1,25(OH)2D3 increases calcium and phosphatidylinositol metabolism in differentiating cultured human keratinocytes
| Autor: | Lewis C. Cantley, Julia A. MacLaughlin, Michael F. Holick |
|---|---|
| Rok vydání: | 1990 |
| Předmět: |
medicine.medical_specialty
Nutrition and Dietetics Calcitriol Endocrinology Diabetes and Metabolism Clinical Biochemistry chemistry.chemical_element Biology Calcium Biochemistry Calcium in biology chemistry.chemical_compound EGTA Endocrinology chemistry Internal medicine medicine Lysophosphatidylinositol Phosphatidylinositol Cholecalciferol Molecular Biology Incubation medicine.drug |
| Zdroj: | The Journal of Nutritional Biochemistry. 1:81-87 |
| ISSN: | 0955-2863 |
| DOI: | 10.1016/0955-2863(90)90054-o |
| Popis: | The effect of 1,25(OH) 2 D 3 on the intracellular calcium, (Ca +2 )i, in both cultured human keratinocytes and in cultured human dermal fibroblasts was investigated. When the intracellular calcium (Ca +2 )i in cultured human keratinocytes, grown in a serum-free medium containing 1.8 m M calcium, was measured by the fluorescent calcium-indicator, Furu-2, the (Ca +2 i increased 154%, 202%, and 409% over the control value after incubation with 1,25(OH) 2 D 3 at 10 −10 m , 10 −8 m , and 10 −6 m , respectively. This response was immediate (15 seconds), specific (no effect with either 25(OH)D 3 at 10 −8 m or vitamin D 3 at 10 −8 m ), and occurred with or without EGTA in the medium. In contrast, 1,25(OH) 2 D 3 did not increase the (Ca 2+ )i in either cultured human keratinocytes that were grown in low calcium (0.05 m m ), serum-free medium or in cultured human dermal fibroblasts that were grown in medium containing 0.05 m m calcium and 1% serum. The effect of 1,25(OH) 2 D 3 on the the turnover of phosphatidylinositol was investigated as a possible cause for the observed increase in (Ca +2 i. Cultured human keratinocytes that were incubated with 3 H-inositol demonstrated a 50% ± 10% increase in the triphosphated, plasma membrane-bound metabolite of phosphatidylinositol, PIP 2 , by 15 seconds, followed by a rapid decrease at 30 seconds, then a return toward basal levels by 1 minute. Lysophosphatidylinositol, which results from the sn-2 deacylation of phosphatidylinositol by phospholipase A 2 , decreased 20% ± 8% within 30 seconds, then increased to 200% ± 10% of the control value by 5 minutes. The accumulation of IP 3 was increased 50% to 100% above the control value within 30 seconds and this increase was substained during the 5-minute incubation period. Stimulation of phosphatidylinositol turnover by 1,25(OH) 2 D 3 was not detected in either cultured human keratinocytes that were grown in serum-free, low calcium medium or in cultured human dermal fibroblasts that were grown in 1% serum. |
| Databáze: | OpenAIRE |
| Externí odkaz: |
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