cholecalciferol and Pseudohypoparathyroidism

Topics: Cholecalciferol; Chromogranins; Diagnosis, Differential; Exons; GTP-Binding Protein alpha Subunits, Gs; Humans; Methylation; Mutation; Pseudohypoparathyroidism

Topics: Cholecalciferol; Chromogranins; Diagnosis, Differential; GTP-Binding Protein alpha Subunits, Gs; Humans; Mutation; Prognosis; Pseudohypoparathyroidism; Pseudopseudohypoparathyroidism

Topics: Cholecalciferol; Chromogranins; Diagnosis, Differential; GTP-Binding Protein alpha Subunits, Gs; Humans; Mutation; Parathyroid Hormone; Prognosis; Pseudohypoparathyroidism; Pseudopseudohypoparathyroidism

Topics: Cholecalciferol; Diagnosis, Differential; Genomic Imprinting; GTP-Binding Protein alpha Subunits, Gs; Humans; Mutation; Practice Guidelines as Topic; Pseudohypoparathyroidism

The article presents data concerning pseudohypoparathyroidism (PH TP). It is an unusual disease, which is characterized by the resistance of bones and kidney to PTH, followed by hypocalcaemia, hyperphospha-taemia, glandulary hypertrophy and hypersecretion of PTH. Patients with PTHT clinically manifest tetany seizures, soft tissue calcifications and many congenital malformations. The disease has a genetic etiology, it is connected with chromosome X and more often found in women. Clinical symptoms may be different and depend on genetic defect or its selectivity with reference to the tissues. At present we can distinguish three types of PHPT and pseudo-pseudo-HPT. The disease usually appears in the infancy. Early diagnosis and vitamin D3 or calcium treatment seem to be the most important for patient's condition. Too late treatment threatens with brain calcification followed by neurological defects and mental retardation. The long-lasting effect of PTH in bones can lead to their destruction, if bone receptors are completely sensitive.

Topics: Calcium; Cholecalciferol; Female; Humans; Infant; Male; Pseudohypoparathyroidism; Sex Distribution; Sex Factors; X Chromosome

Topics: Cholecalciferol; Diagnosis, Differential; Fibrous Dysplasia, Polyostotic; Humans; Mental Disorders; Prognosis; Pseudohypoparathyroidism

Topics: Cholecalciferol; Diagnosis, Differential; Fibrous Dysplasia, Polyostotic; Humans; Parathyroid Hormone; Pseudohypoparathyroidism; Pseudopseudohypoparathyroidism

Many advances have been made in the past several years in our understanding of the metabolism and mechanism of action of vitamin D. Recognition of the clinical implications of this knowledge continues to grow. Despite these gains, however, many questions remain unanswered. These include the role of 24,25(OH)2D3 in physiologic processes, the nature of the contribution of vitamin D metabolism to bone growth and development, the responses of other possible target tissues such as the pancreas and parathyroid gland, and the further elucidation of interactions between vitamin D metabolites and parathyroid hormone in the maintenance of calcium and phosphorus homeostasis. The next decade of research is bound to bring insight into these and other questions.

Topics: Bone and Bones; Calcium; Chemical Phenomena; Chemistry; Cholecalciferol; Humans; Hydroxycholecalciferols; Hyperparathyroidism; Intestinal Mucosa; Kidney; Mixed Function Oxygenases; Osteomalacia; Parathyroid Glands; Phosphates; Pseudohypoparathyroidism; Rickets; Vitamin D

A rapidly growing understanding of the biochemical and physiological processes that underlie the metabolism of vitamin D has provided new insights into the pathogenesis of oestomalacia. Many of the vitamin D--resistant osteomalacia syndromes can now be explained on the basis of defects in the metabolic conversion of vitamin D to the biologically active dihydroxylated metabolite 1,25(OH)2D and perhaps, in some instances, to impairement of the actions of 1,25(OH)2D on target tissues. The availability of this new information has made possible the synthesis of 1-hydroxylated forms of the vitamin for therapeutic use in states of vitamin D resistance. Although many questions regarding the pathogenesis and most effective approaches in the management of osteomalacia remain unanswered, considerable progress has been made in this direction as a result of continued research on the subject.

Topics: Bone Neoplasms; Chemical Phenomena; Chemistry; Cholecalciferol; Dihydroxycholecalciferols; Ergocalciferols; Giant Cell Tumors; Humans; Hydroxycholecalciferols; Hypoparathyroidism; Hypophosphatemia, Familial; Kidney Failure, Chronic; Metabolism, Inborn Errors; Nephrectomy; Osteomalacia; Phosphates; Pseudohypoparathyroidism; Vitamin D; Vitamin D Deficiency

Topics: Acetazolamide; Animals; Cholecalciferol; Cyclic AMP; Humans; Parathyroid Hormone; Phosphates; Pseudohypoparathyroidism

Topics: Bone and Bones; Bone Diseases; Calcium; Cholecalciferol; Chronic Kidney Disease-Mineral and Bone Disorder; Humans; Hydroxycholecalciferols; Hypoparathyroidism; Hypophosphatemia, Familial; Kidney; Liver Cirrhosis; Parathyroid Hormone; Phosphates; Protein Precursors; Pseudohypoparathyroidism; Vitamin D

Serum calcium is one of major regulators of PTH amino-terminal (N-terminal) truncation and secretion of full-length (1-84)PTH from parathyroid glands. However, the effect of active vitamin D(3) on PTH truncations remains controversial. To determine whether active vitamin D(3) accelerates the truncation of PTH, the vitamin D(3) analogue alfacalcidol was administered to patients with pseudohypoparathyroidism type Ib (PHP Ib). Both the (1-84)PTH molecule and N-terminally truncated fragments such as (7-84)PTH can be measured by commercially available two-site total PTH (T-PTH) assays. The development of whole PTH (W-PTH) assays specific for full-length (1-84)PTH has enabled us to distinguish between N-terminally truncated PTH and full-length (1-84)PTH. W-PTH/T-PTH ratios were calculated and used as an index of PTH N-terminal truncations. Both serum W-PTH and T-PTH levels were elevated in untreated PHP Ib patients. The administration of alfacalcidol reduced both the W-PTH and T-PTH levels; however, the W-PTH/T-PTH ratios were stable. Serum calcium levels were significantly and negatively correlated with both the W-PTH and T-PTH levels, but not with the W-PTH/T-PTH ratios. Thus, the administration of an active vitamin D(3) analogue did not seem to have a major effect on the rate of PTH N-terminal truncation, even though it did reduce the secretion of both full-length and truncated PTH. Possibly, active vitamin D(3) attenuates the effect of elevated calcium on PTH N-terminal truncation in PHP Ib patients.

Topics: Adult; Bone Density Conservation Agents; Calcitriol; Cholecalciferol; Down-Regulation; Female; Humans; Hydroxycholecalciferols; Male; Parathyroid Hormone; Peptide Fragments; Protein Isoforms; Pseudohypoparathyroidism; Time Factors; Young Adult

Although there have been some case reports suggesting that bone in patients with pseudohypoparathyroidism (PHP) might respond to parathyroid hormone (PTH), no information is available as to whether serum PTH concentration is related to bone metabolic markers or to bone mineral density (BMD) in PHP.. To address these relationships, by comparing intact serum PTH, bone metabolic markers and BMD in patients with PHP with those in patients with idiopathic hypoparathyroidism (IHP) and postoperative hypoparathyroidism (OHP).. Intact serum PTH, bone metabolic markers (osteocalcin, tartrate-resistant acid phosphatase, pyridinoline, deoxypyridinoline) and BMD by dual-energy X-ray absorptiometry or single-photon absorptiometry were measured in patients with PHP Ia (n=2) and PHP Ib (n=8). The results were compared with those in patients with IHP (n=5) and OHP (n=14).. All bone metabolic markers measured were present in significantly greater amounts in patients with PHP Ib than in those with IHP+OHP. The Z score (standard deviation of average BMD at each age) of the BMD of femoral neck was significantly lower in patients with PHP Ib than in those with IHP+OHP. The Z scores of BMD of lumbar spine and radius were also lower in patients with PHP Ib than in those with IHP+OHP, but the difference was not significant. Moreover, the intact serum PTH concentrations were significantly and positively related to bone metabolic marker levels in all patients, and the intact serum PTH concentrations were significantly and negatively related to BMD of lumbar spine in PHP patients.. These results suggest that PTH stimulates bone turnover in PHP Ib patients, resulting in a relatively lower BMD in PHP Ib patients than in IHP+OHP patients. The present study indicates that bones of most cases of PHP could respond to PTH.

Topics: Acid Phosphatase; Adult; Aged; Amino Acids; Biomarkers; Bone Density; Cholecalciferol; Creatinine; Cyclic AMP; Erythrocyte Membrane; Female; GTP-Binding Protein alpha Subunits, Gs; Humans; Hypoparathyroidism; Isoenzymes; Kidney; Male; Middle Aged; Osteocalcin; Parathyroid Hormone; Phosphates; Postoperative Complications; Pseudohypoparathyroidism; Tartrate-Resistant Acid Phosphatase

We report two patients with vitamin D deficiency due to unbalanced diet. The patients initially presented with severe hypocalcemia, normophosphatemia and markedly elevated serum PTH levels. Although nutritional vitamin D deficiency was suspected from their history of gastrointestinal problems and dietary restriction, we conducted Ellsworth- Howard test to exclude the possibility of pseudohypoparathyroidism (PHP). Both patients showed no incremental response of urinary phosphate excretion. However, the urinary cAMP response to exogenous PTH was different between the two. Case 1 showed a blunted response (5-fold and 1.54 micro mol/h increase) and case 2 showed a normal response (39-fold and 3.04 micro mol/h increase). According to the criteria of Ellsworth-Howard test, the data of case 1 was compatible with PHP type I, and of case 2 with PHP type II. The final diagnosis of vitamin D deficiency was established in both patients based on very low serum 25-hydroxyvitamin D levels (less than 5 ng/mL) and the effect of treatment. After calcium supplementation with or without vitamin D, their biochemical abnormalities disappeared. They maintained normocalcemia without medication after correction of their unbalanced diet. The present study indicated that patients with vitamin D deficiency occasionally showed biochemical findings suggestive of PHP and that such patients could exhibit not only PHP type II pattern of response to exogenous PTH but also of type I pattern. Thus our clinical observation suggests the complexity of PTH resistance in vitamin D deficiency and underscores the importance of diet to prevent the disorder.

Topics: Adult; Calcium, Dietary; Cholecalciferol; Cyclic AMP; Diagnosis, Differential; Diet; Female; Humans; Hypocalcemia; Parathyroid Hormone; Phosphates; Pseudohypoparathyroidism; Vitamin D; Vitamin D Deficiency

Vitamin D deficiency rickets occasionally resembles pseudohypoparathyroidism type II (PHP type II) with respect to the response to exogenous PTH in the presence of hypocalcemia. We encountered a Japanese patient with stage 2 vitamin D deficiency rickets, who had increased urinary cAMP excretion and no response of urinary phosphate or N-acetyl-beta-D-glucosaminidase excretion to exogenous PTH under normocalcemic and normophosphatemic conditions, after treatment with 1,25(OH)2 vitamin D3. This case shows that it is possible for a response mimicking that of PHP type II to occur when the serum calcidiol level is low due to causes other than hypocalcemia and secondary hyperparathyroidism. When the serum calcidiol level is low, the appropriate treatment should be cholecalciferol or ergocalciferol. However, because neither is commercially available as a useful formulation in Japan, physicians are forced to inappropriately use calcitriol or analogs.

Topics: Calcifediol; Calcitriol; Calcium; Cholecalciferol; Female; Humans; Infant; Infant Nutrition Disorders; Japan; Pseudohypoparathyroidism; Rickets; Vitamin D

The association between psoriasis and hypoparathyroidism has been reported by several authors, and it has been suggested that abnormalities in calcium homeostasis may be involved in the development or exacerbation of psoriasis. However, so far there have only been two reports of pseudohypoparathyroidism associated with psoriasis.. To describe the familial occurrence of this association for the first time.. Two siblings with psoriasis associated with pseudohypoparathyroidism were presented. The first patient was a 24-year-old white male with disseminated erythrodermic pustular psoriasis that began 2 months before admission. He had had a history of mental retardation, recurrent otitis, seizures and arthralgia from the age of 11 years onwards. He presented the characteristic phenotype of Albright osteodystrophy: short stature, obesity, round facies, broad forehead, short neck and brachydactylia. He adopted a position of flexed limbs and showed proximal muscle weakness and a positive Trousseau sign. He had clinical signs of hypocalcemia (0.69 mmol/l ionized calcium and 3.2 mg/dl total calcium), hyperphosphatemia (6.6 mg/dl), hypomagnesemia (1.0 mEq/l), hypoalbuminemia (3.1 g/dl), normal serum intact PTH levels (45.1 pg/ml), primary hypothyroidism (13.2 mU/ml TSH, and 4.7 mg/dl total T(4)), hypergonadotrophic hypogonadism (116.0 ng/ml LH, 13.2 mU/ml FSH and 325.0 ng/dl testosterone), osteoporosis, and diffuse calcifications in soft tissues and in the central nervous system. The second case was a 14-year-old white girl with a history of psoriasis vulgaris from the age of five years onwards, and antecedents of mental retardation. She presented signs of Albright osteodystrophy (short stature, round facies, obesity, short neck, brachydactylia), hypocalcemia (ionized calcium of 1.08 mmol/l and total calcium of 6.7 mg/dl) hyperphosphatemia (9.4 mg/dl), elevated serum PTH levels (223.0 pg/ml), osteoporosis, and hypergonadotrophic hypogonadism (7.0 mU/ml LH, 9.3 mU/ml FSH and undetectable estradiol levels).

Topics: Abnormalities, Multiple; Adolescent; Adult; Calcium Carbonate; Cholecalciferol; Female; Humans; Male; Nuclear Family; Pseudohypoparathyroidism; Psoriasis

Topics: Calcium; Cholecalciferol; Female; Growth Hormone; Humans; Infant, Newborn; Parathyroid Hormone; Phosphorus; Pseudohypoparathyroidism; Recovery of Function

The ratio of baseline level/maximum level of serum parathyroid hormone (PTH) is high in PTH-deficient hypoparathyroidism and it decreases after vitamin D3 treatment. There is a reversed sigmoidal relationship between the ratio and baseline serum Ca level. In this study, we further investigated the value of this ratio as a parameter of Ca-dependent changes of serum PTH in hyperparathyroid subjects. As in PTH-deficient hypoparathyroidism, the ratio in pseudohypoparathyroidism was high before vitamin D3 treatment and it decreased after 1,25(OH)2D3 treatment. The increased ratio may reflect the stimulated baseline PTH secretion from parathyroid cells perceiving the decrease in baseline extracellular Ca level. The points plotting the ratio against baseline serum Ca level were on the regression curve deduced from the data in PTH-deficient hypoparathyroidism. This result indicates that the relationship between the ratio and the baseline extracellular Ca level is unrelated to the variation in maximum secretion. The sigmoidal changes of serum PTH in patients with parathyroid adenoma were classified as follows. The first was with the upward and rightward curve shift, the second was only with the rightward curve shift, and the third was with the rightward curve shift, the increased minimum serum PTH, and the increased baseline/maximum ratio of serum PTH. These findings suggest that the decreased suppressibility of PTH secretion and the stimulated baseline secretion may develop without the increase in maximum secretion in some cases with parathyroid adenoma. In conclusion, the ratio of baseline level/maximum level of serum PTH may unfold a new aspect of secretion abnormality of parathyroid glands in several forms of parathyroid disorders.

Topics: Adolescent; Adult; Analysis of Variance; Calcium; Cholecalciferol; Female; Humans; Hyperparathyroidism; Male; Middle Aged; Parathyroid Hormone; Pseudohypoparathyroidism

The sigmoidal curves plotting serum parathyroid hormone (PTH) against serum Ca in primary hyperparathyroidism and secondary hyperparathyroidism due to renal failure deviate to the right. We previously found the leftward curve shift in PTH-deficient hypoparathyroidism. In the present study, we investigated the curve shift in pseudohypoparathyroidism (PHP) with secondary hyperparathyroidism due to target organ resistance to PTH. In renal failure the sigmoidal curves move to the left after vitamin D3 treatment. We also examined the effect of vitamin D3 on the curve shift in pseudohypoparathyroidism (PHP) and idiopathic hypoparathyroidism (IHP). Before vitamin D3 treatment, the sigmoidal curve deviated to the left in both types of hypoparathyroidism. After vitamin D3 treatment it moved to the right. These results indicate that vitamin D3 and/or extracellular Ca modify the relationship between PTH and Ca dynamics even in hypoparathyroid disorders with decreased or increased maximum serum PTH. Following vitamin D3 treatment, the point plotting baseline serum PTH against baseline serum Ca moved to the right at first in accordance with the rightward shift of the sigmoidal curve and then the point moved downward in PHP or downward in IHP. These changes suggest that vitamin D3 resets PTH secretion at a higher extracellular Ca level at first and then suppresses it in a time-dependent manner. 1, 25(OH)2D3 and/or extracellular Ca may be the determinant factors of the sigmoidal curve shift in hypoparathyroid disorders. Mechanisms other than the Ca sensing system error may contribute to the curve shift.

Topics: Adult; Calcitriol; Calcium; Cholecalciferol; Dose-Response Relationship, Drug; Female; Humans; Hypoparathyroidism; Middle Aged; Parathyroid Hormone; Pseudohypoparathyroidism; Time Factors; Vitamin D

Serum osteocalcin was measured in patients with idiopathic hypoparathyroidism or pseudohypoparathyroidism, before or during the treatment with active vitamin D3 (1,25(OH)2D3 or 1 alpha OHD3). Serum osteocalcin and plasma 1,25(OH)2D were decreased in 11 patients with idiopathic hypoparathyroidism before treatment (2.8 +/- 1.27 ng/ml, P less than 0.001 and 14.3 +/- 4.27 pg/ml, P less than 0.001, respectively). In 24 patients with idiopathic hypoparathyroidism during the treatment, serum osteocalcin and plasma 1,25(OH)2D were within the normal range (4.5 +/- 0.74 ng/ml and 25.7 +/- 5.69 pg/ml, respectively). In five patients with pseudohypoparathyroidism before treatment, plasma 1,25(OH)2D was decreased (15.6 +/- 10.6 pg/ml, P less than 0.001) but serum osteocalcin was normal (7.8 +/- 1.66 ng/ml). In nine patients with pseudohypoparathyroidism during the treatment with active vitamin D3, serum osteocalcin and plasma 1,25(OH)2D were normal (6.8 +/- 1.47 ng/ml and 27.2 +/- 6.0 pg/ml, respectively). Serum PTH in pseudohypoparathyroidism was increased before treatment (0.70 +/- 0.34 ng/ml, P less than 0.05) and was normal during the treatment (0.50 +/- 0.13 ng/ml). In idiopathic hypoparathyroidism, the active vitamin D3 increased serum osteocalcin without PTH. In pseudohypoparathyroidism, PTH may increase serum osteocalcin or modulate the effect of active vitamin D3 on serum osteocalcin.

Topics: Adult; Calcitriol; Calcium; Calcium-Binding Proteins; Cholecalciferol; Female; Humans; Hypoparathyroidism; Male; Middle Aged; Osteocalcin; Parathyroid Hormone; Phosphorus; Pseudohypoparathyroidism

Plasma concentrations of vitamin D3, 25-OH-D3, 24, 25(OH)2D3 and 1, 25(OH)2D3 were measured in patients with various diseases using the multiple assay system previously reported. In patients with hyperparathyroidism, the plasma levels of 1, 25(OH)2D3 tended to increase, while the levels of 24, 25(OH)2D3 tended to decrease in many cases. On the other hand, plasma 1, 25(OH)2D3 levels were low, while 24, 25(OH)2D3 levels were high in patients with hypoparathyroidism. No significant differences in the levels of plasma D3 derivatives among idiopathic-, postoperative- and pseudo- hypoparathyroidism were observed. In a majority of hemodialyzed patients with advanced renal failure who showed no overt bone changes on X-ray films, both the plasma 1, 25(OH)2D3 and 24, 25(OPH)2D3 levels were distributed from normal to very low. In a majority of patients with osteoporosis and hypoparathyroidism, plasma 1, 25(OH)2D3 levels rose quickly after the administration of 1 alpha-OH-D3. In hypophosphatemic vitamin D resistant rickets, however, the response to the relatively large amounts of 1 alpha-OH-D2 was poor, although the concentrations of plasma 24, 25(OH)2D3 were elevated by the 1 alpha-OH-D3 administration in most of these cases. The plasma 1, 25(OH)2D3 and 24, 25(OH)2D3 concentrations in patients with senile osteoporosis were distributed from lower to higher range than those of normal adults. There was a relatively good correlation between plasma levels of 25-OH-D3 and D3 only in cases with plasma D3 levels higher than 5 ng/ml. In addition, a hyperbolic regression curve was obtained between the plasma D3 and 25-OH-D3 ratio. These results may indicate that a possible negative feedback homeostatic mechanism exists between plasma levels of D3 and 25-OH-D3, but only with low plasma levels of D3.

Topics: Calcitriol; Cholecalciferol; Humans; Hydroxycholecalciferols; Hyperparathyroidism; Hypoparathyroidism; Kidney Diseases; Parathyroid Diseases; Pseudohypoparathyroidism

A patient treated with anticonvulsants showed hypocalcemia and hyperphosphatemia in association with increased serum parathyroid hormone, reduced serum 25-hydroxy D3, diminished response in phosphorus excretion to exogenous parathyroid hormone and normal response in cyclic AMP excretion. Oral administration of Vitamin D3 resulted in normalization of serum 25-hydroxy D3, calcium, and phosphorus. At this stage, phosphorus excretion after parathyroid hormone returned to normal. These findings suggest that the patient had pseudohypoparathyroidism type II with anti-convulsant medication as a complicating factor.

Topics: Adolescent; Anticonvulsants; Cholecalciferol; Humans; Male; Pseudohypoparathyroidism; Rickets

Endotoxin-stimulated NBT-tests were carried out in 15 patients with hypocalcemia of varying etiology and in 14 normocalcemic children free of infection. In the control group the formazan cell percentage (FCP) was 73.8 +/- 1.6% (range 63% to 83%). In 5 patients with hypoparathyroidism or pseudohypoparathyroidism the FCP before treatment was lower than normal. Vitamin D3 therapy produced a rapid increase of serum calcium but normalisation of NBT-test was only achieved after a latent period of one or more months. Patients with hypocalcemic rickets and children with an acute relapse of the nephrotic syndrome also showed abnormal results. The clinical significance of the NBT-test in hypocalcemic conditions is discussed.

Topics: Adolescent; Adult; Child; Child, Preschool; Cholecalciferol; Endotoxins; Female; Humans; Hypocalcemia; Hypoparathyroidism; Infant; Lymphocyte Activation; Male; Nephrotic Syndrome; Nitroblue Tetrazolium; Pseudohypoparathyroidism; Rickets; Tetrazolium Salts

In pseudohypoparathyroidism type I pharmacologic dosis of vitamin-D can correct hypocalcemia. Several authors who had investigated vitamin-D-metabolism in these patients, found impaired renal conversion of 25-hydroxyvitamin-D to 1,25-dihydroxy-vitamin-D. Treatment of 2 patients with pseudohypoparathyroidism type I with vitamin-D-3 and 1 alpha-Hydroxycholecalciferol consecutively resulted in a nonuniform response with regard to the normalisation of serum-calcium. This led us to the conclusion that the disturbances of vitamin-D-metabolism in pseudohypoparathyroidism type I is heterogenous.

Topics: Adolescent; Adult; Calcium; Cholecalciferol; Cyclic AMP; Female; Humans; Male; Parathyroid Hormone; Pseudohypoparathyroidism

A 37-year-old woman with typical features of pseudohypoparathyroidism (chronic tetany, paresthesia, persistent hypocalcemia, round face, short stature, short metacarpals and metatarsals, cucutaneous calcification and lack of response to exogenous and endogenous parathyroid hormone as regards urinary phosphate and cyclic AMP excretion) was treated with oral administration of 2 microgram/day of 1alphaOH-vitamin D3. Serum calcium started to rise within 3 days returning to the normal level with disappearance of symptoms referrable to hypocalcemia. Such a favorable effect of a small dose of 1alphaOH-vitamin D3 in a patient with typical hypoparathyroidism suggests an important role of disturbance of 1alpha-hydroxylation of vitamin D3 by the kidney in the pathogenesis of calcium and phosphorus abnormality in this disease. Forty-four cases of pseudohypoparathyroidism in the Japanese literature were briefly reviewed.

Topics: Administration, Oral; Adult; Calcium; Cholecalciferol; Cyclic AMP; Female; Humans; Phosphates; Pseudohypoparathyroidism

In hypoparathyroidism and pseudohypoparathyroidism, pharmacologic doses of vitamin D correct hypocalcemia, but the mechanism is unknown. In two children with hypoparathyroidism and one with pseudohypoparathyroidism we tested the hypothesis that in these conditions there is a defect in synthesis of 1 alpha,25-dihydroxyvitamin D3, the principal active metabolite of vitamin D. In both conditions, minute doses of the metabolite (0.04 to 0.08 mug per kilogram of body weight per day) quickly corrected hypocalcemia and increased intestinal calcium absorption. On the other hand, the effective dose of 25-hydroxyvitamin D3 to maintain normocalcemia was 3 to 4 mug per kilogram per day in the two conditions. Thus, the dosage ratio of 25-hydroxyvitamin D3 to 1 alpha,25-dihydroxyvitamin D3 approximated 100:1. By contrast this ratio was approximately 3:1 in two infants with vitamin D deficiency, a condition in which optimal metabolism of vitamin D would be expected. These findings suggest an impaired conversion of 25-hydroxyvitamin D to 1 alpha,25-dihydroxyvitamin D in both hypoparathyroidism and pseudohypoparathyroidism.

Topics: Administration, Oral; Adolescent; Calcium; Child; Cholecalciferol; Dihydroxycholecalciferols; Female; Humans; Hydroxycholecalciferols; Hypoparathyroidism; Injections, Intravenous; Intestinal Absorption; Male; Phosphates; Pseudohypoparathyroidism

Topics: Cholecalciferol; Dihydroxycholecalciferols; Humans; Hydroxycholecalciferols; Hydroxylation; Hypoparathyroidism; Pseudohypoparathyroidism; Vitamin D

Report on a boy aged 6-1/2 years with pseudohypoparathyroidism. This is due to a genetic lack of PTH inducible adenocyclase. Even during vitamin D treatment renal camp formation by giving PTH extract cannot be stimulated, while in this situation. PTH shows a clearly phosphaturic effect. Whether this is due to a PTH potentiated vitamin D effect is discussed. The assay of camp in urine before and after stimulation with PTH extract has proved the most certain diagnostic criterion.

Topics: Alkaline Phosphatase; Child; Cholecalciferol; Cyclic AMP; Humans; Hypocalcemia; Kidney Function Tests; Male; Phosphates; Pseudohypoparathyroidism

Topics: Adenylyl Cyclases; Anticonvulsants; Calcitonin; Calcium; Cholecalciferol; Cyclic AMP; Diagnosis, Differential; Humans; Hydroxycholecalciferols; Hypercalcemia; Hyperparathyroidism; Osteitis Deformans; Osteitis Fibrosa Cystica; Osteomalacia; Parathyroid Hormone; Pseudohypoparathyroidism; Radioimmunoassay; Thyroid Neoplasms