Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q92565 (GFR)
 4,179 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of hydrocortisone (HC) on the renal Pi transport in the presence and in the absence of parathyroid hormone (PTH) in the rat was examined using clearance techniques. During constant infusion of PTH in parathyroidectomized (PTX) rats, HC decreased the reabsorption of Pi from 2.84 to 2.33 mumol/min (P less than 0.001), the TmPi from 4.55 to 3.83 mumol/min (P less than 0.001), the reabs. Pi/GFR values from 0.93 to 0.74 (P less than 0.001) and the TmPi/GFR from 1.73 to 1.42 mumol/ml (P less than 0.001). In the absence of PTH, HC diminished the TmPi from 8.36 to 6.58 mumol/min (P less than 0.005) and the TmPi/GFR from 3.36 to 2.51 mumol/ml (P less than 0.001). It is concluded that the phosphaturic response of hydrocortisone may be important in the homeostasis of inorganic phosphate in the body.
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PMID:Phosphaturic response of hydrocortisone in the presence and the absence of parathyroid hormone. 732 49

Nutritional data compiled during the Growth Failure in Children with Renal Diseases Clinical Trial were analyzed to determine the relationship between the dietary intake of divalent minerals and sodium, nutritional status, and serum calcium, phosphorus, and parathyroid hormone (PTH) concentrations and blood pressure in black versus white children. One hundred eighteen patients are included in this report; 25 were black (21%) and 93 were white (79%). Although more of the blacks were male, the age distribution, midarm circumference, midarm muscle circumference, blood pressure, and serum calcium, phosphorus, and PTH concentrations were comparable in the two groups. Phosphorus intake was within the recommended daily allowance in both groups; in contrast, calcium intake was inadequate in all patients: 81% of the recommended daily allowance in whites, and 74% in blacks. Sixteen children were noted to be hypertensive during the observation period; six patients were receiving a variety of antihypertensive medications, including diuretics in two children. Linear regression analysis revealed that systolic and diastolic blood pressures were directly related to calcium and phosphorus intake in black patients. In white children, only dietary phosphorus intake and diastolic blood pressure were directly related. There was no relationship between sodium intake or GFR and blood pressure in the white or black children. PTH levels were directly correlated with systolic and diastolic blood pressure in all children. The correlations between PTH and blood pressure were stronger in white versus black patients.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The relationship between calcium, phosphorus, and sodium intake, race, and blood pressure in children with renal insufficiency: a report of the Growth Failure in Children with Renal Diseases (GFRD) Study. 757 65

Persistent hyperparathyroidism and impaired tubular reabsorption of phosphate (P) are common after kidney transplantation. In order to assess the suppressibility of these abnormalities, we studied the effects of a single oral calcium (Ca) load (1 g) in 7 healthy subjects (HS) and in 14 normocalcemic long-term renal transplant recipients with good renal function (RT). In HS and RT, serum and urinary Ca were similar at baseline, and increased (p < 0.001) to the same extent after Ca ingestion. Serum parathyroid hormone (PTH) and nephrogenic cAMP (NcAMP) levels were higher at baseline in RT than HS (mean +/- SEM; respectively, PTH 7.8 +/- 0.8 vs. 3.5 +/- 0.6 pmol/l, p < 0.001, and NcAMP 24.8 +/- 2.3 vs. 13.9 +/- 2.3 nmol/l GFR, p < 0.01). After Ca, PTH (p < 0.001) and NcAMP (p < 0.01) decreased markedly in both RT and HS. Maximal changes in PTH and NcAMP were larger in RT than HS (PTH - 3.3 +/- 0.4 vs. -2.1 +/- 0.03 pmol/l, p < 0.01, and NcAMP -18.2 +/- 3.3 vs. -8.1 +/- 2.6 nmol/l GFR, p < 0.05). Although PTH levels remained significantly higher in RT than HS from baseline to the end of the study (p < 0.001), PTH decreased to the normal range in RT after Ca load. Moreover, NcAMP reached similar values in RT and HS after Ca (16.0 +/- 3.3 vs. 13.2 +/- 2.8 nmol/l GFR at the end of the survey, NS).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Acute oral calcium load decreases parathyroid secretion and suppresses tubular phosphate loss in long-term renal transplant recipients. 761 49

It is unclear whether cyclosporin A (CsA) alters the synthesis of 1,25-dihydroxyvitamin D3 [1,25(OH)2D] by the normal human kidney. Serial changes in 1,25(OH)2D, parathyroid hormone (PTH), GFR and renal blood flow were compared in 14 patients with psoriasis who were being treated with less than 5 mg/kg/day of cyclosporin for 3 months. GFR fell significantly although there were no significant changes in serum 1,25(OH)2D, 25-hydroxyvitamin D or PTH. Absolute values for GFR and PTH were negatively correlated (rP = -0.54; p < 0.001) as were the changes in GFR and PTH observed during CsA therapy (rP = -0.73; p < 0.05). The significant fall in serum magnesium was not significantly correlated with changes in PTH. The close relationship between changes in GFR and PTH suggests that a reduction of GFR within the normal range is enough to stimulate production of PTH. CsA does not appear to stimulate the synthesis of 1,25(OH)2D3 in man.
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PMID:Interrelationship between serum concentrations of 1,25-dihydroxyvitamin D, parathyroid hormone and renal haemodynamics after low dose cyclosporin. 770 Feb 11

The mechanisms underlying the effects of recombinant human growth hormone (rhGH) on vitamin D, mineral, and bone metabolism are not known. We examined whether these effects are mediated by parathyroid hormone (PTH) by measuring renal phosphorus (P) and calcium (Ca) handling, serum calcitriol, and markers of bone turnover for 24 h before and 72 h after an infusion of hPTH(1-34) in eight healthy postmenopausal women at baseline and following short-term (1 week) and sustained (5 weeks) rhGH treatment. On short-term rhGH, serum phosphorus and basal TmP/GFR were unaffected, but the fall in TmP/GFR after hPTH infusion was exaggerated (integrated response: -99.2 +/- 22.3 versus -144.1 +/- 15.0 minute-mg/dl, P = 0.0021). Basal calcitriol levels rose from 115 +/- 17 to 163 +/- 16 pM (P = 0.0002), but the increase in calcitriol following hPTH infusion was unaffected by short-term rhGH. The basal Ca excretion index (CEI) rose from 0.054 +/- 0.005 to 0.073 +/- 0.007 mM (P = 0.0095), but markers of bone turnover were unaffected. With sustained rhGH treatment, serum P (1.47 +/- 0.05 mM), basal TmP/GFR (4.29 +/- 0.24 mg/dl), and basal CEI (0.067 +/- 0.005 mM) were elevated compared with control values, and the PTH-induced lowering of TmP/GFR was again enhanced (-158.7 +/- 22.8 minute-mg/dl, P = 0.0021). Basal calcitriol concentrations returned to control levels (108 +/- 10 pM), but the calcitriol response to hPTH remained unchanged. Markers of bone remodeling were elevated with sustained rhGH treatment.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interactions of growth hormone and parathyroid hormone in renal phosphate, calcium, and calcitriol metabolism and bone remodeling in postmenopausal women. 786 23

Primary hyperparathyroidism is a rare disease in children and is characterized by conspicuous skeletal and renal changes. A 12 year old male patient presented with symptoms of polydipsia, polyuria, general weakness, nausea, and vomiting which had begun 3 months earlier, and showed typical laboratory findings of primary hyperparathyroidism. Confirmatory diagnosis was made by elevated parathyroid hormone concentration in serum, technetium-thallium subtraction scan imaging method and histopathologic finding of chief cell hyperplasia. The laboratory findings revealed elevated levels of BUN, creatinine and decreased GFR. Kidney biopsy showed typical calcium deposits in tubules with marked tubulointerstitial infiltration. After subtotal parathyroidectomy, clinical findings improved remarkably.
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PMID:A case of primary hyperparathyroidism with hypercalcemic nephropathy in children. 799 97

During the development of vertebrates, the extracellular concentration of inorganic phosphate (Pi) is maintained at a higher level than during adult life. This elevation is probably essential for both cellular growth and mineralization of the skeleton. A high tubular Pi transport capacity (maxTRPi/GFR) and a high plasma level of 1,25-dihydroxyvitamin D3 are considered to play a major role in the high Pi retention observed during growth. Experimental studies have shown that the high maxTRPi/GFR observed in growing young compared with adult individuals is not associated with differences in other renal functions, suggesting the existence of a selective homeostatic process. Growth hormone (GH) had no direct effect on renal Pi reabsorption, indicating that GH stimulation of renal Pi transport in various physiological and pathophysiological conditions is induced by insulin-like growth factor-1 (IGF-1), the mediator of the anabolic effects of GH. In hypophysectomized rats, administration of IGF-1 mimicked the stimulatory effects of GH on maxTRPi per milliliter glomerular filtrate and on plasma 1,25-dihydroxyvitamin D3. As for GH, the change in maxTRPi per milliliter glomerular filtrate induced by IGF-1 was mediated by a parathyroid hormone-independent mechanism and was selectively expressed at the level of the luminal membrane of proximal tubules. These observations are evidence that IGF-1 mediates the effect of GH on the renal handling of Pi and production of 1,25-dihydroxyvitamin D3 and might play a significant role in the control of Pi metabolism during growth. Recent observations suggest that other growth factors might be involved in the regulation of tubular Pi transport.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Growth factors and renal regulation of phosphate transport. 813 Jan 13

This study was carried out in order to determine interrelationships of age and sex on parameters within the parathyroid endocrine system in healthy men and women. One hundred and fifteen normal subjects (70 females and 45 males) subdivided into three groups aged 25-35, 45-55 and 65-75 years were studied. Female subjects aged between 45 and 55 were further subdivided into two age-matched groups in relation to gonadal functional status. Serum intact parathyroid hormone (PTH) concentrations were measured using a two-site immunoradiometric assay. We found that there was a significant decrease of serum ionized calcium with ageing only in men (r = -0.666, P < 0.001) and a significant increase of serum PTH with age in both men (r = 0.488, P < 0.001) and women (r = 0.279, P < 0.019). A significant inverse correlation was found between serum ionized calcium and PTH in male subjects (r = -0.661, P < 0.001) and in fertile females (r = -0.353, P < 0.037) but not in postmenopausal women or in the entire female population. Furthermore, we found a significant decline of serum phosphate (r = -0.484, P < 0.001) and TmP/GFR (r = -0.492, P < 0.001) with advancing age in men, but not in women. We believe that the decrease of serum ionized calcium, as a likely consequence of the physiological reduction of intestinal calcium absorption, is the pivotal factor responsible for the increased PTH levels we observed with advancing age. The phenomenon is clear in men and in premenopausal women, but is masked in the female sex at menopause by the effects of a shortage of oestrogen on the calcium-phosphorus metabolism. These may also be responsible for the differences observed between the two sexes as far as phosphate metabolism is concerned. In conclusion, this study has, for the first time, taken relationships between serum ionized calcium and PTH, over a wide age range, into consideration. The results obtained show a marked difference of serum ionized calcium values between sexes with ageing, while serum parathyroid hormone levels increase in both men and women. Important differences also exist, as far as phosphate metabolism is concerned, between males and females.
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PMID:Serum ionized calcium, parathyroid hormone and related variables: effect of age and sex. 814 63

Twenty-four children with idiopathic absorptive hypercalciuria (IAH) and a control group (CG) of 11 healthy children were studied. Plasma 1,25-hydroxyvitamin D3 (calcitriol), parathyroid hormone (PTH), calcium (Ca) and phosphate (P) levels were measured during dietary manipulation. The three diets analyzed were: (A) calcium-restrictive diet (400 mg/1.73 m2/day) for 7 days; (B) supplemented diet (1,000 mg/1.73 m2/day) for 3 days; (C) supplemented diet continued for 15 days. The IAH group had higher levels of serum calcitriol than the control group for all three diets. Serum calcitriol levels in the IAH group decreased in diet B compared to diet A, and returned to levels observed with diet A during diet C. Serum Ca, P and plasma PTH levels did not vary throughout the study in either group. In IAH, two subgroups were observed. In one, serum calcitriol levels were elevated and in the other, serum calcitriol levels were not different from the controls. This second group had a lower P and maximum rate of tubular reabsorption of phosphate per 100 ml of glomerular filtrate than the IAH group with elevated serum calcitriol levels and the control group. These results suggest that IAH in children may be related both to increased serum calcitriol levels and to an altered Tmp/GFR.
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PMID:Influence of calcium intake on calcitriol levels in idiopathic hypercalciuria in children. 841 88

Postoperative phosphate dynamics were studied in 30 patients who underwent radical surgery for thoracic esophageal cancer and who were postoperatively nourished by total parenteral nutrition. There was a significant fall in the serum phosphate level on the 2nd and 3rd postoperative days in all patients. Postoperative hypophosphatemia was due to an increase in urinary phosphate excretion which was indicated by the fall in TRP% and TmPO4/GFR. A highly significant positive correlation was observed between the increase in urinary phosphate loss and the enhanced secretion of parathyroid hormone which was possibly triggered by surgical stress, a decrease in the serum level of calcium, the action of phosphate buffer or diuretics. All the patients except for those with postoperative pulmonary complications responded to the drop in serum phosphate by renal conservation of phosphate. A slight decrease in the serum level of phosphate was also found on the 6th postoperative day in most patients who were receiving parenteral hyperalimentation. The second fall in phosphate was due to transcellular shifts of phosphate. It is concluded that patients with postoperative pulmonary complications develop severe hypophosphatemia which should be prevented by replacement therapy with phosphate in the immediate postoperative period.
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PMID:[Postoperative hypophosphatemia in patients with cancer of the thoracic esophagus]. 846 25


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