Relation between insulin kinetics and insulin sensitivity in pregnancy.
BACKGROUND
Different time-concentration profiles of plasma insulin following insulin modification of a frequently sampled intravenous glucose-tolerance-test (FSIVGTT) were observed in a study investigating maternal metabolism and fetal macrosomia. We aimed to investigate whether these differences were related to the volume of distribution of insulin, insulin clearance, or both.


METHODS
Forty-four women were studied between 33 and 35 weeks' gestation using an insulin-modified FSIVGTT. Specific insulin was assayed with an enzyme-linked immunosorbent assay. Insulin sensitivity was calculated using the minimal model and the homeostasis model assessment (HOMA). The volume of distribution and clearance of insulin were calculated from measurements between 2 and 155 min after insulin modification using a one-compartment model.


RESULTS
In accordance with the method for deriving the volume of distribution, there was a significant negative correlation between the increment in insulin concentration and the volume of distribution (rho=-0.92, P<0.0001). The insulin increment was also related negatively to the clearance of insulin (rho=-0.88, P<0.0001). There was a significant correlation between the volume of distribution and both the insulin sensitivity index (rho=0.56, P<0.0001) and HOMA-%S (rho=0.30, P=0.048), and between the clearance of insulin and both the insulin sensitivity index (rho=0.83, P<0.0001)) and HOMA-%S (rho=0.34, P=0.025).


CONCLUSIONS
The different time-concentration profiles of plasma insulin resulted from differences in the volume of distribution and clearance of insulin. There was a correlation between insulin kinetics and the insulin sensitivity index. Further research is required to investigate possible mechanisms by which insulin kinetics may be related to insulin sensitivity.
Jolly
M C
MC
Section of Endrocrinology and Metabolic Medicine, Imperial College London, St Mary's Campus, London, UK.
Hovorka
R
R
Godsland
I
I
Amin
R
R
Lawrence
N
N
Anyaoku
V
V
Johnston
D
D
Robinson
S
S
D004797:Enzyme-Linked Immunosorbent Assay / Q000379:methods; D005260:Female; D005951:Glucose Tolerance Test / Q000379:methods; D006706:Homeostasis / Q000502:physiology; D006801:Humans; D007328:Insulin / Q000097:blood*; D007333:Insulin Resistance / Q000502:physiology*; D011247:Pregnancy / Q000502:physiology*; D012044:Regression Analysis
D007328:Insulin