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Query: UMLS:C0020437 (hypercalcemia)
 10,293 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Exposure of rainbow trout to a reduced ambient calcium level (from 490 to 25 mumol Ca2+/l) caused hypocalcaemia and induced a rapid increase (within 1 h) in systemic cortisol levels. Under conditions of low environmental calcium concentrations, cortisol levels remained increased for at least 8 days. After this time the in-vitro Ca2+-transport capacity of branchial basolateral membrane vesicles was increased due to stimulation of Ca2+-ATPase activity, presumably as a result of chloride cell proliferation. Pituitary prolactin cells were unaffected by low ambient calcium levels. Fish kept in water containing 490 mumol Ca2+/l and treated with cortisol for 7 days displayed an increase in whole body calcium uptake and an enhancement of the branchial calcium transport capacity; concomitantly, hypercalcaemia was observed. We conclude that, in the rainbow trout, cortisol exerts hypercalcaemic effects by stimulating Ca2+ uptake from the water and that this effect forms an intrinsic part of the established mineralocorticoid action of cortisol in fish.
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PMID:Cortisol stimulates whole body calcium uptake and the branchial calcium pump in freshwater rainbow trout. 252 90

In freshwater-acclimated American eels (Anguilla rostrata LeSueur), ovine prolactin and grafts of the part of the pituitary gland containing the prolactin cells induced hypercalcemia. The hypercalcemia was associated with increased uptake of calcium from the water (resulting from increased influx and decreased efflux) and with enhanced high-affinity Ca2+-adenosinetriphosphatase (ATPase) activity in the gills, the putative biochemical correlate of the branchial Ca2+ pump. Kinetic analyses of ATPase-mediated Ca2+ transport in plasma membrane vesicles of branchial epithelium provided evidence that prolactin enhanced the maximum velocity of the Ca2+ pump. Prolactin treatments raised plasma cortisol levels slightly but significantly in eels. However, cortisol per se was not hypercalcemic in eels and did not stimulate the branchial Ca2+ pump. We conclude that the hypercalcemic potency of prolactin in fish relates to its stimulatory action on active Ca2+ transport in the gills.
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PMID:Calcitropic actions of prolactin in freshwater North American eel (Anguilla rostrata LeSueur). 252 94

In order to examine the dynamics of ion regulation, osmoregulation, and plasma calcitonin during the parr-smolt transformation (smoltification), blood and gill tissue were collected from yearling coho salmon, Oncorhynchus kisutch, from February to October. Fish were kept in fresh water (FW) throughout this period. In addition, fish were exposed to seawater (SW) at the peak of smoltification in mid-April, and samples from these fish were collected until July. Plasma osmolality, gill Na+,K+-ATPase activity, plasma levels of calcitonin, and free and total calcium and magnesium were measured. SW adaptability of FW fish was assessed throughout the study by measurements of plasma osmolality following a 24-hr exposure to seawater. The greatest hypoosmoregulatory ability occurred in April-May, although SW-adapted fish had higher plasma osmolality than FW-adapted fish at all times. Gill Na+,K+-ATPase activity in FW-adapted fish increased from April to June and increased rapidly following exposure of fish to SW, and remained elevated in SW-adapted fish. Free plasma calcium and magnesium levels increased following SW exposure, but returned to prior levels within 1 week. Netting and confinement stress during sampling caused an increase in plasma osmolality and free calcium and magnesium levels in both FW- and SW-adapted fish. Changes in hypoosmoregulatory ability during smoltification and SW adaptation were correlated with changes in gill Na+,K+-ATPase activity. A sharp transitory peak in plasma calcitonin levels occurred early in smoltification (March) and in SW-adapted fish in June. Plasma calcitonin levels gradually increased in FW-adapted fish during the period of desmoltification. However, no change in plasma calcitonin levels occurred during SW-induced hypercalcemia, suggesting that the hormone does not play a major role in short-term plasma calcium regulation in coho salmon.
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PMID:Smoltification and seawater adaptation in coho salmon (Oncorhynchus kisutch): plasma calcium regulation, osmoregulation, and calcitonin. 254 13

Previous studies revealed that administration of 24,25-dihydroxyvitamin D3 [24,25-(OH)2D3] to calcium (Ca)-deficient rats causes a dose-dependent reduction in markedly elevated serum 1,25-(OH)2D3 level. Although the results suggested that the metabolism of 1,25-(OH)2D3 was accelerated by 24,25-(OH)2D3, those experiments could not define whether the enhanced metabolism of 1,25-(OH)2D3 played a role in the reduction in the serum 1,25-(OH)2D3 level. In the present study, in order to address this issue more specifically, serum 1,25-(OH)2D3 was maintained solely by exogenous administration through miniosmotic pumps of 1,25-(OH)2D3 into vitamin D-deficient rats. Thus, by measuring the serum 1,25-(OH)2D3 concentration, the effect of 24,25-(OH)2D3 on the MCR of 1,25-(OH)2D3 could be examined. Administration of 24,25-(OH)2D3 caused a dose-dependent enhancement in the MCR of 1,25-(OH)2D3, and 1 microgram/100 g rat.day 24,25-(OH)2D3, which elevated serum 24,25-(OH)2D3 to 8.6 +/- 1.3 ng/ml, significantly increased MCR and suppressed serum levels of 1,25-(OH)2D3. The effect of 24,25-(OH)2D3 on 1,25-(OH)2D3 metabolism developed with a rapid time course, and the recovery of iv injected [1 beta-3H]1,25-(OH)2D3 in blood was significantly reduced within 1 h. In addition, there was an increase in radioactivity in the water-soluble fraction of serum as well as in urine, suggesting that 1,25-(OH)2D3 is rapidly degraded to a water-soluble metabolite(s). Furthermore, the reduction in serum 1,25-(OH)2D3 was associated with a reduction in both serum and urinary Ca levels. Because the conversion of [3H]24,25-(OH)2D3 to [3H]1,24,25-(OH)2D3 or other metabolites was minimal in these rats, 24,25-(OH)2D3 appears to act without being converted into other metabolites. These results demonstrate that 24,25-(OH)2D3 rapidly stimulates the metabolism of 1,25-(OH)2D3 and reduces its serum level. It is suggested that 24,25-(OH)2D3 plays a role in modifying serum 1,25-(OH)2D3 concentrations by affecting the metabolism of 1,25-(OH)2D3 and may have a therapeutic values in the treatment of hypercalcemia or hypercalciuria caused by 1,25-(OH)2D3 excess.
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PMID:Effect of 24,25-dihydroxyvitamin D3 on 1,25-dihydroxyvitamin D3 [1,25-(OH)2D3] metabolism in vitamin D-deficient rats infused with 1,25-(OH)2D3. 278 9

Disorders of fluid and electrolyte metabolism in elderly diabetics were studied. High frequency of hyperkalemia (20.8%), hypomagnesemia (14.6%), hypocalcemia (13.7%), hyperphosphatemia (8.6%), hyponatremia (8.1%) and hyperchloremia (7.2%) was observed among 332 elderly diabetics. Furthermore, hyperkalemia, hyperphosphatemia, hyponatremia, hyperchloremia, hypercalcemia and hypermagnesemia were more frequent in diabetics with renal insufficiency (serum Cr greater than or equal to 1.5 mg/dl) than in diabetics with normal renal function (serum Cr less than or equal to 1.4 mg/dl). In addition, statistically significant negative correlation were observed between plasma glucose levels and serum levels of sodium and chloride in diabetics with normal renal function. These results clearly demonstrated that the most important causal factor of electrolyte disorders in elderly diabetics might be the renal dysfunction due to diabetic nephropathy and/or nephrosclerosis. Moreover, glucose intolerance is also one of the causal factors for hyponatremia and hypochloremia. Disorders of fluid and electrolyte metabolism were manifest in 31 diabetic patients with hyperosmolar non-ketotic coma. The frequency of patients with abnormally elevated serum levels of sodium, potassium and chloride, and patients with abnormally lowered serum levels of calcium was high in this morbid state. Water and sodium deficit, examined in 11 cases of hyperosmolar non-ketotic coma, was 4780 +/- 2100 ml (107 +/- 43 ml/kg body weight) and 290 +/- 170 mEq (6.8 +/- 4.2 mEq/kg body weight), respectively. However, no significant deficit of potassium was observed in the patients. Statistically significant positive correlations between water deficit and serum Cr levels and with serum effective osmolarity were observed. However, there were no significant correlations between water deficit and plasma glucose levels, serum sodium levels and serum osmolarity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:[Disorders of fluid and electrolyte metabolism in elderly diabetics]. 279 74

A strong correlation between the biochemical manifestations of hyperparathyroidism and the volume of abnormal parathyroid tissue could be used to guide the extent of surgical exploration and parathyroid gland resection (i.e., finding a small "adenoma" in a patient with marked hypercalcemia would dictate further exploration). We examined this relationship in patients for whom data were collected prospectively (n = 14) and retrospectively (n = 27). We considered only patients cured after excision of a single gland and glands for which a three-dimensional description or volume of water displacement was available. To exclude artifactually elevated serum concentrations of parathyroid hormone (PTH), PTH values were used only from patients with levels of serum creatinine less than 2 mg/dl. To accommodate different assays, highest preoperative PTH, ionized calcium, and alkaline phosphatase (AP) values were expressed as percent above upper normal limit. There was excellent agreement (r = 0.93, p less than 0.05) between measured and calculated gland volume. In the prospective study (but not in the retrospective study) there was a significant (p less than 0.05) correlation (r = 0.61) between gland volume and highest preoperative total calcium value; however, there was considerable variation in gland size in patients with similar calcium levels. In neither study was there a significant correlation between gland volume and any of the following: calcium, ionized calcium, midregional PTH, carboxyterminal PTH, or intact PTH, alkaline phosphatase, and urine cyclic adenosine monophosphate (AMP). In the prospective study there was a tendency for urine cyclic AMP, ionized calcium, and AP to increase with increasing gland volume (r = 0.42, 0.45, and 0.51, respectively). Preoperative measurements of calcium, PTH, urine cyclic AMP, and AP are too inconsistent to rely on for determining the extent of parathyroid gland resection.
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PMID:Can the volume of abnormal parathyroid tissue be predicted by preoperative biochemical measurement? 282 7

1. Changes in plasma calcium levels, in response to salmon calcitonin injections, were studied in freshwater and sea-water adapted trout (Salmo gairdnerii) and in grey mullet (Chelon labrosus). 2. Low doses (0.1 ng sCT/100 g body weight) elicited hypercalcemia in the two species studied. 3. High doses (0.5 microgram) provoked hypocalcemia only in freshwater and sea-water adapted trout. 4. An hypercalcemic response appears as the primordial effects of CT injections, higher doses of CT leading to hypocalcemic effects.
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PMID:Calcitonin induces hypercalcemia in grey mullet and immature freshwater and sea-water adapted rainbow trout. 288 70

A unique chemical intoxication by Dead Sea water and its resultant physiological effects of combined severe hypercalcemia and hypermagnesemia are described. Of 48 adult patients, 16 had at least one severe clinical manifestation of either disturbed sensorium or a syndrome similar to adult respiratory distress syndrome. The patients had tachyarrhythmias (11 of 38, 29%), conduction disturbance (nine of 37, 24%), and a normal QTc interval in the presence of severe hypercalcemia. Combined respiratory and metabolic acidosis and concomitant extreme hypercalcemia and hypermagnesemia, reaching serum levels up to 28.8 and 33 mg/dL, respectively, were responsible for most of the clinical findings. The adult mortality was 19%. Four pediatric patients with variable degrees of intoxication survived. Discriminant function analysis determined that admission serum calcium concentration of more than 15.5 mg/dL was the best predictor of mortality. In patients with severe intoxication, supportive medical treatment, including forced diuresis, was disappointing. Early dialysis for severe cases merits further study.
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PMID:Dead Sea water poisoning. 291 85

The present study was undertaken to investigate the cAMP system in isolated vasopressin (AVP)-sensitive segments of the hypercalcemic rat. Hypercalcemia was produced by supplementation of diet with dihydrotachysterol, achieving a mean serum calcium of 12.6 mg%. Maximal urinary concentration was only 1982 +/- 119 mOsm/kg H2O in pair, watered hypercalcemic rats when compared to 2478 +/- 93 mOsm/kg H2O in controls (N = 7) (P less than 0.01). Vasopressin stimulated adenylate cyclase activity at concentrations of vasopressin between 10(-9) and 10(-7) M was indistinguishable in the outer medullary collecting duct (OMCD) and inner medullary collecting duct (IMCD) of tubules dissected from hypercalcemic rats or normocalcemic rats. Likewise, in situ cAMP accumulation in response to 10(-7) M AVP was not significantly different in either OMCD or IMCD of hypercalcemic or normocalcemic rats at either isotonic or hypertonic media conditions. In contrast, while 10(-7) M AVP significantly (P less than 0.05) increased cAMP accumulation in the medullary ascending limb (MAL) of normocalcemic rats it failed to do so in the MAL of hypercalcemic rats. This failure to accumulate cAMP appears to be due to impairment in AVP-stimulated adenylate cyclase rather than to enhanced phosphodiesterase activity. A similar decrement in glucagon stimulated adenylate cyclase occurred with 10(-6) M glucagon. The results demonstrate that in chronic hypercalcemia the cAMP system in the OMCT and IMCD of the rat is intact, but the MAL demonstrates abnormal AVP responsiveness due to impaired adenylate cyclase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:The cAMP system in vasopressin-sensitive nephron segments of the vitamin D-treated rat. 303 55

After 7 days in air on wet filter paper mudskippers had normal body weight and normal levels of plasma sodium, potassium, and phosphate. They were, however, significantly hypercalcemic. The hypercalcemia could be reduced by the daily intraperitoneal injection of synthetic eel calcitonin (1.67 microgram kg-1 day-1) and this effect was dose dependent with a maximal response at a dose of 3.33 micrograms kg-1 day-1. Calcitonin had no effect on plasma calcium levels of fish held in water but did induce significant hyperphosphatemia whether the fish were held in water or in air on wet filter paper with this effect being greater under the latter conditions. The hypocalcemic action of calcitonin was restricted to conditions under which the fish displayed patent hypercalcemia. Under no conditions did calcitonin produce significant hypocalcemia so it appears that the action of synthetic eel calcitonin in the mudskipper, Periophthalmodon schlosseri, is dependent upon the presence of excess plasma calcium and is thus more accurately described as being anti-hypercalcemic rather than hypocalcemic.
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PMID:Effects of calcitonin on plasma calcium and phosphate in the mudskipper, Periophthalmodon schlosseri (Teleostei), in water and during exposure to air. 338 5


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