Retinol-binding protein secretion from the liver of N-(4-hydroxyphenyl) retinamide-treated rats.
N-(4-Hydroxyphenyl)retinamide (HPR; Fenretinide), a synthetic retinoid possessing antitumor activity, depresses plasma retinol and retinol-binding protein (RBP) concentrations. In study 1, the ability of retinol or HPR to induce RBP secretion from the livers of vitamin A-deficient rats was compared. A large apoRBP pool accumulated in the liver rough microsomes of these rats. Following retinol repletion, 80% of the accumulated RBP was rapidly secreted into the plasma. In contrast, HPR treatment only induced two-thirds of the RBP secretion observed with retinol. Prior colchicine treatment caused a large RBP accumulation in the Golgi-enriched fraction following retinol repletion. HPR plus colchicine treatment produced significantly less accumulation of RBP in the Golgi-enriched fraction than did retinol. In study 2, HPR treatment of vitamin A-adequate rats caused RBP to accumulate in the liver rough microsomes. When vitamin A-adequate rats were treated with colchicine, the concentration of RBP in the Golgi-enriched fraction increased 2.9-fold. However, significantly less RBP accumulated in the Golgi following HPR treatment. These studies demonstrate that HPR will induce liver RBP secretion, but to a lesser degree than retinol. Further, more RBP remained in the rough microsomes of HPR treated, vitamin A-adequate rats, indicating that HPR depressed the amount of RBP secreted.
Ritter
S J
SJ
Nutrition Department, Pennsylvania State University, University Park 16802-6504, USA.
Smith
J E
JE
D000818:Animals; D000970:Antineoplastic Agents / Q000494:pharmacology*; D001692:Biological Transport; D002451:Cell Compartmentation; D003078:Colchicine / Q000494:pharmacology; D017313:Fenretinide / Q000494:pharmacology*; D008099:Liver / Q000378:metabolism*; D008297:Male; D011228:Prealbumin / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D012177:Retinol-Binding Proteins / Q000378:metabolism*; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A / Q000097:blood; D014802:Vitamin A Deficiency / Q000378:metabolism
D000970:Antineoplastic Agents; D011228:Prealbumin; D012177:Retinol-Binding Proteins; D054839:Retinol-Binding Proteins, Plasma; D014801:Vitamin A; D017313:Fenretinide; D003078:Colchicine