title: Comparative in vivo and in vitro study of the influence of experimental diabetes on rat liver linoleic acid delta 6- and delta 5-desaturation.
abstract: Rats with experimental diabetes were administered in vivo a tracer dose of either [1-14C]-linoleic, [1-14C]-gamma-linolenic or [2-14C]-dihomo-gamma-linolenic acid and sacrificed 48 h later. With all three radioactive precursors, the radioactivity incorporated into arachidonic acid was lower in experimental diabetes, compared to nondiabetic rats similarly treated, while the weights of hepatic arachidonic acid were not significantly affected by the diabetic state. Streptozotocin-treated rats were administered moderate or excessive quantities of protamine-zinc-insulin. Streptozotocin diabetes inhibits rat liver homogenate [2-14C]-dihomo-gamma-linolenic acid delta 5-desaturation; only moderate injections of protamine-zinc-insulin restore the in vitro delta 5-desaturation. These results suggest that experimental diabetes, a reported inhibitor of delta 6-desaturation, also causes partial inhibition of delta 5-desaturation in rat liver; this suggests that dihomo-gamma-linolenic acid desaturation, a secondary regulatory step in linoleic acid metabolism, may be restored through an optimum insulin therapy.
mesh_terms: D015126:8,11,14-Eicosatrienoic Acid / Q000378:metabolism; D000818:Animals; D001095:Arachidonic Acids / Q000096:biosynthesis; D000090943:Delta-5 Fatty Acid Desaturase; D003921:Diabetes Mellitus, Experimental / Q000201:enzymology*; D004305:Dose-Response Relationship, Drug; D044943:Fatty Acid Desaturases / Q000378:metabolism*; D005227:Fatty Acids / Q000378:metabolism; D007328:Insulin / Q000494:pharmacology; D019787:Linoleic Acid; D008041:Linoleic Acids / Q000378:metabolism; D008042:Linolenic Acids / Q000378:metabolism; D050602:Linoleoyl-CoA Desaturase; D008099:Liver / Q000201:enzymology* / Q000378:metabolism; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D017965:gamma-Linolenic Acid
chemical_list: D001095:Arachidonic Acids; D000090943:Delta-5 Fatty Acid Desaturase; D005227:Fatty Acids; D007328:Insulin; D008041:Linoleic Acids; D008042:Linolenic Acids; D017965:gamma-Linolenic Acid; D019787:Linoleic Acid; D044943:Fatty Acid Desaturases; D050602:Linoleoyl-CoA Desaturase; D015126:8,11,14-Eicosatrienoic Acid