A Reliable Photomicrographic Method for Determining Fat Cell Size and Number: Application to dietary obesity

Abstract

Rat and human isolated adipocyte sizes were determined by the measurement of their diameter on photomicrographs and by electronic counting of Os-fixed cells. The average cell size was 0.348 and 0.353 .mu.g of lipid/cell, respectively. The agreement between the 2 methods was excellent over a wide range of cell sizes (0.15-0.09 .mu.g of lipid/cell). The photomicrographic method was applied to a morphological study of epididymal adipose tissue in Wistar rats fed a high fat diet for either 1 or 10 mo. The enlargement of the adipose depot induced by 1 mo. of the high fat diet was achieved by an increase of fat cell size only. Ten months of high-fat feeding induced either a moderate obesity with only hypertrophy of the adipocytes or a severe obesity with apparent hypertrophic-hyperplastic changes.