Plasma levels of parathyroid hormone,vitamin D,calcitonin, and calcium in association with endurance exercise

Summary Nine male marathon runners were investigated during habitual training (week 0), after 3 weeks of training break (week 3), and after 2 weeks (week 5) and 4 weeks (week 7) of retraining. Maximal oxygen uptake, body fat (BF), and plasma levels of 25(OH)D₃, 1,25(OH)₂D₃, parathyroid hormone (PTH), calcitonin (CT), albumin, and albumincorrected calcium were determined throughout weeks 0–7. The maximal oxygen uptake decreased after training break and increased during retraining (P=0.002). BF did not change significantly. Plasma 1,25(OH)₂D₃ was elevated after training break and decreased after 2 and 4 weeks of retraining [week 0: 44.0±3.7 (SEM) pg×1^-1; week 3: 52.4±6.0 pg×1^-1; week 5: 42.0±2.8 pg×1^-1; week 7: 36.9±2.3 pg×1^-1; P=0.03]. Plasma 25(OH)D₃ did not change significantly. Plasma PTH increased throughout the training break and retraining (week 0: 1.36±0.25 pmol×1^-1; week 3: 2.02±0.43 pmol×1^-1; week 5: 2.23±0.60 pmol×1^-1; week 7: 2.63±0.34 pmol×1^-1; P=0.03). Albumincorrected calcium values were transiently decreased during retraining (week 3: 2.77±0.08 mM; week 5: 2.47±0.05 mM; week 7: 2.66±0.07 mM; P=0.01). Plasma CT did not change during training break, but was transiently decreased during retraining (week 0: 9.97±0.39 pmol×1^-1; week 3: 9.91±0.37 pmol×1^-1; week 5: 8.19±0.50 pmol×1^-1; week 7: 9.02±0.45 pmol×1^-1; P=0.01). Plasma CT was correlated to albumin (r=0.46, P=0.005), albumin-corrected calcium (r=0.34, P=0.04), and maximal oxygen uptake (r=0.45, P=0.006). Plasma 1,25(OH)₂D₃ was correlated to 25(OH)D₃ (r=0.04, P=0.02), and BF (r=0.50, P=0.002). The described endurance training induced significant changes of plasma 1,25(OH)₂D₃ and PTH despite only transient changes of albumin-corrected calcium and CT.     

Glycaemic control and serum intact parathyroid hormone levels in diabetic patients on haemodialysis therapy.

BACKGROUND: Osteodystrophy is one of the long-term haemodialysis complications, and in diabetic patients, it mainly occurs as an aplastic or low-turnover type due to their low serum intact parathyroid hormone (iPTH) levels. In the present study, we investigated the role of glycaemic control to the serum iPTH levels in diabetic haemodialysis patients. METHODS: A total of 162 patients who had started haemodialysis at our hospital in the last 10 years were enrolled. Among them, 80 patients suffered from diabetic nephropathy as a primary cause of end-stage renal failure, 69 chronic glomerulonephritis, 9 polycystic kidney and 4 from other causes. We examined the serum iPTH and HbA(1c) levels of all patients at the start of haemodialysis. In 80 diabetic patients, we examined those levels both at the start of haemodialysis and 1 year later and investigated how glycaemic control affected the iPTH levels. RESULTS: The serum iPTH levels at the start of haemodialysis were significantly lower in patients with diabetes than without diabetes (P=0.032). The levels were lower in patients with poor glycaemic control than with good control (P=0.045). In the analysis of diabetic patients 1 year later, the serum iPTH levels were significantly reduced in those with poor glycaemic control (P=0.002). The multiple regression test showed that the serum HbA(1c) levels were strongly related to the serum iPTH levels (P<0.001). CONCLUSIONS: The status of glycaemic control in diabetic haemodialysis patients affects the serum iPTH levels. Good glycaemic control should be required to prevent osteodystrophy.     

The relationship between the actions of vitamin D,parathyroid hormone and calcitonin

The effect of PTH and CT upon hydroxyproline and electrolyte excretion, plasma calcium and phosphate, calcium balance, and the excretion of radiocalcium was examined in vitamin D-deficient thyroparathyroidectomized rats. The results were compared to those obtained in D-fed animals. An increase in urinary hydroxyproline, which persisted for many hours, occurred in D-deficient animals approximately 30 h after thyroparathroidectomy, but was not seen in D-fed animals. It was suppressed by high calcium infusion. Infusion of PTH or CT increased the hydroxyprolinuria even further in D-deficient animls. PTH increased hydroxyprolinuria in D-fed animals, but CT caused a significant decrease. In the D-deficient animals both PTH and CT caused a decrease in urinary calcium excretion, and an increase of the already positive calcium balance. In D-fed animals CT had similar effects, but PTH caused a significant increase in calcium excretion and a negative calcium balance. Young animals injected with⁴⁵Ca while on a D-deficient diet were studied 3 weeks later at a time when they had developed D-deficiency. When these animals were thyroparathyroidectomized and maintained on a constant glucose and electrolyte perfusion, the excretion of calcium was relatively constant and the specific activity of urnary calcium declined only slightly over a 28 h period. When PTH was given, both total and radioactive calcium excretion diminished initially, leading to a significant decrease in specific activity. The specific activity declined for the first 3 h of hormone infusion, then rose gradually and became greater than normal during the last 4 h of hormone infusion. When CT was given with PTH, total calcium excretion fell and remained below the control rate throughout the experiment. Specific activity rose markedly during the first 2 h, then fell rapidly to values below the control levels for the remainder of the experiment.

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Zusammenfassung Die Wirkung von PTH und CT auf Hydroxyprolin- und Elektrolytausscheidung, auf Plasma-Calcium und-Phosphat, Calciumbilanz und die Ausscheidung von radioaktivem Calcium wurde in Vitamin D-defizienten, thyroparathyreoidektomierten Ratten untersucht. Die Resultate wurden mit denjenigen von Ratten verglichen, welche Vitamin D erhielten. Es wurde eine Zunahme von Hydroxyprolin im Urin D-defizienter Tiere festgestellt, welche etwa 30 Std nach der Thyroparathyreoidektomie auftrat und viele Stunden anhielt. Tiere mit Vitamin D zeigten keine solche Zunahme. Hohe Calciuminfusionen unterdrückten diese Zunahme. Bei D-defizienten Tieren wurde die Hydroxyprolinurie durch Infusion von PTH oder CT noch weiter erhöht. Bei mit Vitamin D gefütterten Tieren steigerte PTH die Hydroxyprolinurie, CT jedoch bewirkte eine signifikante Abnahme. Bei den D-defizienten Tieren bewirkten PTH und CT eine Abnahme der Calciumausscheidung im Urin und eine Zunahme der bereits positiven Calciumbilanz. Bei mit Vitamin D gefütterten Tieren hatte CT ähnliche Wirkungen, aber PTH bewirkte eine signifikante Zunahme in der Calciumausscheidung und eine negative Calciumbilanz. Jungen Tieren wurde⁴⁵Ca injiziert, während sie eine D-Mangel-Diät erhielten, und sie wurden 3 Wochen später — zu einer Zeit, da sie eine D-Defizienz entwickelt hatten — untersucht. Nachdem diese Tiere thyroparathyreoidektomiert worden waren und auf einer konstanten Glucose- und Elektrolyt-Perfusion gehalten wurden, blieb die Calciumausscheidung relativ konstant und die spezifische Aktivität des Urincalciums nahm während einer Periode von 28 Std nur wenig ab. Eine PTH-Gabe verminderte anfänglich die gesamte und die radioaktive Calciumausscheidung und führte zu einer signifikanten Abnahme der spezifischen Aktivität. Die spezifische Aktivität nahm während der ersten 3 Std der Hormoninfusion ab, dann nahm sie allmählich zu und wurde während der letzten 4 Std der Hormoninfusion größer als normal. Wurde CT zusammen mit PTH gegeben, so fiel die Gesamtcalciumausscheidung und blieb während der ganzen Untersuchungsperiode unter dem Kontrollwert. Die spezifische Aktivität stieg während der ersten 2 Std stark an, fiel dann rasch auf Werte unterhalb des Kontrollniveaus und verblieb während der restlichen Untersuchung auf diesen Werten.

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Résumé L'effet de la PTH et de la CT sur l'excrétion d'hydroxyleproline et des électrolytes, le calcium et le phosphate plasmatique, l'équilibre calcique et l'excrétion du radiocalcium est étudié à l'aide de rats thyro-parathyroïdectomisés et déficients en vitamine D. Les résultats sont comparés à ceux obtenus chez des animaux recevant de la vitamine D. Une augmentation de l'hydroxleproline urinaire, qui persiste plusieurs heures, est observée chez les animaux, déficients en vitamine D, environ 30 heures après thyro-parathyroïdectomie. Cette augmentation disparait après administration élevée de calcium. L'administration de la PTH et de la CT accroit même l'hydroxyleprolinurie chez les animaux soumis à la vitamin D, mais la CT provoque une diminution nette. Chez les animaux déficients en vitamine D, la PTH et la CT diminuent la calciurie, et augmentent l'équilibre calcique, déjà positif. Chez les animaux recevant la vit. D, la CT a des effets analogues, mais la PTH provoque une augmentation nette de l'excrétion calcique, ainsi qu'un équilibre calcique négatif. De jeunes ani maux, recevant du⁴⁵Ca, alors qu'ils sont soumis à un régime pauvre en vit. D, sont examinés, trois semaines plus tard, en avitaminose D. Lorsque ces animaux sont thyro-parathyroïdectomisés et perfusés, de façon constante, en glucose et électrolytes, l'excrétion calcique est relativement constante et l'activité spécifique du calcium urinaire ne diminue que fort peu en 28 heures. Lorsqu'on administre de la PTH, l'excrétion, à la fois, du calcium total et radioactif diminue initialement en provoquant une décroissance nette de l'activité spécifique. L'activité spécifique décroit pendant les 3 premières heures d'administration d l'hormone, puis s'élève progressivement et devient plus élevée que la normale, au cours des 4 denières heures d'administration. Lorsque la CT est administrée simultanément, l'excrétion calcique totale s'abaisse et reste à des niveaux inférieurs à ceux des témoins pendant toute l'expérience. L'activité spécifique s'élève nettement pendant les 2 premières heures, puis s'abaisse rapidement à des niveaux inférieurs que ceux des témoins jusqu'à la fin de l'expérience.

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The effect of long-and short-term corticosteroids on plasma calcitonin and parathyroid hormone levels

The role of calcitonin and parathyroid hormone (PTH) in corticosteroid-induced osteoporosis is controversial. We therefore measured plasma calcitonin and PTH levels in 34 adults receiving chronic pharmacological corticosteroids for obstructive airways disease, and in controls matched for age, sex, menopause, and disease. In addition, the acute effect of a 7-day course of 15 mg prednisolone daily on fasting and calcium-stimulated calcitonin was studied in 10 normal male volunteers. There was no difference in calcitonin and PTH levels in the corticosteroid-treated patients when compared with controls. The corrected serum calcium was significantly higher in the steroid-treated patients (patients mean 2.40 (SEM 0.01) mmol/liter; controls mean 2.33 (SEM 0.01) mmol/liter; P<0.001). The short course of corticosteroids in volunteers did not alter basal or stimulated calcitonin, PTH, or calcium levels. These results suggest that neither calcitonin deficiency nor PTH excess is a feature of corticosteroid-induced osteoporosis.     

甲状旁腺素和维生素D受体基因多态对糖尿病患者骨密度的影响

目的探讨甲状旁腺素(PTH)基因多态性与中国北方汉族人糖尿病患者骨密度的关系,联合分析维生素D受体(VDR)基因和PTH基因多态性与骨密度的相关性。方法选自青岛市内分泌糖尿病医院1998年1月~2002年1月住院的糖尿病患者,运用聚合酶链反应限制性片段长度多态性(PCR-RFLP)技术检测了1型糖尿病(T1DM)组54例,2型糖尿病(T2DM)组104例,健康对照(CON)组102例,260例中国北方汉族人PTH基因多态性;采用双能X线吸收法骨密度仪(DEXA)测量骨密度。结果校正年龄和BMI后,1型糖尿病组腰椎、股骨颈骨密度低于对照组(P0.05);2型糖尿病组与对照组相比,骨密度差异无显著性(P0.05);甲状旁腺素(BSTB1位点)基因型和等位基因分布频率在1型糖尿病组、2型糖尿病组与对照组间差异无显著性(P0.05);在对照组及2型糖尿病组,BB基因型者腰椎(L2-4)和股骨颈部位骨密度显著高于Bb/bb基因型(P0.05);在1型糖尿病组,BB基因型仅腰椎L2-4部位骨密度高于Bb/bb基因型(P0.05);联合VDR基因多态(Apa I酶切位点)分析结果表明,Bbaa基因型在腰椎和股骨颈骨密度低于其他基因型(P0.05)。结论糖尿病患者PTH基因多态性(BSTB1位点)可能是预测骨量减少、骨质疏松易感性的遗传标志。联合VDR基因多态(Apa I酶切位点)有助于识别糖尿病患者发生骨质疏松的高危人群。     

原发性上尿路结石患者激素检测及其意义

目的探讨原发性上尿路结石患者体内激素的变化及其临床意义。方法测定34例男性、18例女性原发性上尿路结石患者和男女各20例健康对照者血清睾酮（Testo）、雌二醇（E2）、催乳素（PRL）、促黄体生成激素（LH）、促卵泡成熟激素（FSH）及甲状旁腺素（PTH）水平。结果男性结石组Testo、PRL、LH及PTH明显高于男性对照组（P〈0．05），E2明显低于男性对照组（P〈0．05），FSH差异无统计学意义；女性结石组PRL、PTH明显高于女性对照组（P〈0．05），其余四项指标差异无统计学意义。结论性激素对男性原发性上尿路结石患者有一定影响，而对女性原发性上尿路结石患者影响尚不明显，有待进一步研究。甲状旁腺素对男女原发性上尿路结石患者均有影响。     

Bone metabolism,parathyroid hormone,and calcitonin in paraplegia

Summary In paraplegia, osteoporosis below the neurological lesion occurs early after the spinal cord affection. The serum levels of parathyroid hormone (PTH) and calcitonin (CT), using a radioimmunoassay for the measurement of immunoreactivity, were studied in 12 paraplegic patients for 9 months following onset. Serum Ca and P levels, urinary hydroxyproline excretion, and the kinetic metabolic clearance of⁴⁵Ca have also been measured. P and immunoreactive (i) CT levels were found the highest at the beginning of the observation and progressively decreased with time. Ca and iPTH serum levels varied inversely with time, the highest level of Ca and the lowest level of iPTH being recorded at the third month following the paraplegia. Mean values of Ca, iPTH, and iCT were in the normal range throughout the study. P levels were increased during the first 3 months. Hydroxyprolinuria was also high and⁴⁵Ca kinetics showed increased values of Vt, Vo⁺, and Vu. These parameters indicate a high degree of bone turnover. The results were consistent with the assumption that PTH is not responsible for the increased resorption of bone in paraplegia. Likewise, a deficiency of CT does not seem to be responsible for this bone resorption. These endocrine modifications could be secondary to an increase in the calcium flux from bone to blood and resulting from bone destruction as attested by the increase of urinary calcium and urinary hydroxyproline excretion.     

Relationship between serum intact parathyroid hormone concentrations and bone remodeling in type I osteoporosis: Evidence that skeletal sensitivity is increased

To define the role of parathyroid gland function in the pathophysiology of bone loss in type I (postmenopausal) osteoporosis, we measured serum intact parathyroid hormone (PTH) concentration by immunoradiometric assay (IRMA) and by multisite immunochemiluminometric assay (ICMA) in 63 postmenopausal osteoporotic women (PMOp) with vertebral compression fractures and in 75 age-comparable postmenopausal normal women (PMNl). Also, tetracycline-based histomorphometric indices in cancellous bone were assessed in iliac biopsy samples from 61 PMOp and 28 PMNl women. Serum PTH concentrations by IRMA were similar in PMOp and PMNl (medians, 3.92 and 3.77 pmol/l; NS) but were significantly lower in PMOp by the more sensitive ICMA (medians, 2.82 and 3.14 pmol/l;P<0.01). By multiple linear regression analysis, serum PTH was directly related (P<0.001) to activation frequency, bone resorption rate, bone formation rate, and the calculated rate of bone loss. For each unit (pmol/l) increase in serum PTH by ICMA, activation frequency increased by 1.3%/year more (P=0.01), bone resorption rate increased by 3.9%/year more (P=0.003), and the rate of cancellous bone loss was 2.8% greater (P= 0.0003) in the PMOp women compared with the PMNl women. Concentrations of serum estradiol, but not serum estrone, had a weak opposing effect to PTH, especially for bone formation rate. These data suggest that in PMOp the bone has increased sensitivity to the biologic effects of PTH. This may represent one of the fundamental pathophysiologic defects in PMOp and, in the setting of estrogen deficiency, may explain, in part, their greater rate of bone loss.     

Low levels of 25-hydroxy vitamin D are associated with elevated parathyroid hormone in healthy adolescent females

This study aimed to investigate the relationship between 25-hydroxyvitamin D [25(OH)D)] and parathyroid hormone (PTH) levels in adolescent females residing in a northern climate. Concern regarding vitamin D status in this population is due to limited sunlight exposure in northern latitudes, decreased outdoor recreational activities, as well as decreased conversion in black girls from increased skin pigmentation. In this cross-sectional analysis, serum samples were assayed for 25(OH)D using competitive protein binding (CPB) assay and PTH with immuno-radiometric (RIA) procedures. Four hundred postmenarcheal females (12–18 years) residing in northeastern Ohio were recruited. Subjects were excluded if they had a history of bone, kidney, or liver disease, or used medications that affect bone. The primary goal was to determine serum 25(OH)D concentrations in relation to circulating PTH levels in a population of adolescent girls. The Spearman correlation test was used to compare PTH and 25(OH)D. Fit multiple split models were run to determine change in slope of the regression line when 25(OH)D and PTH were plotted. Analysis of variance was determined using modeled means with differences by race and season in the final model. Unadjusted mean serum 25(OH)D and PTH levels were 55.0±30.4 nmol/l and 39.4±20.6 ng/l, respectively. Blacks had lower 25(OH)D and higher PTH compared with non-blacks (P<0.0001), especially during the winter months. Decreasing 25(OH)D was inversely correlated with PTH (r=–0.314) (P<0.0001), and at concentrations of 25(OH)D 90 nmol/l, an increase in PTH was observed. Adolescents are at risk for decreased serum 25(OH)D concentrations, especially black girls. We found that the widely used cutoff for vitamin D deficiency is associated with increasing PTH levels and is below the inflection point for a change in the slope of the regression line. Our results support the need for further research to establish optimal vitamin D status in adolescent girls.     

Effect of calcitriol replacement on serum calcitonin and parathyroid hormone levels in CAPD patients

Calcitonin-secreting cells, ‘C cells’, have specificreceptors for calcitriol, thus the calcitriol deficiency inuraemia may affect calcitonin secretion and/or production. Theaim of the present study was to evaluate in CAPD patients theeffect of calcitriol replacement (4 weeks of oral calcitriol,0.5 ng/day) on both, basal calcitonin concentration and calcitoninresponse to calcium infusion (calcium gluconate, 3 mg/kg/h). Calcitriol replacement produced a normalization of serum calcitriollevel without a significant change in serum calcium concentration.After calcitriol replacement, basal calcitonin increased from78 ± 15 to 101 ± 13pg/ml, P<0.05. The incrementin calcitonin induced by a calcium infusion was lower after(15±4pg/ml) than before (29±4pg/ml) calcitriolreplacement. In addition, calcitriol administration induceda decrease in serum PTH level. Replacement of calcitriol in CAPD patients produced an increasein serum calcitonin concentration and a decrease in the calcitoninresponse to hypercalcaemia.     

Vitamin D, parathyroid hormone levels and bone mineral density in community-dwelling older women: The Rancho Bernardo Study

Vitamin D (25(OH)D) increases the efficiency of intestinal calcium absorption. Low levels of serum calcium stimulate the secretion of parathyroid hormone (PTH), which maintains serum calcium levels at the expense of increased bone turnover, bone loss and increased risk of fractures. We studied the association between 25(OH)D and PTH levels, and their associations with bone mineral density (BMD), bone loss, and prevalence of hip fractures in 615 community-dwelling postmenopausal aged 50–97 years. Mean level of 25(OH)D and PTH were 102.0 nmol/l±35.0 nmol/l and 49.4 ng/l±23.2 nmol/l, respectively; 49% of women were current hormone therapy users. The overall prevalence of vitamin D insufficiency (25(OH)D<50 nmol/l) was 2%, and prevalence of high PTH levels (>65 ng/l) was 17.4%. In multiple linear regression analyses hip BMD was negatively and independently associated with PTH levels ( p =0.04), and positively and independently associated with 25(OH)D levels ( p =0.03). There were only 23 women (3.7%) who experienced a hip fracture. In age-adjusted analyses there were no significant differences of 25(OH)D and PTH levels by hip fracture status. Across the entire range of values, the overall correlation between 25(OH)D and PTH was moderate ( r =–0.20). However, after the threshold vitamin D level of 120 nmol/l, all PTH values were below 65 ng/l. Further studies are necessary to identify the optimal vitamin D levels necessary to prevent secondary hyperparathyroidism.     

A 6-hour human parathyroid hormone (1–34) infusion protocol: Studies in normal and hypoparathyroid subjects

Summary Parathyroid hormone (PTH)-resistant states are usually diagnosed by the failure of an acute PTH injection to elicit a rise in urinary cAMP and phosphate or, less commonly, by the failure of repeated PTH injections to raise serum calcium. We have established a 6 hour infusion of human PTH (1–34) which identifies PTH-resistant hypoparathyroid subjects on the basis of serum 1,25-dihydroxyvitamin D (1,25(OH)₂D) and calcium responses. 1.25-Dihydroxyvitamin D levels increased by at least 58 pmol/liter and serum calcium by at least 0.1 mmol/liter in PTH-responsive hypoparathyroid subjects (n=6), whereas in pseudohypoparathyroid subjects (n=5) these levels rose by less than 22 pmol/liter and 0.06 mmol/liter respectively. The responsiveness of urinary phosphate excretion, expressed as the renal threshold phosphate concentration (TmPO₄/GFR), to PTH also clearly separated the pseudohypoparathyroid patients from the other subjects. Differences in urinary calcium responses were observed though this parameter was less reliable in the identification of individual PTH-resistant or PTH-sensitive hypoparathyroid patients. Nephrogenous cAMP did not discriminate between groups when this protocol was used. This test has the potential to facilitate and extend the classification of PTH-resistant states.     

Vitamin D status as the major factor determining the circulating levels of parathyroid hormone: a study in normal subjects

We investigated the relative contribution of the major factors regulating calcium homeostasis in determining the circulating levels of PTH. We studied 137 males and 125 females who were healthy volunteers. Circulating PTH levels were determined by three different immunoradiometric assays (IRMA). The first one (PTH Sorin, PTH S) utilizes two affinity-purified polyclonal antibodies directed against the 1–34 and 39–84 sequence of the hormone. The two other IRMA share polyclonal anti-PTH (39–84) antibodies. The first assay (PTH Whole, PTH W) utilizes a second polyclonal antibody, directed against the 1–4 amino acid sequence. The second assay (PTH Total, PTH T) utilizes a second antibody specific for the 7–34 region. Concentrations of PTH fragments lacking the initial amino acid sequence (PTH N-truncated, PTH N-t) were determined by the difference of values between PTH T and PTH W. Vitamin D was the main explicative variable almost in every multiple linear regression model, both considering the group as a whole (PTH S: R²=0.238, P<0.0001; PTH W: R²=0.08, P<0.001; PTH T: R²=0.145, P<0.0001; PTH N-t: R²=0.081, P<0.009) and when considering men and women separately. In subjects with vitamin D insufficiency (n=53) [25(OH)D<30 nmol/l], mean serum levels of parathyroid hormone were significantly higher (P<0.001) than those in subjects of similar age with normal vitamin status (n=209) with all the assays employed. This study demonstrates the central role of 25(OH)D in regulating PTH secretion in physiological conditions.     

Present and future scope of recombinant parathyroid hormone therapy in orthopaedics

Parathyroid Hormone (PTH) has a significant role in calcium metabolism. Its intermittent administration has an anabolic effect on bone mineralization. Teriparatide (PTH 1-34), a recombinant form of parathyroid hormone, is useful in the treatment of osteoporosis, fracture healing, non-union, stress fracture, augmentation of implant fixation with bone, and chondroprotection in osteoarthritis. The present review article will elaborate on the potential approved uses of recombinant PTH in orthopedics and its evolving role in the management of fracture osteosynthesis and other common challenging bone pathologies.     

Calcitonin and parathyroid hormone in newborn infants with fracture of the clavicle

Summary Determinations of serum calcium (Ca), phosphorus (P), calcitonin (CT), and parathyroid hormone (PTH) were carried out in 36 full-term newborn infants with fracture of the clavicle (CF) and in 46 normal neonates (N). At the 6th hour of life the CF neonates demonstrated lower serum Ca and higher serum CT in comparison with normal infants. In the hours following, no significant differences between the two groups for the Ca levels were found, whereas serum CT remained significantly higher in the CF newborns at the 24th, 48th, and 72nd hour of life. Significant differences between normal and CF infants in the PTH serum levels were detected only at the 48th hour, when PTH was lower in the CF newborns. The results of this investigation indicate that the fracture of the clavicle is a significant and peculiar factor in stimulating CT secretion. Serum Ca level appeared to be controlled by CT rather than auto-regulating the secretion of the hormone.     

Early effects of synthetic bovine parathyroid hormone and synthetic salmon calcitonin on urinary excretion of cyclic AMP,phosphate and calcium in man

Bovine synthetic parathyroid hormone infused intravenously in man increased both the urinary excretion of cyclic AMP and the urinary excretion of phosphate whereas a Salmon synthetic calcitonin infusion increased the urinary excretion of phosphate without change in urinary excretion of cyclic AMP. These data are consistent with the hypothesis that different renal mechanisms are involved in the response to each hormone.     

Direct in vitro evidence of the suppressive effect of cinacalcet HCl on parathyroid hormone secretion in human parathyroid cells with pathologically reduced calcium-sensing receptor levels

Clinical studies have been performed to determine the effect of cinacalcet HCl (cinacalcet), an allosteric modulator of the calcium-sensing receptor (CaR), on primary hyperparathyroidism (PHPT) and secondary hyperparathyroidism of uremia (SHPT). However, no in vitro studies on human parathyroid cells have been reported to date. In this study, the inhibitory effect of cinacalcet on PTH secretion was analyzed in primary cultured parathyroid cells obtained from patients. The investigation involved three PHPT and three SHPT patients subjected to therapeutic parathyroidectomy. Notably, all SHPT patients were resistant to intravenous vitamin D analogue therapy. Removed parathyroid tumors were used for immunohistochemistry and parathyroid cell primary culture. Immunohistochemical analyses revealed diminished expression of CaR and vitamin D receptor (VDR) in all parathyroid tumors. PTH secretion from cultured parathyroid cells of PHPT and SHPT patients was suppressed by extracellular Ca²⁺ and cinacalcet in a dose-dependent manner. Rates of suppression of PTH secretion in PHPT and SHPT by cinacalcet (1000 nmol/l) were 61% ± 21% and 61% ± 19%, respectively. Cinacalcet demonstrates significant potency in the suppression of PTH secretion in primary cultured human parathyroid cells in vitro, despite reduced levels of the target protein, CaR. Data from this in vitro analysis support the clinical application of cinacalcet in PHPT and SHPT therapy.     

Importance of serum phosphate in elderly patients with diabetes mellitus

BACKGROUND Metabolic disturbances including changes in serum calcium,magnesium or phosphate(P) influence the prevalence of type 2 diabetes mellitus(DM).We assessed the importance of serum P in elderly patients with type 2 DM vs nondiabetes mellitus(non-DM) in relation to renal function.AIM To determine the association between serum P and serum glucose or insulin resistance in diabetic and non-diabetic patients.METHODS One hundred-ten subjects with a mean age of 69.02±14.3 years were enrolled.Twenty-nine of the participants had type 2 DM(26.4%).The incidence of hypertension,smoking and receiving vitamin D(vitD) derivates were recorded.The participants were classified by both estimated glomerular filtration rate(eGFR) and albuminuria categories according to the Kidney Disease Improving Global Outcomes 2012 criteria.RESULTS We divided the patients in two groups according to the P cut-off point related to DM value.A comparison between high and low P showed that body mass index30.2±6.3 vs 28.1±4.6(P=0.04),mean glucose 63.6 vs 50.2(P=0.03),uric acid 6.7±1.6 vs 6.09±1.7(P=0.05),mean intact-parathyroid hormone 68.06 vs 47.4(P=0.001),systolic blood pressure 147.4±16.7 vs 140..2±16.1(P=0.02),mean albuminuria 63.2 vs 50.6(P=0.04) and eGFR 45.6±22.1 vs 55.4±21.5(P=0.02)were significantly different.χ~2 tests showed a significant association between high P and DM,hypertension,receiving vitD,smoking and eGFR stage(χ~2=6.3,P=0.01,χ~2=3.9,P=0.03,χ~2=6.9,P=0.009,χ~2=7.04,P=0.01 and χ~2=7.36,P=0.04,respectively).The adjusted model showed that older age,female gender and increased body mass index were significant predictors of type 2 DM when entering the covariates.CONCLUSION High serum P contributes to vascular and metabolic disturbances in elderly patients with type 2 DM and renal impairment.     

维持性血液透析患者甲状旁腺激素水平的临床分析

目的 探讨慢性肾功能衰竭维持性血液透析患者不同血浆全段甲状旁腺激素水平影响因素的差异.方法 在2006年9月至2009年8月期间于我院门诊维持性血液透析慢性肾功能衰竭患者中随机选择血浆全段甲状旁腺激素>1000 μg/L患者20例(高甲状旁腺激素组);血浆全段甲状旁腺激素<150 μg/L的患者20例(低甲状旁腺激素组).对两组患者的临床资料进行回顾性分析.结果 两组患者年龄、病死率、原发病、血肌酐、尿素氮、血浆白蛋白、血磷及钙磷乘积方面比较差异有统计学意义(P < 0.05);两组患者性别、血红蛋白、胆固醇、甘油三酯、血钙及二氧化碳结合力方面比较差异无统计学意义(P > 0.05).结论 在慢性肾功能衰竭维持性血液透析中高龄及糖尿病肾病患者低甲状旁腺激素水平的发生率明显增高;低甲状旁腺激素水平的患者病死率明显增高;高甲状旁腺激素水平患者的血肌酐、血磷及钙磷乘积水平明显高于低甲状旁腺激素水平患者,营养状况也优于后者.