Paglia D E
Department of Pathology and Laboratory Medicine, UCLA School of Medicine, University of California 90024.
Am J Hematol. 1993 Jan;42(1):36-45. doi: 10.1002/ajh.2830420109.
Sudden episodes of massive hemolysis have become the most common cause of death among captive black rhinoceroses, and there is evidence that they occur in the wild as well. We have observed radically unique enzyme and metabolite profiles in normal rhinoceros erythrocytes compared to humans and other mammals, including marked deficiencies of intracellular adenosine triphosphate (ATP), catalase, adenosine deaminase, and other enzymes involved in glycolysis, glutathione cycling, and nucleotide metabolism. Minimal concentrations of ATP appear to impair effective acceleration of hexosemonophosphate shunt activity in response to oxidants by restricting substrate generation at the hexokinase step. Antioxidant defenses are further compromised by catalase deficiency, which may be a general characteristic of rhinoceros erythrocytes, perhaps related to the common occurrence of severe mucocutaneous ulcerative disease. It is proposed that erythrocyte ATP deficiency in rhinoceroses may be an evolutionary adaptation conferring selective advantage against common hemic parasites, comparable to the role of human glucose-6-phosphate dehydrogenase (G-6-PD) deficiency in falciparum malaria.
大规模溶血的突发情况已成为圈养黑犀牛中最常见的死亡原因，并且有证据表明它们在野外也会发生。与人类和其他哺乳动物相比，我们在正常犀牛红细胞中观察到了截然不同的酶和代谢物谱，包括细胞内三磷酸腺苷（ATP）、过氧化氢酶、腺苷脱氨酶以及其他参与糖酵解、谷胱甘肽循环和核苷酸代谢的酶显著缺乏。ATP的最低浓度似乎通过限制己糖激酶步骤中的底物生成，损害了对氧化剂的磷酸己糖旁路活性的有效加速。过氧化氢酶缺乏进一步损害了抗氧化防御，这可能是犀牛红细胞的一个普遍特征，也许与严重的黏膜皮肤溃疡性疾病的常见发生有关。有人提出，犀牛红细胞中的ATP缺乏可能是一种进化适应，赋予了对常见血液寄生虫的选择性优势，类似于人类葡萄糖-6-磷酸脱氢酶（G-6-PD）缺乏在恶性疟疾中的作用。
