Proceedings of The Physiological Society
Puerto de la Cruz, Tenerife (2003) J Physiol 548P, P180
A comparative study of lipid compositions from isolated enterocytes and subjacent tissues from the intestinal tract of gilthead seabream (Sparus aurata)
C. Rodríguez, R. Dópido, T. Gómez, E. Almansa and M. Díaz
Department of Animal Biology, University of La Laguna, Tenerife, Spain
In the present study, the lipid classes and the fatty acid compositions of the polar lipids from both isolated enterocytes and the underlying intestinal tissue (mainly smooth muscle) were analysed in gilthead seabream (Sparus aurata) following a procedure previously described (Dópido et al. 2001). The fish were killed in accordance with the requirements of the European Convention for the Care and Use of Laboratory Animals. Considering that the physiology of the digestive tract also varies along its proximal-distal axis, and in order to establish a possible relationship between the intestinal cellular functions and their lipid compositions, these analyses were performed on cells and tissues isolated from the three intestinal regions, i.e. pyloric caeca (PC), anterior intestine (AI) and posterior intestine (PI).
The smooth muscle from the three intestinal regions contained higher amounts of cholesterol and lower amounts of polar lipids (particularly phosphatidylcholine and phosphatidylinositol), than the corresponding enterocytes. Additionally, polar lipids from enterocytes were always richer in 22:6n-3 (DHA) and poorer in18:1n-9 (oleic acid) than the subjacent tissue, suggesting the relevant role for polar lipids and DHA in the enterocyte physiology.
When comparing the enterocyte lipid composition between the three intestinal sections, important differences were found adding more evidence to the well known proximal-distal differential physiology of the digestive tract. For instance, there was an increasing presence of free fatty acids in the enterocytes from the caeca to posterior intestine. However, phosphatidic acid as well as monoacylglycerides, which are both products of lipid digestion, followed the opposite trend. This seems to indicate that enterocytes from both AI and PC are important locations for lipid digestion and that enterocytes from AI and PI are involved in the absorption of these fatty acids.
In summary, a detailed analysis of lipids from isolated enterocytes and the subjacent intestinal tissues from the different intestinal segments reveals a high heterogeneity in both transverse and proximal-distal axis in terms of composition but also are indicative of a distribution of functions that clearly differ from the mammalian paradigm.
This work was supported by grant PI2001/059 from Gobierno Autónomo de Canarias.
Where applicable, experiments conform with Society ethical requirements