Keywords: hormone resistanceoxidative stresspara-tyrosine.
Abstract:Former data of our workgroup indicated that the accumulation of oxidized amino acids meta- and ortho-tyrosine due to oxidative stress may play an important role in the impaired insulininduced vasoactive properties of different arterial segments.
There are evidences, that incorporation of these amino acids into cellular proteins leads to certain hormonal resistances, which might be restored by supplementation with the physiologic isoform, para-tyrosine.
Rats in the control group were kept on a regular diet, rats in the cholesterol-fed group received high-fat diet, while the third group of rats received high-fat diet with para-tyrosine insulin resistance diet pdf for 16 weeks. Plasma level of insulin after glucose stimulation was decreased in the cholesterol-fed group, while that in the para-tyrosine supplemented group did not differ significantly from the controls.
Vascular para- meta- and ortho-tyrosine content was measured with HPLC.
Vascular response of the thoracic aorta to insulin and liraglutide was assessed by a DMT multi-myograph. Cholesterol feeding resulted in vascular insulin-and liraglutide resistance, which was restored by para-tyrosine supplementation.
Incorporation of the oxidative stress induced pathological tyrosine isoforms leads to vascular-hormone-resistances. We show that the physiological amino acid para-tyrosine is capable of restoring hypercholesterolemia-induced increased meta-tyrosine content of the vascular wall, thus attenuating functional vascular damage.