Acute effects of insulin on glycerol phosphate acyl transferase activity, ketogenesis and serum free fatty acid concentration in perfused rat liver

A selective decrease in mitochondrial glycerol phosphate acyltransferase activity in livers from streptozotocin‐diabetic rats

“…Whether the decrease in mitochondrial GPAT reflects an acute regulatory response or some gross change in amount of enzyme protein is unclear at present. The effect of insulin on GPAT activity in perfused rat liver seen in the accompanying paper [3] however suggests that acute regulation by insulin may occur. A mitochondrial GPAT activity varying in response to insulin is obviously of relevance to interrelated control of fatty acid esterification and oxidation.…”

“…It is noteworthy that the very different responses seen with thiol reagents [3,15,16] could suggest that the mitochondri',,t and microsomal GPAT activities reside in different enzymes. Whether the decrease in mitochondrial GPAT reflects an acute regulatory response or some gross change in amount of enzyme protein is unclear at present.…”

“…In order to establish a basis for studies of short-term insulin action on hepatic GPAT in the intact animal the effect of mild diabetes on the mitochondrial and microsomal enzymes has been investigated. Effects of insulin on GPAT in the perfused rat liver are presented [3]. A statistically inconclusive study of the effect of starvation on hepatic GPAT has been made [4], but there do not appear to be any previous reports of the effect of diabetes.…”

Role of insulin in hepatic fatty acid partitioning: emerging concepts

“…Thus it is specifically the activity of mitochondrial GPAT that is decreased in the diabetic-or starved-rat liver [11,12]. Moreover, insulin acutely increases mitochondrial GPAT activity in the perfused rat liver [13]. This effect is analogous to the effect of insulin on cardiomyocyte and adipocyte GPAT [14,15].…”

The malonyl-CoA–long-chain acyl-CoA axis in the maintenance of mammalian cell function

“…In particular, it is the activity of mitochondrial GPAT that undergoes variation with physiological state, e.g. it is diminished in the liver of diabetic or starved rats [106,107] and is acutely activated by insulin in the perfused liver [108]. By contrast, insulin increases the sensitivity of mitochondrial CPTo to malonyl-CoA inhibition [109] and decreases transcription of the CPTo gene in H411E cells [109].…”