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The Influence of Body Weight and Cell Size on Lipogenesis and Lipolysis of Isolated Rat Fat Cells *
Author(s) -
Hansen F. Mólgaard,
Nielsen J. Høiriis,
Gliemann J.
Publication year - 1974
Publication title -
european journal of clinical investigation
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.164
H-Index - 107
eISSN - 1365-2362
pISSN - 0014-2972
DOI - 10.1111/j.1365-2362.1974.tb00414.x
Subject(s) - lipogenesis , lipolysis , medicine , osmium tetroxide , endocrinology , insulin , adipose tissue , chemistry , glucagon , cell size , cell , biology , biochemistry , electron microscope , physics , microbiology and biotechnology , optics
. A method for fractionating isolated fat cells is described. After fixation with osmium tetroxide, the cells are passed through a series of polyamide filters of decreasing mesh width and the number of cells on each filter is counted. – Isolated fat cells from ad libitum fed rats weighing 85–580 g were incubated with [U‐ 14 C]‐glucose (0.55 mM), fixed with osmium tetroxide and fractionated according to size. When the cells were obtained from one animal the conversion of glucose to neutral lipids per cell increased with increasing cell size just as well in the absence of insulin as in the presence of insulin (10 mU/ml). The following results were obtained from comparisons between animals of different weight: in the absence of insulin, the lipogenesis for cells of the same size remained constant irrespective of the rat weight, whereas in the presence of insulin the lipogenesis for cells of the same size decreased markedly when the rat weight exceeded about 300 g. It is concluded that factors other than the cell size per st (e.g. age, degree of obesity) determine the responsiveness to insulin. – The hormone‐stimulated lipolysis was studied on unfractionated cell samples from ad libitum fed rats of different weights and the following was found: the glycerol release per 10 5 cells induced by ACTH and norepinephrine in maximally stimulating concentrations increased with increasing mean cell size or rat weight. In contrast, the glucagon‐induced lipolysis of cells from rats weighing 300–400 g was smaller than that of cells from rats weighing 100–120 g.