Changes Produced in Postprandial Urinary Calcium Excretion by Thyroidectomy and Calcitonin Administration in Rats on Different Calcium Regimes*

Talmage, Roy V.; VanderWiel, Carole J.; Decker, Stephan; Grubb, Stephen A.

doi:10.1210/endo-105-2-459

Cited by 10 publications

(9 citation statements)

References 10 publications

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“…These experiments extended our previously reported studies [3,4] in which daily and particularly early postprandial urinary calcium changes were studied relative to the timing of calcitonin injection. For 3 consecutive weeks, two groups of TX rats and one group of TI rats were provided a calcium-free diet on Monday.…”

Section: Urine Calcium Changes Indicative Of Calcitonin-induced Storagesupporting

confidence: 69%

“…It has been proposed that calcitonin may be a digestion-related hormone functioning to conserve and store dietary calcium [1][2][3]. In an extension of these ideas, we have postulated that postprandial calcitonin secretion directs calcium obtained during intestinal absorption into the bone fluid for temporary storage [4].…”

Section: Discussionmentioning

confidence: 99%

“…Right: The same data are plotted with the time (abscissa) in log scale to test for parallelism. The two lines were nonparallel with P < 0.001 that postprandial injection of calcitonin results in an increased circulating parathyroid hormone level [3], which in turn stimulates the production of additional 1,25-vit D. The action of 1,25-vit D might persist for at least 2 days, increasing intestinal absorption of calcium. The two explanations are not mutually exclusive.…”

Section: Calcium Removed From Tibia Washed In Weak Acidmentioning

confidence: 91%

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Ultrastructural and physiological evidence for calcitonin-induced postprandial calcium storage in bones of rats

VanderWiel

Talmage

1981

Calcif Tissue Int

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Summary.The postulate tested by these experiments is that calcitonin directs a portion of the calcium absorbed from food into temporary storage at surfaces of bone. This study utilized young adult rats in which the parathyroid glands had been autotransplanted. Many rats were also thyroidectomized (TX). All were trained to a 0900 h feeding schedule with predetermined calcium content of food. Calcitonin was injected only during the first 4 h postprandially to some of the TX animals. Urine calcium was monitored and, after sacrifice, changes in the tibia were recorded. The following results were obtained: (a) In thyroid-intact (TI) rats, renal calcium excretion was reduced if the daily intake of calcium was less than 90 mg. In TX rats calcium excretion rose each day during the time of intestinal absorption of calcium. Calcitonin injection to TX rats reduced urinary calcium content on the day it was injected. However, on the following 2 days, renal calcium excretion rose to twice that of TX controls. (b) Electron micrographs of bone tissue from TI rats and TX rats injected with calcitonin showed greater pyroantimonate reaction within bone fluid than did tissue from TX controls. Similarly, when prepared by an anhydrous procedure, bone surfaces of tibia taken from rats with endogenous or exogenous calcitonin contained dense material accumulation (following a calcium-containing meal) not present in bones from TX rats. (c) When tibia shaft fragments of rats sacrificed 4 h after consuming a calcium-containing meal were washed in acidic saline, more calcium accumulated during the first 15 min in the media containing bones from TI than from TX rats. The final equilibration level between media and bone fragments was not affected by the calcitonin state of the rat. These experiments demonstrate both physiological and bone morphological differences between TI and TX rats which Send offprint requests to C. J. VanderWiel at the above address.can be negated by postprandial calcitonin injection to TX animals. They support the postulate that the secretion of calcitonin postprandially aids in the conservation and storage of ingested calcium.Key words: Calcitonin --Calcium conservation --Calcium storage --Bone ultrastructure.A definitive role for calcitonin in the normal physiology of man and other mammals has not yet been established. Even though the presence of calcitonin has been identified in plasma of all mammals studied, there is as yet no evidence that its deficiency or absence causes a detectable health problem.It has been proposed that calcitonin may be a digestion-related hormone functioning to conserve and store dietary calcium [1][2][3]. In an extension of these ideas, we have postulated that postprandial calcitonin secretion directs calcium obtained during intestinal absorption into the bone fluid for temporary storage [4]. It is suggested that a portion of the dietary calcium is retained as a calcium phosphate colloid which is prevented from crystallizing into hydroxyapatite by the presence of a mineralization inhibitor....

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Section: Urine Calcium Changes Indicative Of Calcitonin-induced Storagesupporting

confidence: 69%

Section: Discussionmentioning

confidence: 99%

Section: Calcium Removed From Tibia Washed In Weak Acidmentioning

confidence: 91%

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Ultrastructural and physiological evidence for calcitonin-induced postprandial calcium storage in bones of rats

VanderWiel

Talmage

1981

Calcif Tissue Int

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“…From studies in both man and the rat we concluded that, in thyroidectomized individuals, postprandial renal calcium excretion was primarily a reflection of the amount of calcium ingested during the immediate past meal. However, in thyroid-intact individuals, the amount of calcium in the urine was influenced by the amount of calcium consumed on the preceding day (27,28 (27 (40)(41)(42) carried out in our laboratories with 32P and 45Ca as tracers. The interpretation of the data was based on specific effects of PTH and calcitonin on plasma radioisotope specific activities.…”

mentioning

confidence: 99%

“…It is important to point out that, in rats conditioned to a specific feeding schedule, plasma calcium concentrations decrease slightly during the feeding process before an increase in plasma calcitonin can be identified (16,19). The situation is different in man, in whom it has been reported that calcitonin secretion or injection during the feeding process actually prevented rather than caused a postprandial decrease in plasma calcium concentrations (20 (27). From studies in both man and the rat we concluded that, in thyroidectomized individuals, postprandial renal calcium excretion was primarily a reflection of the amount of calcium ingested during the immediate past meal.…”

mentioning

confidence: 99%

Evidence for an important physiological role for calcitonin

Talmage

Grubb

Norimatsu³

et al. 1980

Proc. Natl. Acad. Sci. U.S.A.

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We propose that calcitonin, secreted in response to the intake of food, aids in routing calcium, obtained by intestinal absorption, into bone fluid. Here calcium is temporarily stored in combination with phosphate for return to the extracellular fluid (blood) during intervals between oral intakes of calcium. The net result is a conservation of calcium postprandially and a decrease in parathyroid hormone-induced bone destruction during subsequent fasting periods. Evidence for this postulate is provided in the following six sequential steps from the time a calcium-containing meal is consumed until that portion of calcium stored in bone fluid is utilized during fasting periods to aid in plasma calcium maintenance. This labile storage form of calcium is the first to be utilized during fasting periods. In the absence of partial disruption of this storage mechanism, rapid development of pathological bone conditions would not be expected because PTH action permits the extended utilization of bone calcium for plasma calcium control. However, augmentation of osteopenic conditions could be expected if long-term low calcium intake were accompanied by a malfunction of this calcitonin-induced system for calcium storage.

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Parathyroid Hormone and Calcitonin

Kleeman¹

1985

Contemporary Endocrinology

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Changes Produced in Postprandial Urinary Calcium Excretion by Thyroidectomy and Calcitonin Administration in Rats on Different Calcium Regimes*

Cited by 10 publications

References 10 publications

Ultrastructural and physiological evidence for calcitonin-induced postprandial calcium storage in bones of rats

Ultrastructural and physiological evidence for calcitonin-induced postprandial calcium storage in bones of rats

Evidence for an important physiological role for calcitonin

Parathyroid Hormone and Calcitonin

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