Eb. Thorling et Hs. Hansen, AGE-RELATED-CHANGES IN THE PERCENTAGE OF OLEATE IN ADIPOSE-TISSUE OF MALE AND FEMALE FISCHER RATS, Biochimica et biophysica acta, L. Lipids and lipid metabolism, 1258(2), 1995, pp. 195-198
Fischer 344 rats showed sex difference in the percentage of oleate in
lipids of the omental adipose tissue (Thorling, E.B. and Overvad, K. (
1994) Nutr. Res. 14, 569-576). The development of this difference was
studied with respect to time in rats maintained on laboratory chow, fr
om the age of 3 weeks to 20 weeks. From the age of 3 weeks to 5 weeks
the percentage of oleate increased slightly in both sexes. From the ag
e of 5 weeks to 13 weeks the percentage (mean +/- S.D., n = 5) increas
ed further in the female rats from 24.8 +/- 0.6% to 27.6 +/- 0.6%, whe
reas in the male rats it dropped from 22.9 +/- 0.4% to 20.2 +/- 0.6% a
t the same time points, respectively. In adult rats, age 20 weeks, the
percentage of oleate was 28.6 +/- 0.3% and 19.6 +/- 0.5% for females
and males, respectively. Castrated males partly maintained their juven
ile level, being 21.1 +/- 1.1% fourteen weeks after castration at the
age of 6 weeks. Oestrogen injections twice a week to the castrated rat
s increased their oleate percentage within the same period to 23.4 +/-
0.3%, partly reflecting the increase observed in the female rats. Ste
aric acid showed similar but less pronounced changes. The ratio oleic
acid/stearic acid was constantly higher in the female than in the male
rats, and this difference increased with age. The results of the pres
ent study suggest that these changes in percentage of oleate in adipos
e tissue lipids may partly have been caused by an effect of sex steroi
ds an the delta-9-desaturase