Altered fatty acid pattern of phospholipids and triglycerides in the submandibular gland of omega3-depleted rats.

Alteration of the phospholipid (PL) and triglyceride (TG) fatty acid pattern was recently documented in several organs of rats depleted in long-chain polyunsaturated omega3 fatty acid (omega3 rats). This study extends such a knowledge to the submandibular gland. The total PL and TG content of the salivary gland was not different in control and omega3 rats. The sole omega3 fatty acids found in omega3 rats (C22:5omega3 and C22:6omega3) were present at levels 3-12 times lower than in control rats. The C22:5omega3/C22:6omega3 ratio was increased threefold in omega3 rats. The PL and TG C16:0/C16:1omega7 and C18:0/C18:1omega9 ratios were decreased in omega3 rats. The conversion of C18:2omega6 to C20:4omega6 and C22:4omega6 appeared facilitated in the omega3 rats. Some of these rats were injected intravenously, 60-120 min before killing, with either a medium-chain triglyceride:fish oil emulsion or a control medium-chain triglyceride:olive oil emulsion. The former emulsion increased the PL C22:5omega3 and C22:6omega3 content and prevented the age-related decrease in C16:0/C16:1omega7 and C18:0/C18:1omega9 ratios otherwise also recorded in PL. In conclusion, these findings document an increased activity of Delta9-desaturase, a more efficient conversion of C18:2omega6 to its metabolites, and an impaired generation of C22:6omega3 from C22:5omega3 in omega3 rats.