75.有關P-glycoprotein的敘述，下列何者正確？
(A)是一個transporter，將藥品由細胞外往細胞內運送
(B)對於以高劑量在腸胃道作用的藥品影響較大
(C)對於以微小劑量經腸胃道吸收的藥品影響較大
(D)因P-glycoprotein受質之特異性與CYP2D6相近，誘導劑與抑制劑也都與CYP2D6相同

P-gp is extensively distributed and expressed in the intestinal epithelium where it pumps xenobiotics (such as toxins or drugs) back into the intestinal lumen, in liver cells where it pumps them into bile ducts, in the cells of the proximal tubule of the kidney where it pumps them into urinary filtrate (in the proximal tubule), and in the capillary endothelial cells composing the blood–brain barrier and blood–testis barrier, where it pumps them back into the capillaries.

P-gp分布在腸上皮，負責將物質外排出去，所以會影響到的是 在"腸"吸收的藥物，與在腸胃道作用的藥物關係較小

(B) 對於以高劑量在腸胃道作用的藥品影響較大

(C) 對於以微小劑量經腸胃道吸收的藥品影響較大

高劑量跟微小劑量應該是為了誤導我們作答，感覺這題是文字遊戲 ??
有錯歡迎大大們更正~~