Effects of Ginkgo biloba extract on glucose transport and glycogen synthesis of cultured smooth muscle cells from pig aorta.
We have examined the effect of an extract of Ginkgo biloba (Gbe) on glucose uptake and on glycogen synthesis in cultured smooth muscle cells (SMC) from pig aorta. Initial rates of glucose transport were determined by measurements of 2-deoxy-D-glucose (2-DG) uptake. From kinetic analyses apparent KM and Vmax values of facilitated glucose transport in cultured SMC were evaluated at 2.2 mM and 9.1 nmol/min/10(6) cells respectively. Gbe stimulated glucose transport in a dose-dependent manner; the maximum effect was reached at a Gbe concentration of 0.25 micrograms/ml and represented an increase of 35 +/- 4% above basal activity. This stimulation mainly occurred on facilitated glucose transport. The passive diffusion measured when cells were treated with cytochalasin B represented 15 +/- 3% of glucose total transport activity either in the absence or the presence of Gbe. The effect of Gbe on glycogen synthesis in cultured SMC was then tested by the incorporation of U14C-glucose into cellular glycogen. This process was enhanced by Gbe, the maximal effect was observed at a Gbe concentration of 0.25 micrograms/ml, and represented a 41 +r4% increase above basal activity. These data argue for a direct effect of Gbe upon glucose transport and glucose utilization in cultured SMC thus allowing a better nutriment disposal in the vascular wall.
Laboratoire de Biochimie INSERM U 181, Faculté de Médecine Saint-Antoine, Paris, France.
A
A
Bruel
J
J
Gardette
E
E
Berrou
M T
MT
Droy-Lefaix
J
J
Picard
D000818:Animals; D001011:Aorta / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D001692:Biological Transport / Q000187:drug effects; D002478:Cells, Cultured; D005947:Glucose / Q000378:metabolism*; D006003:Glycogen / Q000096:biosynthesis*; D009131:Muscle, Smooth, Vascular / Q000166:cytology / Q000187:drug effects* / Q000378:metabolism; D010936:Plant Extracts / Q000494:pharmacology*; D013552:Swine; D014197:Trees
D010936:Plant Extracts; D006003:Glycogen; D005947:Glucose