Declining Adrenal Androgens: An Association with Bone Loss in Aging Women

Wild, Robert A.; Buchanan, J.R.; Myers, Cathleen; Demers, Laurence M.

doi:10.3181/00379727-186-42625

Cited by 99 publications

(51 citation statements)

References 23 publications

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“…For example, DHEAS levels were correlated with skeletal maturation [37]. Additionally, DHEAS is positively correlated to BMD and declines with age [38][39][40][41]. Finally, exogenous administration of DHEA reduced cancellous bone osteopenia in oophorectomized rats [42].…”

Section: Discussionmentioning

confidence: 98%

Carnitine and Dehydroepiandrosterone Sulfate Induce Protein Synthesis in Porcine Primary Osteoblast-Like Cells

et al. 1999

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Abstract. Age-related bone loss eventually leads to osteopenia in men and women. The etiology of age-related bone loss is currently unknown; however, decreased osteoblast activity contributes to this phenomenon. In turn, osteoblast proliferation and function is dependent on energy production, thus the loss of energy production that occurs with age may account for the deficient osteoblast activity. Carnitine and dehydroepiandrosterone-sulfate (DHEAS), both of which decline with age, promote energy production through fatty acid metabolism. Thus, we hypothesized that carnitine and DHEAS would increase osteoblast activity in vitro. Accordingly, we measured the effect of carnitine and DHEAS on palmitic acid oxidation as a measure of energy production, and alkaline phosphatase (ALP) activity and collagen type I (COL) as indices of osteoblast function in primary porcine osteoblast-like cell cultures. Carnitine (10 −3 and 10 −1 M) but not DHEAS (10 −9 , 10 −8 , and 10 −7 M) increased carnitine levels within the cells. Carnitine alone and in combination with DHEAS increased palmitic acid oxidation. Both carnitine and DHEAS alone and in an additive fashion increased ALP activity and COL levels. These results demonstrate that in osteoblast-like cells in vitro, energy production can be increased by carnitine and osteoblast protein production can be increased by both carnitine and DHEAS. These data suggest that carnitine and DHEAS supplementation in the elderly may stimulate osteoblast activity and decrease age-related bone loss. Key words:Osteoblast -Carnitine -Dehydroepiandrosterone sulfate -Alkaline phosphatase -Collagen Type I.Bone loss is often divided into two broad mechanisms: (1) postmenopausal bone loss, characterized by increased osteoclast activity, and (2) age-related bone loss, characterized by decreased osteoblast activity. Osteoblast activity is dependent on energy production. Thus, it is plausible that the loss of energy production, which accompanies age, may account for decreased osteoblast activity. Most cells use both glucose and fatty acid oxidation pathways for ATP synthesis, although some cell types show a substrate preference. For instance, some studies have suggested that glucose is the major fuel substrate for bone [1,2]. However, more recent work indicates that cell populations enriched with osteoblast-like cells generate 40-80% of the energy demands through fatty acid oxidation [3]. Osteoblasts are responsible for bone formation and it follows that they maintain a high rate of ATP utilization to support the requisite protein synthesis. Cells with a high rate of protein synthesis generate ATP from fatty acid oxidation, the most efficient metabolic process for energy production [4][5][6]. Thus, modulation of fatty acid oxidation may regulate the amount of energy available for protein synthesis in osteoblasts.A number of factors are required for fatty acid oxidation. For example, carnitine is the requisite carrier for the transport of long-chain fatty acids across the inner mitochondrial membrane into...

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Section: Discussionmentioning

confidence: 98%

Carnitine and Dehydroepiandrosterone Sulfate Induce Protein Synthesis in Porcine Primary Osteoblast-Like Cells

et al. 1999

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“…Decrease in bone mass induces osteoporosis, which is widely recognized as a major public health problem. The most dramatic expression of this disease is represented by fracture of the proximal femur (1)(2)(3). Decrease in bone mass is due to increased bone resorption and reduced bone formation.…”

Section: Introductionmentioning

confidence: 99%

Genistein and zinc synergistically enhance gene expression and mineralization in osteoblastic MC3T3-E1 cells

Uchiyama

Yamaguchi²

2007

Int J Mol Med

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“…Bone loss with aging induces osteoporosis, which is widely recognized as a major public health problem (1)(2)(3). The decrease in bone mass leads to bone fracture.…”

Section: Introductionmentioning

confidence: 99%

Oral administration of β-cryptoxanthin prevents bone loss in ovariectomized rats

Uchiyama

Yamaguchi²

2006

Int J Mol Med

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Abstract. The effect of ß-cryptoxanthin, a kind of carotenoid, on ovariectomy-induced bone loss was investigated. ß-Cryptoxanthin was isolated from Satsuma mandarin (Citrus unshu. MARC). ß-cryptoxanthin (5 or 10 μg/100 g body weight) was orally administered once daily for 3 months to ovariectomized (OVX) rats. OVX induced a significant increase in body weight and a significant decrease in serum calcium and inorganic phosphorus concentrations as compared with those of shamoperated (control) rats. These alterations induced by OVX were significantly prevented by the administration of ß-cryptoxanthin (5 or 10 μg/100 g). The analysis using a peripheral quantitative computed tomography (pQCT) showed that OVX induced a significant decrease in mineral content and mineral density in the femoral-diaphyseal and -metaphyseal tissues and polar strength strain index in the metaphyseal tissues. These decreases were significantly prevented by the administration of ß-cryptoxanthin (5 or 10 μg/100 g). Moreover, OVX induced a significant decrease in calcium content and alkaline phosphatase activity in the femoraldiaphyseal and -metaphyseal tissues and deoxyribonucleic acid (DNA) content in the metaphyseal tissues. These decreases were significantly prevented by the administration of ß-cryptoxanthin (5 or 10 μg/100 g). This study demonstrates that ß-cryptoxanthin has a preventive effect on OVX-induced bone loss in vivo.

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Declining Adrenal Androgens: An Association with Bone Loss in Aging Women

Cited by 99 publications

References 23 publications

Carnitine and Dehydroepiandrosterone Sulfate Induce Protein Synthesis in Porcine Primary Osteoblast-Like Cells

Carnitine and Dehydroepiandrosterone Sulfate Induce Protein Synthesis in Porcine Primary Osteoblast-Like Cells

Genistein and zinc synergistically enhance gene expression and mineralization in osteoblastic MC3T3-E1 cells

Oral administration of β-cryptoxanthin prevents bone loss in ovariectomized rats

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