Age‐related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of bone metabolism in Chinese women

Chan, Elton; Lau, Edith M. C.; Shek, Chi Chung; MacDonald, D.; Woo, Jean; Leung, Ping Chung; Swaminathan, R.

doi:10.1111/j.1365-2265.1992.tb01463.x

Cited by 38 publications

(22 citation statements)

References 47 publications

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“…1,25(OH) 2 D concentrations were not related to age in this study. This is consistent with studies conducted by Ebeling et al (1994) and Chan et al (1992), which reported that the increase in endogeneous production of 1,25(OH) 2 D induced by a low calcium diet was age independent.…”

Section: Discussionsupporting

confidence: 93%

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Vitamin D status and parathyroid hormone concentrations in Chinese women and men from north-east of the People’s Republic of China

et al. 2000

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D) and PTH using radioimmunoassays. The proportion of subjects who could be regarded as vitamin D de®cient (`25 nmolal) was 48%, 29%, 15% and 13% for old men, young men, old women and young women, respectively. There was no association between plasma 1,25(OH) 2 D and 25(OH)D concentrations. PTH concentrations were elevated in both old women and men compared with young subjects (P`0.01). A negative association between PTH and 25(OH)D was only found in old women (P`0.001), but not in old men, nor in young subjects. Conclusions: Vitamin D status was poor in this population in early spring, especially in men. There was no clear evidence to show that the secretion of PTH and the conversion of 1,25(OH) 2 D were affected by the low 25(OH)D concentration.

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Section: Discussionsupporting

confidence: 93%

“…This is consistent with studies in both Caucasian and Asian populations (Chan et al, 1992;. The mild increase in PTH secretion with ageing may represent a compensatory response to the age-related decline in the level of renal 1a-hydroxylase or its sensitivity to normal physiological stimuli (Sherman et al, 1990).…”

Section: Discussionsupporting

confidence: 91%

Vitamin D status and parathyroid hormone concentrations in Chinese women and men from north-east of the People’s Republic of China

et al. 2000

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“…As a consequence, serum levels of PTH are elevated (Armbrecht et al, 1984;Chan et al, 1992). Accordingly, the bioactivity of PTH, as indicated by blood osteocalcin concentration, renal production of cAMP, and phosphorus diuresis, increases with age (Marcus et al, 1984).…”

Section: Discussionmentioning

confidence: 98%

“…levels (Chan et al, 1992) and decreased serum vitamin D metabolites (Armbrecht et al, 1984), intestinal calcium absorption (Horst et al, 1978), and bone density (Hui et al, 1988 (Massheimer et al, 1995). In addition, the transient and biphasic production of IP 3 and DAG generated by the hormone significantly decreased with senescence (De Boland et al, 1996).…”

mentioning

confidence: 97%

Effect of aging on the mechanisms of PTH-induced calcium influx in rat intestinal cells

et al. 2000

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We have investigated the effects of aging on parathyroid hormone (PTH) modulation of intracellular calcium homeostasis and their relationship to signal transduction pathways in isolated rat duodenal cells (enterocytes). PTH (10(-8)-10(-9) M) increased enterocyte (45)Ca(2+) influx and intracellular Ca(2+) concentration ([Ca(2+)](i)) to a greater extent (twofold and 50%, respectively) in aged (24 months) than in young (3 months) animals. The [Ca(2+)](i) response of old cells to the hormone was slower, lacking the early phase of changes in cytosolic Ca(2+). Ca(2+) influx induced by PTH was prevented by the protein kinase A antagonist Rp-cAMPS in both young and aged enterocytes, whereas neomycin and compound U73122, inhibitors of PLC-catalyzed phosphoinositide hydrolysis, abolished hormone-dependent Ca(2+) influx in young but had no effect on aged cells. Higher basal adenylyl cyclase (AC) activity and cAMP content were detected in old enterocytes. PTH increased the absolute levels of cAMP in aged cells and AC activity of microsomes isolated therefrom to a greater extent (>/= twofold) than in young enterocytes/membranes. In young cells, the hormone also induced a rapid and transient release of inositoltrisphosphate (IP(3)) and diacylglycerol (neomycin-sensitive) at 45 sec, and a delayed phase of DAG at 5 min (neomycin-insensitive). The early formation of IP(3) and DAG was blunted in aged animals. These results suggest that both the PLC and adenylyl cyclase cascades are involved in PTH stimulation of Ca(2+) influx in duodenal cells. During aging, however, only the cAMP pathway is operative, mediating a potentiation of the effects of the hormone. Additional studies are required to establish the relative role of PTH-dependent messenger systems in the regulation of intestinal calcium absorption and age-related abnormalities.

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“…4). With age there is an increase in serum PTH and bone turnover [56][57][58][59][60][61] due to the combined effects of reduced calcium intake [62] and absorption [63][64][65] and to vitamin D insufficiency [61,66]. Calcium supplementation is most effective in this situation.…”

Section: Skeletal Pathophysiologymentioning

confidence: 99%

Effects of Calcium and Vitamin D Insufficiency on the Skeleton

Peacock

1998

Osteoporos Int

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Age‐related changes in bone density, serum parathyroid hormone, calcium absorption and other indices of bone metabolism in Chinese women

Abstract: In Chinese women there is an increase in PTH and a decrease in calcium absorption with age in spite of the presence of normal vitamin D metabolites.

Cited by 38 publications

References 47 publications

Vitamin D status and parathyroid hormone concentrations in Chinese women and men from north-east of the People’s Republic of China

Vitamin D status and parathyroid hormone concentrations in Chinese women and men from north-east of the People’s Republic of China

Effect of aging on the mechanisms of PTH-induced calcium influx in rat intestinal cells

Effects of Calcium and Vitamin D Insufficiency on the Skeleton

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