Calcitonin Secretion

Deftos, Leonard J.

doi:10.1016/b978-0-12-135302-5.50014-6

Cited by 3 publications

(2 citation statements)

References 197 publications

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“…Their results might indi¬ cate an intrinsic pathophysiologic difference be¬ tween tumour cells and normal cells. Our findings is not necessarily consistent with the preliminary report by Deftos et al (1978), who demonstrated that a progressive increase in serum CT levels occurred during magnesium administration.…”

Section: Resultscontrasting

confidence: 64%

“…However, the effect of hypermagnesaemia on serum CT has not been extensively studied in normal human subjects. Some investi¬ gators demonstrated no significant change of se¬ rum immunoreactive CT (iCT) levels during mag¬ nesium infusion in pre-eclamptic women (Cruikshank et al 1979), whereas others found a marked increased level of serum iCT during magnesium administration (Deftos et al 1978). On the other hand, Anast et al (1975) reported that magne¬ sium administration caused a decrease in circula¬ ting iCT in patients with thyroid medullary car¬ cinoma.…”

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confidence: 98%

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The effect of hypermagnesaemia on serum immunoreactive calcitonin levels in normal human subjects

Suzuki

Kôno²,

Onishi³

et al. 1987

Acta Endocrinologica

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The effect of hypermagnesaemia on serum levels of immunoreactive calcitonin was studied in normal human subjects. After iv administration of magnesium sulphate over 120 min, the mean (\m=+-\sem) serum magnesium concentration rose from the baseline level of 0.9 \m=+-\0.1 to 2.6 \m=+-\0.3 mmol/l (P < 0.01), and thereafter remained higher than the baseline level. The magnesium infusion caused a significant increase in serum immunoreactive calcitonin levels (P < 0.01). The rise in serum magnesium concentration was accompanied by a significant decrease in the concentrations of corrected serum calcium and whole blood ionized calcium (P < 0.01, P < 0.01, respectively). Our results suggest that hypermagnesaemia causes an increase in serum immunoreactive calcitonin levels in normal human subjects despite a decrease in the concentrations of corrected serum calcium and whole blood ionized calcium.Although calcium is the principal regulator of the thyroid C-cell function, magnesium has also been observed to have an important role. All reports of in vitro and in vivo animal studies indicate that magnesium, like calcium, stimulates the release of calcitonin (CT) from the thyroid gland (Radde et al. 1969; Bell 1970; Care et al. 1971; Littledike & Arnaud 1971). However, the effect of hypermagnesaemia on serum CT has not been extensively studied in normal human subjects. Some investi¬ gators demonstrated no significant change of se¬ rum immunoreactive CT (iCT) levels during mag¬ nesium infusion in pre-eclamptic women (Cruikshank et al. 1979), whereas others found a marked increased level of serum iCT during magnesium administration (Deftos et al. 1978). On the other hand, Anast et al. (1975) reported that magne¬ sium administration caused a decrease in circula¬ ting iCT in patients with thyroid medullary car¬ cinoma. To study the effect of hypermagnesaemia on serum iCT levels in normal human subjects, we analysed changes in serum iCT levels, and con¬ centrations of corrected serum calcium and whole blood ionized calcium during and after iv admini¬ stration of magnesium sulphate. Subjects and MethodsSeven healthy men ranging in age from 20 to 34 years (mean 26 years) participated in the study. Informed consent was obtained from each subject. Our investiga¬ tion was conducted in accordance with the principles of the Declaration of Helsinki II and was approved by our institutional review board. While the subjects were

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Section: Resultscontrasting

confidence: 64%

mentioning

confidence: 98%

The effect of hypermagnesaemia on serum immunoreactive calcitonin levels in normal human subjects

Suzuki

Kôno²,

Onishi³

et al. 1987

Acta Endocrinologica

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Increased plasma calcitonin levels in young spontaneously hypertensive rats: role in disturbed phosphate homeostasis

et al. 1987

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In young spontaneously hypertensive rats (SHR) and in normotensive Wistar-Kyoto controls (WKY) several parameters of phosphate and calcium homeostasis were determined. At 6 and 8 weeks, blood analysis revealed a significant hypophosphatemia (p less than 0.001) in SHR and twice as high plasma calcitonin levels in SHR than in WKY controls. At 8 weeks, 1,25-dihydroxycholecalciferol concentration was 20% higher in SHR (p less than 0.02) while 25-hydroxycholecalciferol was unaltered (p greater than 0.51). In addition total immunoreactive PTH, iPTH, was slightly increased (p less than 0.07) but intact PTH (1-84) (p greater than 0.90) was not significantly different from age matched WKY controls. Also at 8 weeks, a slightly reduced serum ionized Ca2+ concentration (p less than 0.001) with no change in total serum calcium was found in SHR (p greater than 0.39). Balance studies at 6 and 8 weeks of age revealed no significantly different balances for phosphate (F = 2.5, p greater than 0.10) and for calcium (F = 2.6, p greater than 0.09), although a tendency for slightly more positive balances existed in SHR when compared to WKY. However, SHR excreted significantly less phosphate in the urine than WKY control (F = 0.2, p less than 0.0009). Bone analysis was performed on femora of SHR and WKY of 6 weeks of age. Femora were significantly shorter in SHR (20.54 +/- 0.35 vs. 21.50 +/- 0.05 mm in WKY), whereas bone dry weight (127 +/- 6 vs. 107 +/- 2 mg).(ABSTRACT TRUNCATED AT 250 WORDS)

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Effect of estrogens and phosphorus depletion on plasma calcitonin in the rat

1983

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Summary.To investigate interactions between estrogens and calcitonin (CT), we have studied the effect of oophorectomy and estrogen replacement on plasma CT in female rats in response to an acute intravenous calcium stimulus and to hypercalcemia induced by dietary phosphorus deprivation.Plasma CT 5 min after an intravenous calcium stimulus (10 mg Ca/kg) was 176 • 11 pg/ml (mean • SEM) in rats subjected to oophorectomy compared with 244 • 15 pg/ml in sham-operated control rats (P < .001). Administration of estradiol benzoate (10/xg/kg/day) for 14 days restored the stimulated plasma CT concentration to 221 • 15 pg/ml (P < .02 compared with oophorectomy). On regression of plasma CT against calcium, including both basal and stimulated values, the slopes (• standard error of estimate) were 23.7 • 5.0 pg CT/mg Ca for controls, 16.1 • 4.0 after oophorectomy, and 26.0 --+ 3.2 after estrogens. Rats placed on a low phosphorus diet demonstrated a fall in plasma phosphorus, a rise in plasma calcium, a decrease in plasma parathyroid hormone (PTH), and a rise in plasma CT after phosphorus depletion. In male rats, plasma CT was maximal on day 2 of phosphorus depletion (109 • 15 pg/ ml vs 47 • 4 pg/ml for controls, P < .001), and continued phosphorus deprivation was associated with a significantly decreased plasma CT response to an intravenous calcium stimulus (mean 167 • 9 vs 284 • 21 pg/ml, P < .001). There was an inconsistent effect of oophorectomy in lowering CT levels on day 2 of phosphorus depletion and no effect on day 15 (94 ---19 pg/ml vs 82 ___ 9 pg/ml). We conclude that estrogens increase the plasma CT response to an acute intravenous calcium stimulus. We examined the effect of phosphorus depletion on CT as a model for endogenous hypercalcemia. Phosphorus deprivation was found to be a potent stimulus to plasma CT, but we could not consistently demonstrate an effect of endogenous estrogens on plasma CT under these conditions (estrogen-hypophosphatemia-calcitonin).Keywords: Estradiol --Hypercalcemia --Calcitonin --Oopherectomy.Estrogen and calcitonin (CT) are known to modulate bone metabolism. Estrogens antagonize the effects of parathyroid hormone in the rat [1] and in man [2-4]; CT causes hypocalcemia by inhibition of bone resorption [5,6]. Endogenous CT in the rat is effective also in controlling plasma calcium in the face of dietary calcium intake [7]. The possibility of interactions between estrogens and CT is suggested by the observation that plasma CT is greater in female than in male rats [8,9]. Therefore, we felt it was of interest to study the effect of estrogens on CT in this species. In this paper, we report our studies of the effect of oophorectomy and estradiol on plasma CT response to acute and chronically induced hypercalcemia. Materials and MethodsSprague-Dawley rats (approximately 200 g) were alternately assigned to groups by ascending weight. Bilateral gonadectomies or sham procedures were performed under pentobarital (30-40 mg/kg) and ketamine (50 mg/kg) anesthesia. Experiments were

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Calcitonin Secretion

Cited by 3 publications

References 197 publications

The effect of hypermagnesaemia on serum immunoreactive calcitonin levels in normal human subjects

The effect of hypermagnesaemia on serum immunoreactive calcitonin levels in normal human subjects

Increased plasma calcitonin levels in young spontaneously hypertensive rats: role in disturbed phosphate homeostasis

Effect of estrogens and phosphorus depletion on plasma calcitonin in the rat

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