients with PVLO and controls. Patients with PVLO showed lower serum inorganic phosphate (Pi) and tubular reabsorptive capacity for Pi (TmP/GFR) than controls. Basal nephrogenous cyclic 3',5'-AMP (NcAMP) was elevated in some patients with PVLO. A significant inverse relationship was found between basal TmP/GFR and NcAMP in patients with PVLO (r = −0.50; P < 0.01). Compared with controls, patients with PVLO had significantly lower calciuric responses to an oral calcium load (P < 0.05), suggesting decreased intestinal calcium absorption. Furthermore, a significant inverse correlation was found between basal NcAMP and the calciuric response in patients with PVLO (r = −0.42; P < 0.05). Serum 25-hydroxyvitamin D (25OHD) and 1,25-dihydroxyvitamin D (1,25(OH)2D) levels were not significantly different between the two groups. The size of ossified areas in paravertebral ligaments estimated from spinal radiograms inversely correlated with the calciuric response to the oral calcium load (r = −0.50; P < 0.01). These data demonstrate that the development of PVLO is associated with decreased intestinal calcium absorption in the face of normal serum 1,25(OH)2D level. Thus, together with previous observations showing a high incidence of PVLO in patients with hypoparathyroidism or familial hypophosphataemic rickets/osteo-malacia, the present results suggest that the defect in the action of 1,25(OH)2D may underlie the development of PVLO.

Isotopic determination of intestinal calcium absorption in normal subjects

Metabolism ◽  
1969 ◽  
Vol 18 (5) ◽  
pp. 395-405 ◽  
Author(s):  
Carlos A. Mautalen ◽  
Mariana L. Cabrejas ◽  
Roberto J. Soto
Keyword(s):  
Calcium Absorption ◽  
Normal Subjects ◽  
Intestinal Calcium Absorption

scholarly journals Does the response of bone mass to calcium supplements depend on calcium absorption efficiency?

2004 ◽  
pp. 759-763 ◽  
Author(s):  
E Smith ◽  
AG Need ◽  
CG Schultz ◽  
M Horowitz
Keyword(s):  
Calcium Absorption ◽  
Absorption Efficiency ◽  
Urinary Calcium ◽  
University Hospital ◽  
Calcium Supplements ◽  
Dihydroxyvitamin D ◽  
Ionised Calcium ◽  
Calcium Load ◽  
The Mean ◽  
Single Blood Sample

OBJECTIVE: Calcium supplements can reduce bone resorption and slow bone loss after the menopause, but these effects may be limited by poor intestinal absorption. Since the increase in blood ionised calcium and decrease in serum parathyroid hormone after a calcium load are diminished in patients with poor calcium absorption, we aimed to see whether the response of bone mineral content (BMC) to calcium is related to initial calcium absorption. DESIGN: We retrospectively examined the changes in forearm BMC in 164 patients (139 women and 25 men) receiving calcium therapy alone for low bone density in a university hospital. METHODS:BMC was measured in a Molsgaard single energy absorptiometer and calcium absorption in a single blood sample 1 h after a dose of 5 muCi (45)Ca in 20 mg calcium carrier. Results were analysed by simple and multiple regression analysis. RESULTS: Mean forearm BMC did not change significantly over the mean 43 (s.D., 33) months of treatment (1.023 (0.247) to 1.017 (0.246) g/cm). The annual percentage of change was positively related to both body weight (r=0.180; P=0.020) and radiocalcium absorption (r=0.185; P=0.017). Multiple linear regression confirmed that both variables contributed to the change in BMC (P=0.023 and 0.019 respectively). The mean annual percentage of change in BMC on calcium therapy was not related to age, initial BMC, serum 1,25-dihydroxyvitamin D or fasting urinary calcium/creatinine ratio. CONCLUSIONS: These results support our earlier studies which suggest that poor calcium absorption limits the response of bone to calcium supplements.

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