IT HAS BEEN HYPOTHESIZED THAT INSULIN LEVELS OR BRAIN INSULIN KINETICS MAY BE INVOLVED IN AN INDIVIDUALS WEIGHT SET POINT. USING A TWO COMPARTMENT MODEL (CEREBROSPINAL FLUID [CSF]) AND AN INTERMEDIATE COMPARTMENT HYPOTHESIZED TO BE BRAIN INTERSTITIAL FLUID (ISF) WITH A FORCING FUNCTION REPRESENTING PLASMA INSULIN DRIVING THE SYSTEM, CSF INSULIN DATA IN DOGS WERE FITTED TO A MODEL TO DETERMINE INSULIN TRANSPORT RATE CONSTANTS INTO THE CENTRAL NERVOUS SYSTEM. USING THE THEORY OF OPTIMAL SAMPLING DEVELOPED BY RFKA, THE RATE CONSTANTS CHARACTERIZING THE MODEL WERE DETERMINED WITH EXCELLENT PRECISION; THE RESULTS SHOWED A SATURABLE TRANSPORT SYSTEM (MANUSCRIPT PUBLISHED IN J. CLIN. INVEST.). ANOTHER SET OF EXPERIMENTS SHOWED THE SYSTEM WAS SENSITIVE TO TREATMENT WITH DEXAMETHASONE, AND THAT SUCH TREATMENT DECREASED PLASMA INSULIN UPTAKE (MANUSCRIPT SUBMITTED TO DIABETES). THE FINAL SET OF EXPERIMENTS STUDIED OBESITY, AND FOUND THAT WITH WEIGHT GAIN PLASMA INSULIN UPTAKE CHANGED INDEPENDENTLY FROM THE OTHER MODEL PARAMETERS. IT IS HYPOTHESIZED AS A RESULT OF THESE STUDIES THAT INSULIN DELIVERY TO THE CNS IS A MAJOR PREDICTOR OF FOOD INTAKE AND BODY WEIGHT GAIN DURING HIGH FAT FEEDING IN DOGS (MANUSCRIPT TO BE SUBMITTED TO SCIENCE). DR. BAURA, WHO HAS LEFT THE UNIVERSITY FOR AN INDUSTRIAL POSITION, HAS CONTINUED TO DEVELOP THE THEORY, AND HAS PROPOSED A NONINVASIVE TECHNIQUE TO MEASURE INSULIN TRANSPORT IN THE CSF IN HUMANS. A PRELIMINARY PATENT HAS BEEN OBTAINED, AND SHE IS ACTIVELY SEEKING SUPPORT FROM THE PHARMACEUTICAL INDUSTRY TO CONTINUE HER WORK. IF SUCCESSFUL, A MAJOR NEW COLLABORATIVE EFFORT WILL COMMENCE AND SAAM II WILL BE THE DATA ANALYSIS TOOL OF CHOICE.

Agency
National Institute of Health (NIH)
Institute
National Center for Research Resources (NCRR)
Type
Biotechnology Resource Grants (P41)
Project #
5P41RR002176-10
Application #
5223833
Study Section
Project Start
Project End
Budget Start
Budget End
Support Year
10
Fiscal Year
1996
Total Cost
Indirect Cost
Wolfe, B M; Barrett, P H; Laurier, L et al. (2000) Effects of continuous conjugated estrogen and micronized progesterone therapy upon lipoprotein metabolism in postmenopausal women. J Lipid Res 41:368-75
Vicini, P; Zachwieja, J J; Yarasheski, K E et al. (1999) Glucose production during an IVGTT by deconvolution: validation with the tracer-to-tracee clamp technique. Am J Physiol 276:E285-94
Parhofer, K G; Barrett, P H; Schwandt, P (1999) Low density lipoprotein apolipoprotein B metabolism: comparison of two methods to establish kinetic parameters. Atherosclerosis 144:159-66
Vicini, P; Caumo, A; Cobelli, C (1999) Glucose effectiveness and insulin sensitivity from the minimal models: consequences of undermodeling assessed by Monte Carlo simulation. IEEE Trans Biomed Eng 46:130-7
Burnett, J R; Wilcox, L J; Telford, D E et al. (1999) The magnitude of decrease in hepatic very low density lipoprotein apolipoprotein B secretion is determined by the extent of 3-hydroxy-3-methylglutaryl coenzyme A reductase inhibition in miniature pigs. Endocrinology 140:5293-302
Vicini, P; Cobelli, C (1999) A priori identifiability of distributed models of blood-tissue exchange. Ann Biomed Eng 27:200-7
Cobelli, C; Caumo, A; Omenetto, M (1999) Minimal model SG overestimation and SI underestimation: improved accuracy by a Bayesian two-compartment model. Am J Physiol 277:E481-8
Bertoldo, A; Vicini, P; Sambuceti, G et al. (1998) Evaluation of compartmental and spectral analysis models of [18F]FDG kinetics for heart and brain studies with PET. IEEE Trans Biomed Eng 45:1429-48
Barrett, P H; Bell, B M; Cobelli, C et al. (1998) SAAM II: Simulation, Analysis, and Modeling Software for tracer and pharmacokinetic studies. Metabolism 47:484-92
Cobelli, C; Caumo, A (1998) Using what is accessible to measure that which is not: necessity of model of system. Metabolism 47:1009-35

Showing the most recent 10 out of 69 publications