TABLE 5

Muscle membrane Mg2+-dependent neutral sphingomyelinase and lysosomal Zn2+-independent acid sphingomyelinase activities and sphingosine and sphinganine content at baseline, after 4-h hyperinsulinemia, and after clamp with Intralipid/heparin infusion (n = 10)

BaselineAfter 4-h clampAfter 4-h clamp with Intralipid/heparin infusion
101010
Neutral sphingomyelinase (nmol of ceramide · h−1 · mg of protein−1)0.53 ± 0.180.44 ± 0.160.48 ± 0.14
Acid sphingomyelinase (nmol of ceramide · h−1 · mg of protein−1)2.92 ± 0.403.01 ± 0.683.45 ± 0.57*
Sphingosine (nmol/g tissue)0.95 ± 0.160.98 ± 0.121.08 ± 0.15
Sphinganine (nmol/g tissue)0.31 ± 0.060.30 ± 0.080.35 ± 0.04*
  • Data are expressed as means ± SD

  • *

    * P < 0.05 in comparison to baseline values.