Gamma Linoleic Acid and Trans Linoleic Acid Effects on Atherogenic Dieted Rabbit Tissue Sensitivity to Insulin

Abstract

The effects of adding 5% Primrose oil‐(PO) [ containing 9% Gamma Linolenic Acid (GLA)] and/or 5% Soy Oil (SO) [containing 35% Trans Linoleic acid (TLA)] ‐to the Atherogenic Diet (AD) fed to rabbits for a 30 day interval, were studied regarding their ability to alter their tissue sensitivity to insulin. New Zealand strain male rabbits were divided into diet groups with four animals/group. Group I‐(AD Control ) rabbits were maintained on AD containing 92% Purina Rabbit Chow, 6% Corn Oil and 2% Cholesterol. Group II (AD+SO) animals were fed AD + 5% SO, Group III (AD+PO) animals received AD+ 5%.PO, and Group IV (AD+SO+PO), rabbits were fed AD + 2.5% PO and 2.5% SO. Blood platelet samples were isolated from the blood plasma samples drawn from each group. These were incubated in media with exogenous insulin and glucose then washed, homogenized and assayed for their glucose content. The mean glucose values determined in the platelet homogenates were: I. (AD Control ) : 0.41mg/dl, II. (AD+SO ): 0.51mg/dl, III. (AD+ PO): 1.09 mg/dl and IV. (AD + {2.5%PO + 2.5% SO): 0.96 mg/dl. The mean cholesterol levels found in the blood plasma samples of these groups were: I. (AD Controls): 72.6mg/dl. II. (AD+ SO): 73.5 mg ‘dl, III. (AD+PO): 52mg/dl, and in IV. (AD+ (2.5%SO and 2.5%PO), the level rose to 59 mg/dl. Blood platelet mean cholesterol levels were : I. (AD Control) :75.6mg/dl, II. (AD +SO): 56.3mg/dl, III. (AD+PO) values fell to 33.3 mg/dl, and IV. (AD+2.5%PO+2.5%SO): 33.9mg/dl. Rabbits fed AD with PO/GLA supplement, were found to have reduced plaque development in their aortae at autopsy compared to the those lacking GLA supplement in the diet. GLA supplementation to an atherogenic diet appears in these findings to work against the development of hypercholesterolemia and decresased sensitivity to insulin that develops in rabbits with prolonged feeding of an atherogenic diet containing 2% cholesterol as well as atherogenic plaque build up in the aorta..Support or Funding InformationAmerican Heart Association‐ Louisiana