Dehydroepiandrosterone modifies rat fatty acid composition of serum and different adipose tissue depots and lowers serum insulin levels

Dehydroepiandrosterone (DHEA) is reported to exert beneficial effects, such as protection from cardiovascular risk and lowering serum insulin levels. Adipose tissue (AT) is a target for DHEA actions, and the hormone can also affect hepatic fatty acid (FA) metabolism. FAs are involved in the development of insulin resistance; thus, there might be a relationship between DHEA, FA, and insulin. However, few data are available regarding DHEA and FA composition, especially concerning AT. Seventeen-month old female Sprague–Dawley rats (n=11; controls: n=10) were treated with DHEA (0.5% w/w in the diet) for 13 weeks, after which serum, periovarian, mesenteric, s.c., and brown AT were analyzed for FA composition. DHEA treatment resulted in significant changes in FA profiles in serum and adipose depots, like reduced 16:1n-7 (s.c. and brown AT; P<0.01), elevated n-9 monounsaturated FA (serum and s.c. AT; P<0.05), diminished n-6 polyunsaturated FA (PUFA; general; P<0.05) and increased n-3 PUFA (brown AT; P<0.01), along with lower n-6/n-3 ratios (s.c. and brown AT; P<0.05, P<0.01 respectively). DHEA modified estimates of desaturase activities, decreasing stearoyl-CoA-desaturase markers in s.c., and brown AT (P<0.05) and increasing those of delta-6-desaturase in serum and AT (P<0.05). In addition, DHEA-treated rats showed lower serum insulin levels (P<0.05). We have demonstrated for the first time that DHEA induces significant modifications in AT fatty acid composition in vivo, mainly concerning unsaturated FAs, and changes occurred in a tissue-dependent manner. We propose that these changes may be related to the capacity of DHEA to lower serum insulin levels.

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Platelet Aggregation in Finnish Men and Its Relation to Fatty Acids in Platelets, Plasma and Adipose Tissue

Thrombosis and Haemostasis ◽

10.1055/s-0038-1660071 ◽

1985 ◽

Vol 54 (03) ◽

pp. 563-569 ◽

Cited By ~ 19

Author(s):

M K Salo ◽

E Vartiainen ◽

P Puska ◽

T Nikkari

Keyword(s):

Fatty Acids ◽

Adipose Tissue ◽

Fatty Acid Composition ◽

Fatty Acid ◽

Platelet Aggregation ◽

Acid Composition ◽

Saturated Fatty Acids ◽

Free Living ◽

Ω3 Fatty Acids ◽

Induced Aggregation

SummaryPlatelet aggregation and its relation to fatty acid composition of platelets, plasma and adipose tissue was determined in 196 randomly selected, free-living, 40-49-year-old men in two regions of Finland (east and southwest) with a nearly twofold difference in the IHD rate.There were no significant east-southwest differences in platelet aggregation induced with ADP, thrombin or epinephrine. ADP-induced platelet secondary aggregation showed significant negative associations with all C20-C22 ω3-fatty acids in platelets (r = -0.26 - -0.40) and with the platelet 20: 5ω3/20: 4ω 6 and ω3/ ω6 ratios, but significant positive correlations with the contents of 18:2 in adipose tissue (r = 0.20) and plasma triglycerides (TG) (r = 0.29). Epinephrine-induced aggregation correlated negatively with 20: 5ω 3 in plasma cholesteryl esters (CE) (r = -0.23) and TG (r = -0.29), and positively with the total percentage of saturated fatty acids in platelets (r = 0.33), but had no significant correlations with any of the ω6-fatty acids. Thrombin-induced aggregation correlated negatively with the ω3/6ω ratio in adipose tissue (r = -0.25) and the 20: 3ω6/20: 4ω 6 ratio in plasma CE (r = -0.27) and free fatty acids (FFA) (r = -0.23), and positively with adipose tissue 18:2 (r = 0.23) and 20:4ω6 (r = 0.22) in plasma phospholipids (PL).The percentages of prostanoid precursors in platelet lipids, i. e. 20: 3ω 6, 20: 4ω 6 and 20 :5ω 3, correlated best with the same fatty acids in plasma CE (r = 0.32 - 0.77) and PL (r = 0.28 - 0.74). Platelet 20: 5ω 3 had highly significant negative correlations with the percentage of 18:2 in adipose tissue and all plasma lipid fractions (r = -0.35 - -0.44).These results suggest that, among a free-living population, relatively small changes in the fatty acid composition of plasma and platelets may be reflected in significant differences in platelet aggregation, and that an increase in linoleate-rich vegetable fat in the diet may not affect platelet function favourably unless it is accompanied by an adequate supply of ω3 fatty acids.

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