TY - JOUR
T1 - Vitamin D metabolites stimulate phosphatidylcholine transfer to renal brush-border membranes
AU - Kurnik, Brenda R.C.
AU - Huskey, Margaret
AU - Hagerty, David
AU - Hruska, Keith A.
N1 - Funding Information:
The authors thank the Diabetes Research Center for preparation of electron micrographs. M.H. for her technical assistance, and Karon Farris and Helen Odle for their secretarial assistance. This work was supported by NIH Grant AM32087 and funds from The Jewish Hospital of St. Louis. K.A.H. is an Established Investigator of the American Heart Association. A patent application has been filled and is pending, entitled 'Direct transfer of membrane lipids from one membrane to another'.
PY - 1986/6/13
Y1 - 1986/6/13
N2 - The phosphatidylcholine content of both the intestinal and renal brush-border membranes and ion transport are affected by 1,25-dihydroxycholecalciferol (1,25(OH)2D3). To investigate the mechanism of this effect, liposomes were prepared containing self-quenching concentrations of fluorescent phospholipid derivatives. When these liposomes were incubated with rat renal brush-border membrane vesicles, an immediate increase in the relative fluorescence of N-4-nitrobenz-2-oxa-1,3-diazole phosphatidylcholine (NBD-PC) was detected, indicating transfer of NBD-PC into a non-quenched membrane. Addition of 1,25(OH)2D3 to the liposomes produced a dose-dependent stimulation of NBD-PC transfer to the acceptor brush-border membrane vesicles. Peripheral fluorescence was visible when the brush-border membrane vesicles were viewed with a fluorescent microscope. Using brush-border membrane vesicles from kidneys of vitamin D-deficient animals, quantitation of lipid transfer revealed a 1,25(OH)2D3 (10-7 M) stimulation of NBD-PC transfer from 1.38 ± 0.27 to 2.07 ± 0.26 μg/h, and of PC transfer, assessed by vesicle phosphatidylcholine content, from 49.7 ± 12 to 57.3 ± 12 μg/mg protein per h (P < 0.05). There was no significant transfer of N-(lissamine rhodamine B sulfonyl)dioleoylphosphatidylethanolamine (N-Rh-PE). In the absence of hormone, the amount of NBD-PC transferred to brush-border membrane vesicles prepared from normal rats was significantly greater than that transferred to brush-border membrane vesicles prepared from vitamin D-deficient animals (2.12 ± 0.02 vs. 1.39 ± 0.27 μg of NBD-PC/h, P < 0.05). Both physiologic and pharmacologic concentrations of 1,25(OH)2D3 stimulated NBD-PC transfer with maximum response at 10-14 M (2.98 ± 0.15 μg/h). 24,25-Dihydroxycholecalciferol and 25-hydroxycholecalciferol (25(OH)D3) also stimulated transfer, although dose-response curves were less effective than for 1,25(OH)2D3. Cortisol and vitamin D-3 did not stimulate transfer. 1,25(OH)2D3 did not stimulate NBD-PC transfer between liposome populations.
AB - The phosphatidylcholine content of both the intestinal and renal brush-border membranes and ion transport are affected by 1,25-dihydroxycholecalciferol (1,25(OH)2D3). To investigate the mechanism of this effect, liposomes were prepared containing self-quenching concentrations of fluorescent phospholipid derivatives. When these liposomes were incubated with rat renal brush-border membrane vesicles, an immediate increase in the relative fluorescence of N-4-nitrobenz-2-oxa-1,3-diazole phosphatidylcholine (NBD-PC) was detected, indicating transfer of NBD-PC into a non-quenched membrane. Addition of 1,25(OH)2D3 to the liposomes produced a dose-dependent stimulation of NBD-PC transfer to the acceptor brush-border membrane vesicles. Peripheral fluorescence was visible when the brush-border membrane vesicles were viewed with a fluorescent microscope. Using brush-border membrane vesicles from kidneys of vitamin D-deficient animals, quantitation of lipid transfer revealed a 1,25(OH)2D3 (10-7 M) stimulation of NBD-PC transfer from 1.38 ± 0.27 to 2.07 ± 0.26 μg/h, and of PC transfer, assessed by vesicle phosphatidylcholine content, from 49.7 ± 12 to 57.3 ± 12 μg/mg protein per h (P < 0.05). There was no significant transfer of N-(lissamine rhodamine B sulfonyl)dioleoylphosphatidylethanolamine (N-Rh-PE). In the absence of hormone, the amount of NBD-PC transferred to brush-border membrane vesicles prepared from normal rats was significantly greater than that transferred to brush-border membrane vesicles prepared from vitamin D-deficient animals (2.12 ± 0.02 vs. 1.39 ± 0.27 μg of NBD-PC/h, P < 0.05). Both physiologic and pharmacologic concentrations of 1,25(OH)2D3 stimulated NBD-PC transfer with maximum response at 10-14 M (2.98 ± 0.15 μg/h). 24,25-Dihydroxycholecalciferol and 25-hydroxycholecalciferol (25(OH)D3) also stimulated transfer, although dose-response curves were less effective than for 1,25(OH)2D3. Cortisol and vitamin D-3 did not stimulate transfer. 1,25(OH)2D3 did not stimulate NBD-PC transfer between liposome populations.
KW - (Rat kidney brush-border membrane)
KW - 1,25-Dihydroxycholecalciferol
KW - Fluorescence
KW - N-4-Nitrobenz-2-oxa-1,3-diazole phosphatidylcholine
KW - Phosphatidylcholine
KW - Phospholipid transfer
KW - Vitamin D
UR - http://www.scopus.com/inward/record.url?scp=0022541260&partnerID=8YFLogxK
U2 - 10.1016/0005-2736(86)90290-7
DO - 10.1016/0005-2736(86)90290-7
M3 - Article
C2 - 3754768
AN - SCOPUS:0022541260
SN - 0005-2736
VL - 858
SP - 47
EP - 55
JO - BBA - Biomembranes
JF - BBA - Biomembranes
IS - 1
ER -