The Effect of Parathyroid extract Administration on Gastro-Intestinal Calcium Absorption in Normal Subjects

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.

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The Role of Parathyroid Hormone in the Gastro-Intestinal Absorption of Calcium

Clinical Science ◽

10.1042/cs0390089 ◽

1970 ◽

Vol 39 (1) ◽

pp. 89-94 ◽

Cited By ~ 21

Author(s):

M. R. Wills ◽

J. Wortsman ◽

C. Y. C. Pak ◽

F. C. Bartter

Keyword(s):

Parathyroid Hormone ◽

Intestinal Absorption ◽

Calcium Absorption ◽

Control Period ◽

Normal Subjects ◽

Parathyroid Extract

1. Gastrointestinal calcium absorption was studied in six normal subjects and in one patient with idiopathic hypoparathyroidism during a control period and during treatment with parathyroid extract. 2. In all subjects there was a small increase in the gastro-intestinal absorption of calcium during the administration of parathyroid extract.

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Isotopic determination of intestinal calcium absorption in normal subjects

Metabolism ◽

10.1016/0026-0495(69)90068-7 ◽

1969 ◽

Vol 18 (5) ◽

pp. 395-405 ◽

Cited By ~ 21

Author(s):

Carlos A. Mautalen ◽

Mariana L. Cabrejas ◽

Roberto J. Soto

Keyword(s):

Calcium Absorption ◽

Normal Subjects ◽

Intestinal Calcium Absorption

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Measurement of Oral Calcium Absorption from the Gut by External Isotope Counting

Journal of The Royal Naval Medical Service ◽

10.1136/jrnms-57-88 ◽

1971 ◽

Vol 57 (2) ◽

pp. 88-91

Author(s):

Murdoch A. Macleod

Keyword(s):

Vitamin D ◽

Renal Failure ◽

Calcium Metabolism ◽

Calcium Absorption ◽

Normal Subjects ◽

Intestinal Calcium Absorption ◽

Calcium Balance ◽

Oral Calcium ◽

Absorption Current ◽

Reliable Methods

AbstractAmong the factors which regulate normal gastro-intestinal calcium absorption, current thought recognises calcium intake, vitamin D and parathyroid hormone as playing an important part. It is well documented that gastro-intestinal calcium absorption is reduced in states of malabsorption, hypoparathyroidism and in patients with chronic renal failure, and raised in states of hyperparathyroidism, urolithiasis and idiopathic hypercalcuria.Difficulties inherent in classic calcium-balance techniques have prompted a search for more practical and reliable methods of measuring the degree of impairment of calcium absorption. This paper describes a study of intestinal calcium absorption in 10 normal subjects and four patients, with various disorders of calcium metabolism, using an external radio-isotope counting technique.

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