| Budget Amount *help |
¥6,300,000 (Direct Cost: ¥6,300,000)
Fiscal Year 1986: ¥1,100,000 (Direct Cost: ¥1,100,000)
Fiscal Year 1985: ¥5,200,000 (Direct Cost: ¥5,200,000)
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| Research Abstract |
The Harderian gland is well developed in certain animals, for example, rodents. It occupies aconsiderable part of the orbit and is located around the posterior half of the orbit. This gland has several functions as an extraretinal photoreceptor, regulation of the circadian rhythm and its pheromonal effect, in addition to the excretion of lipids as lubricants. The constituents of the lipids are different from species to species. This gland is an interesting model organ, which has specific functions together with specific membrane constituents. The fatty acid compositions of excretory lipid, 1-alkyl-2,3-diacylglycerol, and the membrane lipids, phosphatidyl choline and phosphatidyl ethanolamine, of the guinea pig Harderian gland were examined. A large amount of methyl-branched fatty acids was detected. The absence of essential fatty acids was also noticed. The fatty acid synthetase of this gland was different from that of liver; the former enzyme produced many odd-numbered and methyl-branched fatty acids in the presence of methylmalonyl-CoA, but the latter enzyme was strongly inhibited by methylmalonyl-CoA. Microsomal glycerol 3-phosphate acyltransferase from the guinea pig Harderian gland was studied. Two distinct types of enzyme were found, one of which is a different enzyme from dihydroxyacetone-P acyltransferase, as reported by other investigators. These results indicated that the Harderian gland is like an "Independent Factory" performing a unique lipid metabolism isolated from surroundings. The natural labeling of fatty acids with methyl-branching is thought to be a useful tool to analyze the lipid metabolism, and it will undoubtedly offer a clue in the near future to elucidate the physiological roles of these lipids in the special functions of Harderian gland.
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