USE OF PROTON SPECTROSCOPY FOR DETECTION OF HOMOZYGOUS FATTY ZDF-DRT RATS BEFORE WEANING

OBJECTIVE: To investigate the use of proton spectroscopy to measure ab dominal fat content in pre-obese offspring of obese and lean Zucker di abetic fatty (ZDF-drt) rats. DESIGN: Large and small litters (size 4-1 5, 127 pups total) were serially measured during the suckling period t o assess their abdominal fat index (AFI) and subsequently identified a s to their genotype (fa/fa obese or Fa/? lean), MEASUREMENTS: Body wei ght, abdominal fat index (derived from percent fat by proton spectrosc opy x body weight), When the abdominal fat index was plotted vs body w eight, the data fell along two regression lines that distinguished pre -obese from lean pups, Percent fat by proton spectroscopy was validate d against chemical measurement, RESULTS: Genotypes of pre-obese and le an pups were distinguishable from 13 days of age onwards, The procedur e allowed prediction of genotype with 98% accuracy at 12-15 days and w as 100% reliable at 16 days and beyond, The rate of fat accretion in t he pups correlated directly with genotype, litter size and caloric den sity of the mother's food, CONCLUSION: Unlike currently available meth ods, the technique is rapid, simple, non-invasive and has the addition al advantage of providing a measure of fat content sequentially over t ime in the same animal. It should be useful for the study of early met abolic derangements in the development of obesity and non-insulin depe ndent diabetes syndromes.