Tamoxifen might influence the affinity of LPL for heparin-sepharose.
BACKGROUND
We previously reported that the tamoxifen treatment caused a decrease in lipoprotein lipase (LPL) activity and an increase in LPL mass. We hypothesized that tamoxifen may increase the quantity of inactive LPL.


METHODS
Lipoprotein lipase in post-heparin plasma usually exists in both monomeric and dimeric forms, which may be separated on a heparin-Sepharose column with different salt concentrations. Lipoprotein lipase in post-heparin plasma from postmenopausal patients with hypertriglyceridemia treated with or without tamoxifen was incubated with or without 4-hydroxy-tamoxifen (4-OHT), the monomers and dimers were separated on a heparin-Sepharose column and their masses were measured.


RESULTS
The masses of total LPL and dimeric LPL of tamoxifen-treated patients were significantly higher than those of control subjects. Monomeric LPL of tamoxifen-treated patients passed more slowly through the heparin-Sepharose column compared with that of control subjects. The ratio of monomeric LPL to dimeric LPL of tamoxifen-treated patients was 0.61, significantly lower than that of control subjects, which was 1.45 (p<0.01). In addition, monomeric LPL incubated with 4-OHT passed more slowly through the heparin-Sepharose column compared with that incubated without 4-OHT.


CONCLUSIONS
Tamoxifen influences the affinity of LPL for heparin.
Kawano
Mikihiko
M
Department of Clinical Laboratory Medicine, Jichi Medical School, 3311-1 Yakushiji, Minamikawachi-machi, Kawachi-gun, Tochigi 329-0498, Japan. mkkawano@jichi.ac.jp
Hozumi
Yasuo
Y
Itoh
Kouichi
K
D001943:Breast Neoplasms / Q000097:blood / Q000188:drug therapy; D002784:Cholesterol / Q000097:blood; D002847:Chromatography, Agarose; D004965:Estrogen Antagonists / Q000737:chemistry* / Q000494:pharmacology; D005260:Female; D006493:Heparin / Q000494:pharmacology; D006801:Humans; D006953:Hyperlipoproteinemia Type IV / Q000097:blood; D008071:Lipoprotein Lipase / Q000097:blood / Q000737:chemistry* / Q000187:drug effects; D017698:Postmenopause / Q000097:blood; D012685:Sepharose / Q000031:analogs & derivatives* / Q000737:chemistry*; D013629:Tamoxifen / Q000031:analogs & derivatives* / Q000737:chemistry* / Q000494:pharmacology; D014280:Triglycerides / Q000097:blood
D004965:Estrogen Antagonists; D014280:Triglycerides; C037405:heparin-sepharose; D013629:Tamoxifen; C016601:afimoxifene; D006493:Heparin; D012685:Sepharose; D002784:Cholesterol; D008071:Lipoprotein Lipase