The nature of dietary lipids and their levels can modify the structure and function of salivary glands in several different ways. A likely mode of action would be by virtue of their effect in inducing physiochemical modifications of plasma membrane lipids. Since membrane lipids play an important role in determining the activities of several membrane associated enzymes such as (Na+ + K+)-ATPase and adenyl cyclase in a number of tissues, it is quite likely that the activities of these two enzymes will be affected in salivary glands as well. If so, this may have a profound influence on salivary gland function because of the physiological importance of (Na+ + K+)-ATPase in active transport of ions and that of adenyl cyclase in the secretion of salivary proteins. The objective of the proposed studies is to test the above hypothesis using several nutritional models such as essential fatty acid deficiency, feeding of saturated versus unsaturated fats, cholesterol supplementation and trans fatty acids. Male weanling rats will be fed purified diets containing different levels of linoleic acid, trans fatty acids, cholesterol and two types of fats. At various time intervals, rats will be killed, their submandibular salivary glands (SMSG) will be dissected out and plasma membranes will be prepared. The activities of ouabain sensitive (Na+ +K+)-ATPase (EC and adenyl cyclase (EC will be determined in plasma membrane preparations and in gland homogenates. Fluidity of membranes will be determined by fluorescence spectroscopy using fluorescent probes. Aliquots of SMSG homogenates and plasma membranes will be extracted for lipids and the major phospholipids will be isolated by thin layer chromatography. The fatty acid composition of total lipids and phospholipids will be determined by gas chromatographic methods using packed and open tubular glass capillary columns. All data will be statistically analyzed in order to seek any correlations between the lipid composition, membrane fluidity and the activities of the two enzymes. Samples of submadibular saliva will also be obtained from some rats by duct cannulation. Salvia will be analyzed for total proteins, amylase, Na+ and K+. The effect of lipid nutrition on salivary gland plasma membrane lipid composition, fluidity, enzyme activities and saliva composition will be assessed.

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National Institute of Dental & Craniofacial Research (NIDCR)
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Oral Biology and Medicine Study Section (OBM)
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Louisiana State University Hsc New Orleans
School of Medicine & Dentistry
New Orleans
United States
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Alam, S Q; Shi, Y Y (1997) The effect of essential fatty acid deficiency on the fatty acid composition of different salivary glands and saliva in rats. Arch Oral Biol 42:727-34
Alam, S Q; Abdel-Hakim, S M; Alam, B S et al. (1995) Effect of essential fatty acid deficiency on G-proteins, cAMP-dependent protein kinase activity and mucin secretion in the rat submandibular salivary glands. Cell Signal 7:773-81
Abdel-Hakim, S M; Alam, B S; Alam, S Q (1994) Prostaglandin E2 production in submandibular salivary glands of rats in essential fatty acid deficiency. Prostaglandins Leukot Essent Fatty Acids 50:141-5
Alam, S Q; Mannino, S J; Alam, B S (1993) Reversal of diet-induced changes in adenylate cyclase activity and fatty acid composition of rat submandibular salivary gland lipids. Arch Oral Biol 38:387-91
Alam, S Q; Bergens, B M; Alam, B S (1991) Arachidonic acid, prostaglandin E2 and leukotriene C4 levels in gingiva and submandibular salivary glands of rats fed diets containing n-3 fatty acids. Lipids 26:895-900
Ahmad, S N; Alam, S Q; Alam, B S (1990) Influence of dietary omega-3 fatty acids on transmembrane signalling in rat submandibular salivary gland. Cell Signal 2:29-41
Ahmad, S N; Alam, S Q; Alam, B S (1990) Effect of ageing on adenylate cyclase activity and G-proteins in rat submandibular salivary glands. Arch Oral Biol 35:885-90
Ahmad, S N; Alam, S Q; Alam, B S (1990) Fatty acid incorporation into membranes of dispersed rat submandibular salivary gland cells and their effect on adenylate cyclase activity. Arch Oral Biol 35:879-83
Alam, S Q; Alam, B S (1988) In-vivo incorporation of omega 3 fatty acids into membrane lipids of rat salivary glands and changes in adenylate-cyclase activity. Arch Oral Biol 33:295-9
Ren, Y F; Alam, S Q; Alam, B S et al. (1988) Adenylate cyclase and beta-receptors in salivary glands of rats fed diets containing trans fatty acids. Lipids 23:304-8

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