Short-term ingestion of Ginkgo biloba extract does not alter whole body insulin sensitivity in non-diabetic, pre-diabetic or type 2 diabetic subjects--a randomized double-blind placebo-controlled crossover study.
OBJECTIVE
Ingestion of Ginkgo biloba Extract (EGb 761) may increase pancreatic beta-cell function in both healthy subjects with normal glucose tolerance (NGT) as well as patients with Type 2 Diabetes mellitus (T2DM). Since hyperinsulinemia is a hallmark of T2DM, it is important to verify that increased insulin production is not due to increased insulin resistance.


METHODS
NGT subjects (n = 10; age, 44.2 +/- 13.9 years old), impaired glucose tolerance (IGT) (n = 8; age 51.3 +/- 6.6 years old) and T2DM subjects (n = 8, 51.6 +/- 15.2 years old) completed a randomized, double-blind, placebo-controlled crossover study. After ingesting either EGb 761 (120 mg/day as a single dose) or placebo during each 3-month arm, a 2-step euglycemic insulin clamp was performed.


RESULTS
At the low insulin infusion rate (10 mU/m2/min) the glucose metabolic rates (M values) were 3.5 +/- 1.5 vs. 3.0 +/- 0.5 mg/kg (P = 0.16), 3.0 +/- 0.4 vs. 2.8 +/- 0.8 mg/kg (P = 0.19) and 2.6 +/- 0.7 vs. 2.4 +/- 0.5 mg/kg (P = 0.09) for the placebo and EGb 761 cycles, in the NGT, IGT and T2DM subjects, respectively. At the high insulin infusion rate (40 mU/m2/min) the M values were 7.3+/-2.3 vs. 8.1 +/- 2.5mg/kg (P = 0.07), 6.2 +/- 1.6 vs. 6.5 +/- 2.1 mg/kg (P = 0.32) and 3.6 +/- 1.6 vs. 3.5 +/- 1.0 mg/kg (P = 0.34) for placebo vs. EGb 761 cycles, in the NGT, IGT and T2DM subjects, respectively.


CONCLUSIONS
The ingestion of 120 mg of EGb 761 as a single for 3 months did not produce insulin resistance in the non-diabetic or pre-diabetic subjects or exacerbate the disease in the T2DM subjects.
Kudolo
George B
GB
Department of Clinical Laboratory Sciences, University of Texas Health Science Center at San Antonio, 7703 Floyd Curl Drive, San Antonio, Texas 78229-3900, USA. Kudolo@uthscsa.edu
Wang
Wen
W
Elrod
Ryan
R
Barrientos
Jessica
J
Haase
Alexis
A
Blodgett
Janet
J
D000328:Adult; D001786:Blood Glucose / Q000378:metabolism*; D018592:Cross-Over Studies; D003924:Diabetes Mellitus, Type 2 / Q000188:drug therapy / Q000378:metabolism*; D004311:Double-Blind Method; D005260:Female; D020441:Ginkgo biloba; D015309:Glucose Clamp Technique; D006801:Humans; D007328:Insulin / Q000378:metabolism*; D007333:Insulin Resistance; D050417:Insulin-Secreting Cells / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008875:Middle Aged; D010936:Plant Extracts / Q000494:pharmacology*; D000096983:Ginkgo Extract
D001786:Blood Glucose; D007328:Insulin; D010936:Plant Extracts; C063170:Ginkgo biloba extract; D000096983:Ginkgo Extract