Increased cellular proliferation in adipose tissue of adult rats fed a high-fat diet.

B J Klyde,J Hirsch

doi:10.1016/s0022-2275(20)40024-0

Abstract

The feeding of a high-fat diet to adult rats was shown to increase the incorporation of [3H]thymidine into DNA of the adipocyte and stromal fractions. After only 2 days on a high-fat diet there was a marked increase in the incorporation of label. When a 2-week period was interposed between [3H]thymidine administration and determination of DNA specific activity, the greatest increase in incorporation of label was found after 1 week on the diet, when incorporation increased 6-fold or more in both adipocytes and stroma and subsequently decreased to stabilize at a level two or three times that of chow-fed rats in the adipocyte fraction. Rats labeled when young and later placed on a high-fat diet showed a decrease in DNA specific activity in both adipocytes and stroma, confirming that cellular proliferation had occurred in both fractions. The specific activities of both stromal and adipocyte DNA were very similar at all time points studied. An attempt to increase the difference in specific activities by waiting many weeks after [3H]thymidine injection before isolating DNA was not successful. This may be because the total amount of DNA in the stromal and adipocyte fractions increases in parallel on the diet. The significance of these findings in terms of the normal turnover of adipose tissue DNA and the responsiveness to diet is discussed.

Highlights

The feeding of a high-fat diet to adult rats was shown to increase the incorporation of [3H]thymidineinto DNA of the adipocyte and stromal fractions
Faust et al (8) found that the diet-induced increase in adipocyte number in adult rats occurred in other fat depots, and they demonstrated that the increased adipocyte number persisted even after animals were returned to an ordinary chow diet
In the present work we show that in adult rats a high-fat diet causes a considerable increase in the DNA specific activity of both the adipocyte and stromal fractions, suggesting that the diet-induced increase in cell number is a consequence of cellular proliferation rather than the filling of existing preadipocytes

Summary

Introduction

The feeding of a high-fat diet to adult rats was shown to increase the incorporation of [3H]thymidineinto DNA of the adipocyte and stromal fractions. An attempt to increase the difference in specific activities by waiting many weeks after [3H]thymidineinjection before isolating DNA was not successful This may be because the total amount of DNA in the stromal and adipocyte fractions increases in parallel on the diet. Increased cellular proliferation in adipose tissue of adult rats fed a high-fat diet.J.Lipid Res. 1979. In the present work we show that in adult rats a high-fat diet causes a considerable increase in the DNA specific activity of both the adipocyte and stromal fractions, suggesting that the diet-induced increase in cell number is a consequence of cellular proliferation rather than the filling of existing preadipocytes

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Results

Conclusion