Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.2.1.108 (lactase)
 2,133 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Serum levels of osteocalcin, a noncollagenous bone matrix protein, have been found to be a specific biochemical parameter of bone formation. In the literature in subjects with osteoporosis, an increased incidence of lactase deficiency has been described. We therefore determined the serum levels of osteocalcin in 10 patients with lactase deficiency and in 20 control subjects by radioimmunoassay. The patients with lactase deficiency were dietary treated and had a very low daily calcium intake. Serum osteocalcin levels were significantly higher in the patients with lactase deficiency than in the control subjects. In contrast, serum levels of parathyroid hormone, alkaline phosphatase, calcium, and phosphorus were not statistically different in the two groups. Our data suggest an increased rate of bone turnover in patients with lactase deficiency on a low calcium diet; possibly calcium supplementation is indicated in dietary-treated patients with lactase deficiency.
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PMID:Increased serum osteocalcin levels in patients with lactase deficiency. 189 34

Three men with osteoporotic fractures were found to have lactase deficiency and low dietary calcium intakes, decreased urinary calcium, and moderately increased serum osteocalcin and parathyroid hormone levels. Histomorphometric studies demonstrated increases in osteoid parameters and resorption surfaces. The few studies of the links between osteoporosis and lactase deficiency have yielded discordant results. A low calcium intake due to aversion to dairy products caused by the lactase deficiency may promote the development of osteoporosis.
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PMID:Lactose intolerance and osteoporosis in men. 881 61

Lactose malabsorption (LM; adult-type hypolactasia), an autosomal recessive condition, results from the down-regulation of the activity of lactase enzyme in the intestinal wall. In previous studies the effect of LM on bone mass, bone turnover rate, development of osteoporosis and osteoporotic fractures has remained controversial. We have recently identified a single nucleotide polymorphism (SNP), a C to T change residing 13910 base pairs upstream of the lactase (LCT) gene at chromosome 2q21-22, which shows complete association with lactase persistence, with the C/C-13910 genotype defining LM and the genotypes C/T-13910 and T/T-13910 lactase persistence. The present study was undertaken to examine the relationship of the C/T-13910 polymorphism to peak bone mass, bone turnover rate, and stress fractures among young Finnish men. The study population comprised 234 young men, aged 18.3 to 20.6 years, 184 men were recruits of the Finnish Army, and 50 were men of similar age who had postponed their military service for reasons not related to health. Bone mineral content (BMC), density (BMD), and scan area were measured in the lumbar spine and upper femur by dual-energy X-ray absorptiometry (DXA). Blood was sampled for genotyping of the C/T-13910 polymorphism and determination of serum 25-hydroxyvitamin D (25OHD), intact parathyroid hormone (iPTH), type I procollagen aminoterminal propeptide (PINP), and tartrate-resistant acid phosphatase 5b (TRACP5b). Second-void urine samples were collected for the determination of type I collagen aminoterminal telopeptide (NTX). The prevalence of the C/C-13910-genotype of these young adults did not differ significantly from the corresponding population prevalence of C/C-13910 (17.1% vs 18.1%) among Finnish blood donors. Fifteen recruits of the army experienced a stress fracture; 3 of them (20%) had the C/C-13910-genotype. Calcium intake was similar for the three genotypes as were the unadjusted BMCs, scan areas, and BMDs at different measurement sites. The adjustments for age, height, weight, smoking, alcohol consumption, and physical exercise in the multiple regression analysis did not reveal any significant relationships between the lactase genotypes and BMDs at lumbar (P = 0.16), femoral neck (P = 0.99) or total hip (P = 0.96) sites. Serum 25OHD, iPTH, and bone marker levels were similar for the C/C-13910 C/T-13910 and T/T-13910 genotypes. In summary, in young Finnish men, molecularly defined lactose malabsorption does not alter bone turnover rate and impair the acquisition of peak bone mass. Moreover, the C/C-13910 genotype does not seem to be a risk factor for stress fractures in army recruits.
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PMID:Molecularly defined lactose malabsorption, peak bone mass and bone turnover rate in young finnish men. 1536 57