Premium
Rapid actions of 1α,25‐dihydroxyvitamin D 3 on Ca 2+ and phospholipids in isolated rat liver nuclei
Author(s) -
Baran Daniel T.,
Sorensen Ann M.,
Honeymano Thomas W.,
Ray Rahul,
Holick Michael F.
Publication year - 1989
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(89)81529-7
Subject(s) - phosphatidylinositol , phospholipid , chemistry , metabolism , incubation , alpha (finance) , biochemistry , membrane , signal transduction , medicine , construct validity , nursing , patient satisfaction
The effects of 1α,25‐dihydroxyvitamin D 3 (1α,25‐(OH) 2 D 3 ) on Ca 2+ levels and phospholipid metabolism were studied in isolated nuclei prepared from rat liver. Nuclear Ca 2+ concentration was estimated with the fluorescent indicator Fura 2. In agreement with previous reports, ATP (1 mM) produced a rapid increase in nuclear Ca 2+ from 188 ±25 to 593 ±121 nM. Exposure to 1α,25‐(OH) 2 D 3 (20 nM) also produced a rapid increase in nuclear Ca 2+ to 402±71 nM. The 1β epimer of lα,25‐(OH) 2 D 3 had no effect. Nuclear phosphatidylinositol was labeled by incubation with [γ‐ 32 p]ATP for 3 h. 1α,25‐(OH) 2 D 3 produced a two‐fold increase in [ 32 P]lysophosphatidylinositol (LPI) within 5 min from 44 ± 11 to 87 ± 19 cpm/2.5 × 10 7 nuclei. 1β,25‐(OH) 2 D 3 had no effect on [su32P]LPI production. Exposure of nuclei to exogenous LPI (15μM) produced an instantaneous increase in nuclear Ca 2+ to 372±81 nM, comparable to ATP and lα,25‐(OH) 2 D 3 . The rapid effects of 1α,25‐(OH) 2 D 3 on phospholipid metabolism and Ca 2+ in isolated nuclei suggest that the steroid may exert effects distinct from the well‐characterized receptor‐mediated changes in gene expression.