Whitehurst G B, Beitz D C, Cianzio D, Topel D G
J Nutr. 1981 Aug;111(8):1454-61. doi: 10.1093/jn/111.8.1454.
Rates of fatty acid synthesis from lactate and acetate and activities of selected lipogenic and NADPH-generating enzymes were determined in subcutaneous, intermuscular and intramuscular adipose tissues of cattle that were 11-19 months of age. Fatty acid synthesis from lactate and acetate increased from 11 to 13 months of age in subcutaneous and intermuscular adipose tissues; synthesis from lactate increased until 17 months of age. In intramuscular adipose tissue, synthesis from lactate also increased until 17 months of age while that from acetate continually increased. Activities of NADPH-generating enzymes increased in all three fat depots from 11 to 13 months of age, and little change occurred thereafter. Acetyl-CoA carboxylase activity was constant over entire growth period in all depots. Activity of ATP-citrate lyase increased from 11 to 13 months of age in subcutaneous and intermuscular adipose tissues, but did not increase until 19 months of age in intramuscular adipose tissue. In all cases, activities of ATP-citrate lyase were sufficient to support synthesis from lactate; therefore, lactate conversion to fatty acids in bovine adipose tissues seems to use the citrate cleavage pathway for generation of cytosolic acetyl-CoA.
在11至19月龄的牛的皮下、肌间和肌内脂肪组织中，测定了由乳酸和乙酸合成脂肪酸的速率以及选定的生脂酶和生成NADPH的酶的活性。皮下和肌间脂肪组织中，由乳酸和乙酸合成脂肪酸的速率在11至13月龄时增加；由乳酸合成脂肪酸的速率一直增加到17月龄。在肌内脂肪组织中，由乳酸合成脂肪酸的速率也一直增加到17月龄，而由乙酸合成脂肪酸的速率则持续增加。所有三个脂肪库中，生成NADPH的酶的活性在11至13月龄时增加，此后变化不大。所有脂肪库中，乙酰辅酶A羧化酶的活性在整个生长期间保持恒定。皮下和肌间脂肪组织中，ATP柠檬酸裂解酶的活性在11至13月龄时增加，但肌内脂肪组织中直到19月龄时才增加。在所有情况下，ATP柠檬酸裂解酶的活性足以支持由乳酸合成脂肪酸；因此，牛脂肪组织中乳酸转化为脂肪酸似乎利用柠檬酸裂解途径来生成胞质乙酰辅酶A。
