Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0028754 (obesity)
 124,988 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The interactions of serum levels of magnesium and parathyroid hormone (PTH) have been studied in a patient with hypomagnesemia and hypocalcemia following intestinal bypass surgery for obesity. When serum magnesium was low serum PTH was not stimulated by hypocalcemia. With correction of magnesium deficiency hypocalcemia was associated with elevation of serum PTH levels. Infusion of exogenous PTH induced a clearly detectable renal response in the presence of hypomagnesemia but the response was diminished when serum magnesium was elevated. In this patient it appears that hypomagnesemia suppressed parathyroid gland activity, leaving the renal action of PTH intact.
 ...
PMID:Influence of magnesium on the secretion and action of parathyroid hormone. 23 Oct 63

Thirty-four patients were studied 2--6 years after jejunoileal bypass for morbid obesity. The serum concentration of 25-hydroxyvitamin D (25-OHD) were reduced and related to the frequency fo stools and to the weight reduction. Fifteen patients were not able to normalize serum 25-OHD following a long-term regular vitamin D intake. The serum immunoreactive parathyroid hormone concentration (iPTH) and the alkaline phosphatase levels were elevated in this group, indicating a secondary hyperparathyroidism. The mean bone mineral content of the forearm was reduced 3--6 years after the operation, most severely in those with elevated serum iPTH. The desired weight reduction by jejunoileal shunt was obtained at the expense of a severely disturbed vitamin D metabolism. We suggest, that all patients with an intestinal bypass for obesity should receive regular vitamin D supplement, and serum 25-OHD should be measured in order to monitor the effect of therapy.
 ...
PMID:Impairment of vitamin D and bone metabolism in patients with bypass operation for obesity. 28 17

Though tetany is not among the reported side effects of oral contraceptive usage, specifically of the use of estrogen, a case study is reported which links the development of tetany to administration of estrogen-containing oral contraceptives. The case was a 35-year-old woman, who presented with muscular cramps and hypocalcemia of unknown origen. 4 years earlier, shortly after taking an oral contraceptive preparation, she had experienced the same symptoms; now, she was reacting apparently to treatment with chorionic gonadotropins for mild obesity. Clinically, she evinced persistent hypocalcemia, hyperphosphatemia, normal renal function, and low plasma parathyroid hormone (PTH); such characteristics are consistent with hypoparathyroidism. With the former, no PTH response was measured, whereas with the latter antiserum, normal response of PTH was found; hence, it was concluded that the patient's PTH was immunologically abnormal and biologically ineffective. These data support the hypothesis that estrogens have a PTH-independent effect on bone; i.e., oral administration of estogens (in this case ethinylestradiol) caused hypocalcemia with tetanic symptoms resulting from estrogenic inhibition of bone resorption by specific action on the bone, not by antagonizing PTH action in vivo.
 ...
PMID:Estrogen-induced tetany in idiopathic hypoparathyroidism. 82 Jun 24

Obesity is associated with altered bone mass. However, reports on bone status in obesity are inconsistent. Increased or normal bone mass was reported in obese adults but decreased bone mineral content was described in obese children. Therefore we evaluated the obese fa/fa rat as a possible model to assist in studies of bone metabolism in obesity. Obese and lean 14-week-old male rats underwent 24 h balance studies for calcium, magnesium and phosphate. Plasma calcium, magnesium, phosphate, immunoreactive parathyroid hormone, urinary cAMP (cyclic adenosine monophosphate) and femur bone histomorphometry were also analysed. Obese rats were heavier and had higher plasma insulin, cholesterol and triglycerides levels (P less than 0.05). A comparable positive balance for calcium, magnesium and phosphate was found in obese and lean rats. Total plasma calcium was higher in the obese, but albumin corrected calcium and plasma magnesium, phosphate and glucose were similar to the lean. In contrast to human obesity, obese rats were hypercalciuric, hypermagnisuric and hyperphosphaturic (P less than 0.05). iPTH and urinary cAMP were higher in the obese. Femora of fa/fa rats were shorter and lighter. Their bone osteoid surface and bone calcium content were similar to controls. Femora metaphysis in the obese had increased number of trabeculae, decreased trabecular width and higher erosion surface/bone surface ratio. Their diaphysis had increased cortical area/bone area and cortical width/bone width ratios and decreased medullary area. In summary, obese rats have higher iPTH, are hypercalciuric and have decreased bone mass. These last two observations differ from what is described in adult human obesity. Therefore, the obese fa/fa rat is of limited assistance in studies of bone status in adult human obesity. It might be of help in studies of bone metabolism in juvenile obesity.
 ...
PMID:Bone structure and calcium metabolism in obese Zucker rats. 131 32

An animal model of postmenopausal bone loss can be defined as a living animal in which spontaneous or induced bone loss due to ovarian hormone deficiency can be studied, and in which the characteristics of the bone loss and its sequalae resemble those found in postmenopausal women in one or more respects. Although in comparison to humans, the skeletal mass of rats remains stable for a protracted period during their lifespan, rats can be ovariectomized to make them sex-hormone deficient, and to stimulate the accelerated loss of bone that occurs in women following menopause. Ovariectomy induced bone loss in the rat and postmenopausal bone loss share many similar characteristics. These include: increased rate of bone turnover with resorption exceeding formation; and initial rapid phase of bone loss followed by a much slower phase; greater loss of cancellous than cortical bone; decreased intestinal absorption of calcium; some protection against bone loss by obesity; and similar skeletal response to therapy with estrogen, tamoxifen, bisphosphonates, parathyroid hormone, calcitonin and exercise. These wide-ranging similarities are strong evidence that the ovariectomized rat bone loss model is suitable for studying problems that are relevant to postmenopausal bone loss.
 ...
PMID:The ovariectomized rat model of postmenopausal bone loss. 177 31

Gastric exclusion has been introduced as a surgical treatment for morbid obesity. We describe two women who had undergone gastric bypass for obesity with metabolic bone disease and secondary hyperparathyroidism. In one patient transiliac bone biopsy after double tetracycline labelling demonstrated histologic evidence of hyperparathyroidism with osteitis fibrosa cystica. Six additional women who had undergone gastric exclusion were evaluated. Serum phosphorus, calcium, and creatinine were normal in all but one patient who had hypocalcemia. Serum immunoreactive parathyroid hormone was elevated in seven of eight patients and urinary calcium was less than or equal to 2 mmol/d (80 mg/24 h) in 6 patients. Lumbar spine bone mineral density was 86 +/- 7 (mean +/- SE) per cent of predicted and femoral neck bone mineral density was 89 +/- 6 per cent of predicted. Women who have had gastric exclusion for obesity may develop secondary hyperparathyroidism which could result in loss of bone mass.
 ...
PMID:Secondary hyperparathyroidism and osteopenia in women following gastric exclusion surgery for obesity. 179 Apr 6

Serum immunoreactive parathyroid hormone (PTH) is increased in obese as compared with nonobese subjects and declines with weight loss. To determine whether alteration of the vitamin D-endocrine system occurs in obesity and whether ensuing secondary hyperparathyroidism is associated with a reduction in urinary calcium, a study was performed in 12 obese white individuals, five men and seven women, and 14 nonobese white subjects, eight men and six women, ranging in age from 20 to 35 yr. Body weight averaged 106 +/- 6 kg in the obese and 68 +/- 2 kg in the nonobese subjects (P less than 0.01). Each of them were hospitalized on a metabolic ward and were given a constant daily diet containing 400 mg of calcium and 900 mg of phosphorus. Whereas mean serum calcium, serum ionized calcium, and serum phosphorus were the same in the two groups, mean serum immunoreactive PTH (518 +/- 48 vs. 243 +/- 33 pg/ml, P less than 0.001), mean serum 1,25-dihydroxyvitamin D [1,25(OH)2D] (37 +/- 2 vs. 29 +/- 2, P less than 0.01), and mean serum Gla protein (33 +/- 2 vs. 24 +/- 2 ng/ml, P less than 0.02) were significantly higher, and mean serum 25-hydroxyvitamin D (25-OHD) (8 +/- 1 vs. 20 +/- 2 ng/ml, P less than 0.001) was significantly lower in the obese than in the nonobese men and women. Mean urinary phosphorus was the same in the two groups, whereas mean urinary calcium (115 +/- 10 vs. 166 +/- 13 mg/d, P less than 0.01) was significantly lower, and mean urinary cyclic AMP (3.18 +/- 0.43 vs. 1.84 +/- 0.25 nM/dl GF, P less than 0.01) and creatinine clearance (216 +/- 13 vs. 173 +/- 6 liter/d, P less than 0.01) were significantly higher in the obese than in the nonobese individuals. There was a significant positive correlation between percentage of ideal body weight and urinary cyclic AMP (r = 0.524, P less than 0.01) and between percentage of ideal body weight and serum immunoreactive PTH (r = 0.717, P less than 0.01) in the two groups. The results provide evidence that alteration of the vitamin D-endocrine system in obese subjects is characterized by secondary hyperparathyroidism which is associated with enhanced renal tubular reabsorption of calcium and increased circulating 1,25(OH)2D. The reduction of serum 25-OHD in them is attributed to feedback inhibition of hepatic synthesis of the precursor by the increased serum 1,25(OH)2D.
 ...
PMID:Evidence for alteration of the vitamin D-endocrine system in obese subjects. 299 40

To evaluate whether changed plasma calcium binding might lead to a secondary increase of parathyroid hormone in morbid obesity, fasting measurements of serum ionized, ultrafiltrable and total calcium, calcium binding substances, and parathyroid hormone were undertaken in age- and sex-matched groups of obese (n = 44) and normal weight subjects (n = 52). The 24-hour urinary calcium excretion and clearance of creatine were also measured. Calcium binding to proteins was changed. Serum total proteins and protein-bound calcium did not differ, but serum albumin was decreased in obesity. Consequently, obese subjects did not reveal the normal dependency of protein-bound calcium upon albumin. Calcium binding to other substances was also changed. Serum phosphate and bicarbonate were decreased, while the concentrations of citrate, lactate, acetoacetate, 3-hydroxybutyrate, free fatty acids, and urate were all increased, leaving the total concentration of plasma complex-bound calcium unchanged. Nevertheless, these reciprocal changes increase the concentrations of less readily reabsorbable anions in the renal ultrafiltrate. The changed pattern of calcium binding in serum of the obese subjects may serve to explain our findings of increased urinary calcium excretion, lowering of serum ionized calcium and increased parathyroid hormone levels, changes being significantly correlated with degree of overweight.
 ...
PMID:Increased parathyroid hormone as a consequence of changed complex binding of plasma calcium in morbid obesity. 308 Jun 52

In order to test the relation between obesity and the secondary hyperparathyroidism found in markedly overweight subjects, 24 morbidly obese patients were studied before and after a weight loss of 35.9 kg obtained by a nutritionally adequate, intermittent very-low-calorie diet. Overweight was reduced from 98 +/- 34% to 44 +/- 19%. Serum total calcium did not change, but serum ionized calcium (Ca2+) increased from 1.22 +/- 0.04 mmol/L to 1.25 +/- 0.04 mmol/L (P less than .001). A corresponding fall was observed in serum parathyroid hormone (s-PTH), which decreased from 47.2 +/- 21.7 pmol/L to 35.2 +/- 19.4 pmol/L (P = .01). The change of s-PTH was positively associated with the reduction of body weight (r = .50, P less than .05) and with the reduction of overweight (r = .55, P less than .01). Regarding calcium binding substances, serum albumin remained low. The initially lowered serum phosphate and bicarbonate both rose (P less than .001). Plasma lactate and plasma free fatty acids (FFAs) decreased (P less than .001). The study supports our hypothesis that the change profile of calcium complexing anions in obesity interferes with the tubular reabsorption of calcium, which in turn lowers serum Ca2+, thus promoting hyperparathyroidism. Along with weight loss, concentrations of calcium complexing anions returns towards normal values and the secondary hyperparathyroidism regresses.
 ...
PMID:Secondary hyperparathyroidism of morbid obesity regresses during weight reduction. 336 88

As compared to nonobese white men and women, age-matched nonobese black subjects and obese white individuals show alterations in the vitamin D-endocrine system that are characterized by increases in mean serum immunoreactive parathyroid hormone (PTH), serum 1,25-dihydroxyvitamin D [1,25-(OH)2D], and urinary cyclic adenosine 3,5-monophosphate (cAMP) and by decreases in mean serum 25-hydroxyvitamin D (25 OHD) and in urinary calcium. Thus, both groups show secondary hyperparathyroidism which is associated with increased renal tubular reabsorption of calcium and increased renal synthesis of 1,25-(OH)2D. In view of these findings, studies were conducted in 10 obese black subjects (3 men and 7 women) and in 12 nonobese black individuals (7 men and 5 women), ranging in age from 20 to 35 yr, to determine whether obesity influences the vitamin D-endocrine system in blacks. Body weight averaged 99 +/- 4 kg in the obese and 73 +/- 3 kg in the nonobese subjects (p less than .001). All of them were hospitalized on a metabolic ward and were given a constant daily diet containing 400 mg of calcium, 900 mg of phosphorus, 110 meq of sodium, 65 meq of potassium, and 18 meq of magnesium.(ABSTRACT TRUNCATED AT 250 WORDS)
 ...
PMID:Evidence that obesity does not influence the vitamin D-endocrine system in blacks. 350 35


1 2 3 4 5 6 7 8 9 10 Next >>