Young A J, Schmotzer W B, Swanson L V
Department of Animal Science, College of Veterinary Medicine, Oregon State University, Corvallis 97331.
Proc Soc Exp Biol Med. 1990 Apr;193(4):274-9. doi: 10.3181/00379727-193-43035.
An in vitro study was conducted to determine whether bovine mammary glucose-6-phosphate dehydrogenase (G6PD) activity was regulated by palmitoyl coenzyme A (CoA), acetate, spermidine, and putrescine and whether these effects were dependent upon stage of lactation. Early lactation explants incubated in media containing palmitoyl CoA or acetate had reduced (P less than 0.01) G6PD activity compared with incubated control explants. G6PD activity in early lactation explants was reduced (P less than 0.05) when incubated with 5 microM palmitoyl CoA or 1 mM acetate compared with 25 microM palmitoyl CoA or 10 mM acetate. Spermidine (0.4 mM) reversed (P less than 0.05) palmitoyl CoA-induced inhibition of early lactation G6PD activity at 5 microM, but not at 25 microM palmitoyl CoA. G6PD activity in early lactation explants was decreased (P less than 0.05) when treated with putrescine (0.4 mM) compared with explants treated with spermidine. Addition of acetate in combination with 5 microM palmitoyl CoA reversed G6PD inhibition (P less than 0.05 for 1 mM and P less than 0.01 for 10 mM) while addition of either level of acetate in combination with 25 microM palmitoyl CoA failed to reverse G6PD inhibition. G6PD activity was higher (P less than 0.01) in early lactation than mid-lactation explants. No statistical differences (P greater than 0.1) were found among any treatments in explants from mid-lactation cows. We conclude that palmitoyl CoA and acetate will inhibit G6PD activity in early lactation, but not mid-lactation explants; addition of spermidine will reverse this inhibition.
进行了一项体外研究，以确定牛乳腺葡萄糖-6-磷酸脱氢酶（G6PD）的活性是否受棕榈酰辅酶A（CoA）、乙酸盐、亚精胺和腐胺的调节，以及这些影响是否取决于泌乳阶段。与培养的对照外植体相比，在含有棕榈酰CoA或乙酸盐的培养基中培养的早期泌乳外植体的G6PD活性降低（P<0.01）。与25 microM棕榈酰CoA或10 mM乙酸盐相比，早期泌乳外植体在与5 microM棕榈酰CoA或1 mM乙酸盐一起培养时，G6PD活性降低（P<0.05）。亚精胺（0.4 mM）可逆转（P<0.05）5 microM棕榈酰CoA诱导的早期泌乳G6PD活性抑制，但不能逆转25 microM棕榈酰CoA诱导的抑制。与用亚精胺处理的外植体相比，用腐胺（0.4 mM）处理的早期泌乳外植体的G6PD活性降低（P<0.05）。乙酸盐与5 microM棕榈酰CoA联合添加可逆转G6PD抑制（1 mM时P<0.05，10 mM时P<0.01），而乙酸盐与25 microM棕榈酰CoA联合添加的任何水平均未能逆转G6PD抑制。早期泌乳外植体的G6PD活性高于中期泌乳外植体（P<0.01）。在中期泌乳奶牛的外植体中，任何处理之间均未发现统计学差异（P>0.1）。我们得出结论，棕榈酰CoA和乙酸盐会抑制早期泌乳外植体中的G6PD活性，但不会抑制中期泌乳外植体中的活性；添加亚精胺可逆转这种抑制作用。
