Lactose and the Absorption of Calcium and Strontium

Dupuis, Y; Fournier, P.

doi:10.1016/b978-0-12-395730-6.50028-1

Cited by 20 publications

(7 citation statements)

References 27 publications

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“…A possible objection has been that there may be trace amounts of vitamin D remaining in the responsive animals. In our studies parathyroid hormone-unresponsive hypocalcemia was demonstrated and responsiveness could be restored by repeated injections of calcium chloride, or by administering dietary lactose which presumably increased calcium absorption (19). Although the mechanism whereby dietary lactose improves calcium absorption in D-deficient animals is not known, Lengemann,Wasserman,and Comar (20) have shown a rapid direct effect of lactose on 45Ca and 89Sr transport by isolated intestinal segments in rachitic rats, an effect which is not obtained by direct addition of vitamin D. In our own study, the possibility that lactose could act because of contamination with vitamin D was ruled out by assay of the lactose used in the diets.…”

Section: Discussionmentioning

confidence: 61%

Restoration of Parathyroid Responsiveness in Vitamin D—Deficient Rats by Parenteral Calcium or Dietary Lactose*

Au¹,

Raisz²

1967

J. Clin. Invest.

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Abstract. The effects of treatment with vitamin D, calcium, or lactose on the responsiveness of vitamin D-deficient rats to parathyroid hormone were compared. In the absence of vitamin D, parenteral calcium or dietary lactose administration resulted in increases in serum calcium concentration although not to the normal values obtained in animals given vitamin D. Dietary lactose also partially restored the low bone calcium content of vitamin D-deficient rats. Untreated vitamin D-deficient rats showed no significant changes in serum calcium concentration after parathyroidectomy or parathyroid extract administration. Vitamin D, lactose, and calcium all restored responsiveness to parathyroid hormone; serum calcium concentration decreased after parathyroidectomy and showed a dose-related increase in response to parathyroid extract. Hence, the unresponsiveness to parathyroid hormone in vitamin D deficiency may be due to a lack of calcium at a local site of action, presumably bone, rather than to cofactor. IntroductionThe observation that hypocalcemia can develop in vitamin D-deficient rats despite parathyroid hyperplasia has led to several studies of the relation between vitamin D and parathyroid hormone action. Harrison, Harrison, and Park (2) observed that the administration of parathyroid extract (PTE) to vitamin D-deficient, hypocalcemic rats at doses which were effective in normal animals resulted in little or no increase in serum calcium concentration. Rasmussen and coworkers (3)

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Section: Discussionmentioning

confidence: 61%

Restoration of Parathyroid Responsiveness in Vitamin D—Deficient Rats by Parenteral Calcium or Dietary Lactose*

Au¹,

Raisz²

1967

J. Clin. Invest.

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“…Of many sugars and sugar alcohols tested by Dupuis & Fournier (1963), lactose had the greatest effect. There have been various theories regarding the mechanism whereby lactose and other sugars enhance calcium absorption.…”

Section: Possible Mechanismsmentioning

confidence: 95%

“…As far as lactose is concerned the effect on calcium absorption of its presence in milk is thought to be particularly beneficial to the young growing mammal, who needs to absorb plenty of calcium to build its growing bones (Dupuis & Fournier, 1963). However, the fact that it is seemingly one of the most effective of all the carbohydrates tested in this regard should not be allowed to obscure the fact that the effect is a generic one.…”

Section: Possible Mechanismsmentioning

confidence: 98%

“…However, the fact that it is seemingly one of the most effective of all the carbohydrates tested in this regard should not be allowed to obscure the fact that the effect is a generic one. The list of carbohydrates known to act in the same way includes galactose, xylose, arabinose, mannose, sorbose, melebiose, cellobiose, raffinose, sorbitol, dulcitol, mannitol (Dupuis & Fournier, 1963), dextrin (Bergeim, 1926;Fournier, 1959), polydextrose (P. Estes, unpublished work, 1978), roasted dextrose (Fournier, 1959), and chemically modified starches (Hodgkinson et al, 1982). In other words, the effect of lactose on calcium absorption is by no means unique.…”

Section: Possible Mechanismsmentioning

confidence: 98%

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Enzootic and Epizootic Adrenal Medullary Proliferative Disease of Rats: Influence of Dietary Factors which Affect Calcium Absorption

Roe¹,

Bär

1985

Human Toxicology

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Adrenal medullary hyperplasia and neoplasia occur both enzootically and epizootically in untreated laboratory rats. The lesions are typically chromaffin-negative and are found incidentally in animals that have died from unrelated causes or have been killed at the end of long-term toxicity/ carcinogenicity tests. Urinary excretion of catecholamines is not usually increased. Environmental, particularly dietary, factors are seemingly much more important than genetic ones as determinants of the incidence of proliferative lesions. Recent observations of enhancement of adrenal medullary proliferative disease in rats by the feeding, in high dietary concentration, of certain polyols (sorbitol, mannitol, xylitol, lactitol), or of lactose, suggested that increased absorption of calcium from the gastrointestinal tract may be a risk factor. This evidence is reported and discussed in the light of other evidence linking disturbed calcium homeostasis with adrenal medullary function in the rat. In man, adrenal medullary proliferative disease is relatively rare and there is no evidence of any relation between the hypercalcaemia associated with hyperparathyroidism and increased risk of phaeochromocytoma. Adrenal medullary proliferative disease in rats is usually seen against a background of multiple endocrine neoplasia, with the pituitary gland, the pancreatic islets and the thyroid C-cells being most commonly affected in addition to the adrenal medulla. A parallel between this situation and Sipple's disease in humans has previously been suggested. We now stress the possible importance of three factors as determinants of enzootic and epizootic adrenal medullary proliferative disease in rats: excessive food intake, excessive dietary levels of calcium and phosphate and excessive intake of other food components, such as vitamin D and poorly absorbable carbohydrates, which predispose to increased calcium absorption.

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“…It has been known for many years that sugars like lactose, or polyols like sorbitol or mannitol, when added to the regimen in sufficient quantities (> 20%), significantly enhance calcium absorption [12,29,33,35]. When, in intestinal loop experiments, lactose or polyols are added to an instillate that contains relatively high calcium concentrations, calcium absorption can be doubled [13,14,21,23,34].…”

Section: Introductionmentioning

confidence: 99%

Mannitol enhances intracellular calcium diffusion in the rat ileum - a hypothesis

et al. 2000

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-The addition of 92 or 136 mM mannitol to a modified saline solution that contained 1.25 mM Ca 2+ led to a mannitol concentration-dependent increase in the amount of calcium absorbed in 1 h from 8 cm long ileal loops prepared from fasted male Sprague-Dawley rats, with body weights of 190 ± 10 g. It is argued that this mannitol-enhanced movement of calcium out of the loop cannot have utilized the paracellular pathway, inasmuch as the luminal calcium concentration of the mannitol instillate decreased during the experiment, with a negative calcium gradient between luminal and body fluids. Instead it is proposed that uncomplexed mannitol and the uncharged calcium complex of mannitol entered the ileal cells. The uncomplexed intracellular mannitol would bind additional calcium that had crossed the brush border down its gradient. The increase in total intracellular calcium will raise the effective intracellular gradient and thereby amplify intracellular calcium diffusion. This in turn increases calcium absorption. intestine / mannitol / paracellular calcium movement / transcellular calcium diffusionRésumé -Comment le mannitol augmente-t-il la diffusion transcellulaire du calcium ? Une proposition. L'addition de 92 ou 136 mmol . L -1 de mannitol à une solution saline modifiée contenant 1,25 mmol . L -1 de CaCl 2 entraîne une augmentation de la quantité de calcium absorbée en 1 h au niveau d'une anse iléale ligaturée (8 cm) chez des rats mâles Sprague Dawley (poids 190 ± 10 g) à jeun. L'augmentation de l'absorption de calcium est dépendante de la concentration de mannitol. L'entrée du calcium induite par la présence de mannitol dans la lumière ne peut avoir utilisé la voie paracellulaire car la concentration luminale du calcium diminue au cours du test et le gradient devient négatif entre lumière et milieu intérieur. Nous proposons que le complexe mannitol-Ca non chargé et le mannitol non complexé pénètrent dans la cellule iléale où ce dernier peut également lier le Reprod. Nutr. Dev. 40 (2000) 1-9 1

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Lactose and the Absorption of Calcium and Strontium

Cited by 20 publications

References 27 publications

Restoration of Parathyroid Responsiveness in Vitamin D—Deficient Rats by Parenteral Calcium or Dietary Lactose*

Restoration of Parathyroid Responsiveness in Vitamin D—Deficient Rats by Parenteral Calcium or Dietary Lactose*

Enzootic and Epizootic Adrenal Medullary Proliferative Disease of Rats: Influence of Dietary Factors which Affect Calcium Absorption

Mannitol enhances intracellular calcium diffusion in the rat ileum - a hypothesis

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