Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

50 patients with autonomous growth hormone excess (48 with adult acromegaly and 2 with gigantism) were studied between 1966 to 1986 (2.38 pts/year). Characteristic clinical presentation, an increase in growth hormone (GH) uninhibited by glucose, and/or hyperphosphemia and hyperhydroxiprolinuria were present in all patients. No cases of hypercalcemia were recorded. Phosphemia was increased in 55.8%, alkaline phosphatases in 61.7%, calciuria in 26.9% and hydroxyprolinuria in 74.2% of the patients. Basal GH was over 5 ng/ml (89.9 DS +/- 170.9) in 42 pts, and in 37 was not suppressed after glucose administration, 38% had an increased (paradoxical response) and 62% a flat response (less than 50% change of basal values). TRH test was performed in 14 patients, 8 presented an increase in GH titer. Hyperprolactinemia was seen in 4 of 12 patients in whom this hormone was measured. The size of the sella turcica was increased in 93%, and although the larger sellar size correlated to higher levels of GH, correlation was not significant. 20% of the pts had rheumatological disease, 14% goiter, 12% cardiac disease, 26.5% had diastolic hypertension and 4% renal lithiasis (hypercalciuric pts). 38% had hyperglycemia with a diabetic glucose tolerance test and 18% had non-diabetic abnormal glucose tolerance test.
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PMID:[Active acromegaly and gigantism: some clinical characteristics of 50 patients]. 184 71

In chronic hypercalcemia, basal TSH has been found to be low, with normal serum circulating concentrations of T3 and T4. This observation suggested a potentiation by hypercalcemia of the thyroid secretory response to TSH. The present study was undertaken to assess the possible influence of hypercalcemia on the T3 secretory response to TSH. Since T3 secretion was studied after stimulation of endogenous TSH by TRH, it was first necessary to find a protocol enabling us to study the effect of calcium on T3 release without affecting TSH secretion. Eighteen subjects underwent two TRH tests, with and without simultaneous calcium infusion, at 2-week interval and in a randomized order. In group A (five subjects) calcium infusion started 1 min after TRH, in group B (five subjects) 10 min after TRH, and in group C (eight subjects) 20 min after TRH. In groups A and B, TSH secretion was markedly blunted by hypercalcemia. In contrast, when calcium infusion was started 20 min after TRH (group C), the TSH secretion profile was no longer different from that in the control study. However, in this situation the increments of T3 and free T3 120 and 180 min after TRH were significantly higher when the subjects were rendered hypercalcemic than in the control study. These findings suggest that calcium might act at two different levels, to enhance the thyroid secretory response to TSH and decrease TSH secretion by acting directly on the pituitary gland. Both effects would produce the association of low serum TSH and normal levels of T3 and T4 observed in chronic hypercalcemia.
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PMID:Effect of acute hypercalcemia on thyrotropin (TSH) and triiodothyronine responses to TSH-releasing hormone in man. 211 41

TSH serum levels and thyroid function in 32 patients with primary hyperparathyroidism and hypercalcemia were compared to those of 30 age and sex-matched normal subjects. Serum T3 and T4 concentrations in hyperparathyroidism were not different from normal. However, basal serum TSH concentrations measured with an ultrasensitive immunoradiometric assay were significantly lower than normal (1.09 +/- 0.49 vs 2.06 +/- 0.85 mU/l, p less than 0.001). In hyperparathyroidism, TSH, but not T4 or T3, was negatively correlated with serum calcium, not with iPTH. The increase in TSH (delta TSH) 30 min after the iv injection of TRH was also significantly blunted in patients with primary hyperparathyroidism; delta TSH was highly correlated with basal TSH in hypercalcemic patients. The basal TSH concentration was higher and no longer different from normal (1.70 +/- 1.2 mU/l) 2 to 12 months after removal of the parathyroid adenoma, when serum calcium was normalized, whereas T3 and T4 did not change. A low basal TSH with normal T4 and low T3 was found in 13 patients with hypercalcemia of malignancy. In these patients, TSH increased after treatment of hypercalcemia with 3-amino-l,hydroxypropylidene-1, 1-bisphosphonate, whereas T4 did not change. The results suggest that the set point of pituitary thyroid feedback control could be decreased in chronic hypercalcemia and that hypercalcemia could render the thyroid more sensitive to TSH.
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PMID:Low basal thyrotropin with normal thyroid function in primary hyperparathyroidism. 251 13

The effect of 1,25-dihydroxy-vitamin D3 (1,25-(OH)2-D3) on the TRH induced TSH release was investigated. Wistar rats were injected with 1,25-(OH)2-D3 (0.05 microgram/kg/day) for three days, and TRH was injected iv on the third day. Blood was drawn every 10 min during the following 40 min, and TSH was determined. The TSH release was significantly higher in rats treated with 1,25-(OH)2-D3 than in controls. The rats treated with 1,25-(OH)2-D3 were hypercalcaemic and thus, in order to find out if the effect was mediated through hypercalcaemia rats treated as above, were infused with EDTA (30 mg/kg/100 min) starting 60 min before the TRH test. This treatment made the rats normocalcaemic, and the significant increase in the TSH release was still seen in the 1,25-(OH)2-D3 treated rats as compared to controls. The results thus indicate that 1,25-(OH)2-D3 enhances the TRH induced TSH release and that the effect is not mediated through an increase in the serum calcium concentration at the time of the TRH test. In order to find out if the effect could be mediated by changes in intracellular calcium the rats were treated with the calcium antagonist verapamil (25 mg/kg/day) and the adrenergic blocker propranolol (5 mg/kg/day) alone or together with 1,25-(OH)2-D3. In rats treated with verapamil or propranolol alone or 1,25-(OH)2-D3 + propranolol, no effect was observed on the TRH induced TSH release. Verapamil + 1,25-(OH)2-D3 significantly increased the TSH release as compared to both controls and rats treated with 1,25-(OH)2-D3 alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The effect of 1,25-dihydroxy-cholecalciferol on the TRH induced TSH release in rats. 310 41

A female patient with acromegaly, hypercalcemia, and Zollinger-Ellison syndrome was found to have a very high plasma concentration (average 2,300 pmol/liter; normal less than 50 pmol/liter) of growth hormone-releasing factor as measured by a radioimmunoassay to human pituitary growth hormone-releasing factor-1-44. The plasma concentration of growth hormone averaged 25 mIU/liter (normal less than 5 mIU/liter) and there was no rise following an intravenous 100 micrograms bolus of human pituitary growth hormone-releasing factor-1-44. Plasma growth hormone and growth hormone-releasing factor levels were unaffected by bromocriptine, insulin-induced hypoglycemia, and sleep. A long-acting somatostatin analogue lowered both the growth hormone-releasing factor and the growth hormone levels. Thyrotropin-releasing hormone stimulation and oral glucose tolerance tests produced significant increases in plasma growth hormone levels whereas the growth hormone-releasing factor level remained unchanged, suggesting that when normal somatotrophs are exposed to maximal growth hormone-releasing factor stimulation, thyrotropin-releasing hormone becomes a secretagogue of growth hormone from the pituitary. It is proposed that in the absence of a radioimmunoassay for growth hormone-releasing factor, a lack of growth hormone response to growth hormone-releasing factor in a patient with acromegaly is compatible with a source of ectopic growth hormone-releasing factor production.
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PMID:Growth hormone secretion dynamics in a patient with ectopic growth hormone-releasing factor production. 392 80

In normal man 1,25 (OH)2-vitamin D3 [1,25 (OH)2D] increases both basal and TRH-stimulated prolactinemia; this effect is completely reversible by the calcium antagonist nifedipine. Similarly the 1,25 (OH)2D-induced hypercalcemia is totally inhibited by nifedipine. These findings suggest that both biological effects of 1,25 (OH)2D are mediated by calcium-dependent mechanisms.
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PMID:Effect of 1,25-dihydroxyvitamin D3 and nifedipine on prolactin release in normal man. 392 30

To determine the impact of induced hypo- and hypercalcemia on TRH (400 micrograms)-stimulated TSH and PRL release, healthy subjects (n = 11) were infused with 5% glucose in water (n = 11), disodium EDTA (n = 11), or calcium gluconate (n = 7). TRH was given as an iv bolus 60 min (5% glucose and EDTA) and 120 min (calcium) after initiation of the respective infusion. Basal plasma concentrations of TSH remained unchanged during induced hypo- and hypercalcemia, whereas those of PRL fell during the latter (P less than 0.05). The mean sum of increments (0-90 min) in PRL and TSH was considerably greater during hypocalcemia than during hypercalcemia (PRL, P less than 0.002; TSH, P less than 0.005). The increments in the plasma hormone concentration above basal after iv TRH were increased compared to those in normocalcemia (PRL, 98.4 +/- 37.9 ng/ml; TSH, 38.9 +/- 11.8 microU/ml) during hypocalcemia [PRL, 128 +/- 47.8 ng/ml (P less than 0.002); TSH, 46.7 +/- 12.8 microU/ml; (P less than 0.005)], but were impaired during hypercalcemia [PRL, 70.1 +/- 27 ng/ml (P less than 0.002); TSH, 28.9 +/- 8.5 microU/ml (P less than 0.025)]. The mean sum of increments in PRL was related to concentrations of both serum calcium (r = -0.59; P less than 0.01) and PTH (r = 0.51; P less than 0.05). A relation was also seen between the incremental responses of TSH and serum calcium (r = -0.52; P less than 0.05), PTH (r = 0.55; P less than 0.01), and phosphorus (r = -0.55; P less than 0.01). We conclude that in healthy man, TRH-mediated release of both PRL and TSH are inversely related to serum calcium concentrations in such a manner that hormone secretion is enhanced by acute hypocalcemia, but blunted by hypercalcemia.
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PMID:Effects of disodium EDTA and calcium infusion on prolactin and thyrotropin responses to thyrotropin-releasing hormone in healthy man. 640 62

The influence of changes in the serum calcium concentration on TSH secretion was evaluated in patients with primary hyperparathyroidism and idiopathic hypoparathyroidism and in normal subjects. Serum calcium concentrations were 12.7 +/- 0.8, 9.0 +/- 0.4, and 5.7 +/- 0.5 mg/100 ml in hyperparathyroid, normal, and hypoparathyroid subjects, respectively, and were significantly different from each other. Serum T3 and T4 concentrations were comparable among the three groups. The basal serum TSH concentration was highest in hypoparathyroid, lowest in hyperparathyroid, and intermediate in normal subjects. However, all values were within normal limits and were not significantly different from each other. TRH-stimulated TSH secretion was significantly greater in hypoparathyroid patients and significantly less in hyperparathyroid patients than in normal subjects, respectively. The TSH response to TRH was normalized when the serum calcium concentration was normalized by parathyroidectomy in a hyperparathyroid patient or by 1 alpha-hydroxyvitamin D3 administration in a hypoparathyroid patient. To further clarify the mechanism responsible for the modified TSH response to TRH in the hypercalcemic state, rats were made chronically hypercalcemic by the administration of 1 alpha-hydroxyvitamin D3 (0.2 micrograms/100 g BW, ip, for 10 days) and 3% calcium chloride in drinking water. The pituitary TSH content of hypercalcemic rats was significantly greater than that of control rats. The results suggest that decreased TSH secretion produced by chronic hypercalcemia is due to diminished TSH release, rather than to decreased pituitary TSH reserve.
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PMID:Thyrotropin secretion in patients with hyperparathyroidism or hypoparathyroidism: effect of serum calcium on thyrotropin release. 640 63

The responses of TSH and PRL to intravenous doses of 500 micrograms of TRH were investigated in 26 patients with primary hyperparathyroidism. Fourteen patients (54%) showed low responses of TSH with peak values of less than 5 microU/ml (Group A). Twelve patients showed normal responses of TSH to TRH (Group B). Among the 26, 12 cases belonging to Group A and eight in Group B were reexamined after the correction of serum calcium level by parathyroidectomy. After successful treatment, the responses of TSH to TRH in six of the 12 patients in Group A returned to normal, whereas those in the remaining six were unchanged. The responses in the eight patients in Group B after surgery were not changed when compared to those before treatment. The basal values of PRL and the responses of PRL to TRH were normal in all patients and did not change after treatment. We showed that patients with primary hyperparathyroidism have a high incidence (54%) of suppressed TSH response to TRH. Hypercalcemia was obviously one of the causative factors in inducing this abnormality in six patients. However, persistently suppressed responses of TSH to TRH were observed in the other six patients in Group A even after the correction of the serum calcium level by surgery. This finding suggests a primary failure of the TSH-regulatory mechanism in some cases of primary hyperparathyroidism.
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PMID:The suppression of TSH in the presence of the normal PRL responses to TRH out of 26 patients with primary hyperparathyroidism. 641 19

To investigate the influence of calcium ions on the secretion of anterior pituitary hormones in response to stimulation by exogenous hypothalmic releasing factors in man, we measured serum concentrations of pituitary hormones serially during a continuous infusion of combined TRH (2 micrograms/min) and GnRH (1 microgram/min), with concomitant iv saline or calcium administration. Compared to saline, calcium administration was associated with a significant increase in GnRH-TRH-stimulated LH and FSH release and a corresponding rise in serum testosterone concentrations. The effect of calcium ions on gonadotropin secretion was specific, because releasing factor-stimulated secretion of TSH and PRL was suppressed by hypercalcemia. Serum concentrations of GH were not significantly altered under these conditions. In summary, the present results provide the first in vivo evidence that acute infusion of calcium ions augments GnRH-TRH-stimulated secretion of LH and FSH, with an accompanying increase in serum testosterone levels. In contrast, hypercalcemia did not alter serum GH concentrations, and it suppressed GnRH-TRH-stimulated release of PRL and TSH. We conclude that calcium ions can selectively influence releasing factor-stimulated secretion of certain anterior pituitary hormones in man.
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PMID:Divergent influences of calcium ions on releasing factor-stimulated anterior pituitary hormone secretion in normal man. 642 72


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