Journal of Postgraduate Medicine
 Open access journal indexed with Index Medicus & EMBASE  
     Home | Subscribe | Feedback  

Year : 1978  |  Volume : 24  |  Issue : 1  |  Page : 24-31  

Comparison of the effects of feeding Indian fish liver oils supplemented with or without cholesterol and bile salts on certain enzymes in liver, heart and serum of rats

KG Tanksale, NG Magar 
 Department of Biochemistry and Nutrition, Seth G. S. Medical College, Parel, Bombay-400 012., India

Correspondence Address:
K G Tanksale
Department of Biochemistry and Nutrition, Seth G. S. Medical College, Parel, Bombay-400 012.


The enzymes viz. glucose-6-P-dehydrogenase (EC, cholesterol esterase (EC, aspartate amino transferase (EC and alanine amino transferase ( are intimately related to lipid metabolism. Hence their activities are bound to be affected by the type of dietary fat and substances like bile salts and cholesterol which also influence the lipid metabolism. This relationship between dietary lipid constituent and enzymes was studied in albino rats maintained on diets containing three Indian Shark Liver Oils viz. Waghbeer, Khada mushi and Pisori supple­mented with or without cholesterol and bile salts, Enzyme activities were studied in liver, heart and serum. It was noted that higher unsaturation of dietary fat increased the activity of glucose-6-P­dehydrogenase enzyme while activities of transaminases and chole­sterol esterase were lowered. Addition of cholesterol and bile salts to these diets decreased the activity of glucose-6-P-dehydrogenase and hydrolytic activity of cholesterol esterase. There was increase in the activities of transaminases and esterifying activity of choles­terol esterase due to supplementation with cholesterol and bile salts.

How to cite this article:
Tanksale K G, Magar N G. Comparison of the effects of feeding Indian fish liver oils supplemented with or without cholesterol and bile salts on certain enzymes in liver, heart and serum of rats.J Postgrad Med 1978;24:24-31

How to cite this URL:
Tanksale K G, Magar N G. Comparison of the effects of feeding Indian fish liver oils supplemented with or without cholesterol and bile salts on certain enzymes in liver, heart and serum of rats. J Postgrad Med [serial online] 1978 [cited 2023 Apr 1 ];24:24-31
Available from:

Full Text


It has been shown in rats that dietary proteins, fats and carbohydrates markedly affect various enzyme systems, [5],[6],[11],[12] particularly those related to lipid meta­bolism. Perez et al [19] have also shown that glucose-6-phosphate dehydrogenase (EC activity increases with high levels of proteins and decreases with high fat diet. [34] Effect of fat free diet and Essen­tial Fatty Acid (EFA) deficient diet on cholesterol esterase (EC activity has been studied. [1],[22] Influence of chole­sterol and bile salt feeding on certain enzymes related to lipid metabolism has been studied by several authors. [28],[29],[31] Century and Horwit [4] have studied the influence of Poly Unsaturated Fatty Acids (PUFA) on certain enzymes. These re­sults, however, are inconclusive and hence the present studies were undertaken. In this study we used three Indian Fish Liver Oils viz. Waghbeer (Galeocerdo tigrinus), Khada mushi (Carcharinus melanopterus) and Pisori (Carcharinus limbatus) which have been reported [3] to have low PUFA activity. These fish liver oils are the major source for commercial extraction of vitamin A [27] and certain aspects of their nutritive value have beer reported. [24],[25]

 Material and Methods

Analysis of Shark Liver oils: The three fish liver oils were obtained from Fisheries Technological Laboratories Bombay. Chemical constants like acid value, saponification value, iodine value peroxide value and unsaponifiable matter were determined by standard methods of A.O.C.S. [14]

Animal Experiment: Weanling mile .and female albino , rats were used for the present investigation. These rats were divided into five groups each having six males (sub-group A) and six females (sub-group B). All the animals were housed in individual cages throughout the experimental period. They were fed with diets containing Hegsted's modified salt mixture [10] and Schultz vitamin mix­ture [21] as shown in [Table 1]. Fresh diets and water were given on ad-libitum basis for a period of eight weeks. Daily food consumption was noted to see whe­ther it was normal and consistent.

After the experimental period rats were fasted overnight and were sacrificed and blood was collected by cardiac puncture. Liver and heart tissues were excised quickly, blotted and weighed quantities were taken for analyses. Tissue homoge­nates were prepared in 0.25 M ice cold sucrose solution. Proteins were estimated by the method of Gornall [9] , Glucose-6 phosphate dehydrogenase (EC by the method of Kornberg and Horec­ker, [13] cholesterol esterase (EC by the method of Murthy and Ganguly [15] and aspartate amino transferase (AS-At) (EC and alanine amino trans­ferase (Al-At) (EC by the me­thod of Reitm..aand Frankel. [20]


[Table 2] shows chemical constants of the three Shark Liver oils. Khada mushi has the highest iodine value and that of Waghbeer oil is the lowest.

[Table 3] and [Table 4] show the data of enzyme activities from liver, heart and serum of rats in various groups. There is no stati­stical dfference in the results on the basis of sex difference of the animals in any of the groups studied.

Activity of glucose-6-P-dehydrogenase was found to be significantly higher in liver, heart and serum of rats fed diets containing Khada mushi oil as compared to that of rats fed diets containing Wagh­beer oil. When cholesterol was added to diets containing Waghbeer oil there was significant suppression of activity of this enzyme both in males and females. Fur­ther addition of bile salts to the diet re­sulted in further and significant decrease in the activity of glucose-6-P-dehydroge­nase.

Cholesterol esterase enzyme was studi­ed for its hydrolytic as well as esterifying activity. The activities were significantly higher in serum of rats fed diets contain­ing Waghbeer oil. On addition of chole­sterol to the diet containing Waghbeer oil, the hydrolytic activity was significantly lowered while esterfying activity was in­creased significantly. Additional supple­mentation with bile salts caused further decrease in the hydrolylic activity and in­crease in the esterifying activity. These changes were statistically significant.

Activities of both aspartate and alanine amino transferases were significantly higher in the liver, heart and serum of rats in Group 1 as compared to Group 2. When the diet containing Waghbeer oil was supplemented with cholesterol and bile salts, there was a significant rise in the activities of these enzymes in the tissues mentioned above. In case of rats fed Pisori oil, no significant differences were observed in the activity of any of the enzymes studied in various tissues and sera as compared to those observed in rats fed Waghbeer oil.


The enzyme activities did not show any difference on the basis of sex difference of the animals. Differences, however, were observed due to inclusion of three shark liver oils characterised by different iodine values, absence of linoleic acid and low PUFA content [24] in the diet.

The relation between the activity of glucose-6-P-dehydrogenase and unsatura­tion or PUFA content of dietary lipid was shown by Tepperman and Tepperman [26] as a feed back mechanism. The activity of this enzyme was further shown to be re­lated to lipogenesis in the liver. [2],[12] The activity became less with decreased lipo­genesis. Waghbeer oil feeding resulted into decreased activity of glucose-6-P­dehydrogenase in the liver, heart and serum where hepatic activity was related to lipogenesis. There was a significant difference between the activities of glu­cose-6-P-dehydrogenase shown by rats fed Waghbeer oil and that shown by rats fed Khada mushi oil. This was possibly due to difference in the iodine values and fatty acid composition of these two fish liver oils. [24]

Effect of feeding cholesterol showed further significant decrease in the activity of glucose-6-P-dehydrogenase. According to Tsai and Dyer [28] feeding cholesterol resulted into its accumulation which was a probable cause of the decreased activity of glucose-6-P-dehydrogenase. These authors [29] have also shown that feeding cholesterol and bile acids lowered the acti­vity of glucose-6-P-dehydrogenase still further due to enhanced accumulation of cholesterol. Observations in the present investigation also confirm the above findings.

Activities of amino transferases are connected with pyruvate and oxalo-ace­tate metabolism which in turn is related to lipid metabolism through gluconeo­genesis or through lactate/pyruvate ratio. According to Yeh et al [33] dietary lipid alters lactate/pyruvate ratio and ultimate­ly NADH/NAD ratio which serves as an index of availability of reducing equiva­lents needed for lipogenesis. In the pre­sent study feeding fish liver oil with higher unsaturation viz. Khada mushi oil, caused significant decrease in the activi­ties of these enzymes as compared to the data obtained in rats fed Waghbeer oil. Addition of cholesterol and bile salts to the diet containing Waghbeer oil increas­ed the activity of these enzymes and in­creased lipogenesis may be the probable cause.

Conversion of cholesterol esters into free cholesterol and re-esterification is due to the activity of cholesterol esterase and related to the transport of choleste­rol. [17] Dietary fat influences the esterify­ing and hydrolytic activity of cholesterol esterase. [16] In the present investigation three fish liver oils of different iodine values viz. 100 (Waghbeer oil), 143 (Khada mushi oil) and 114 (Pisori oil) were used. As the unsaturation of dietary fat increased there was decrease in the esterifying activity with corresponding decrease in hydrolytic activity of chole­sterol esterase and these findings are in agreement with those of Goodman, [8] Nestle and Monger, [18] and Glomset [7] , It was fur­ther shown by Takeuchi and Yamamura [23] that addition of cholesterol to the diet increased the esterifying activity. In the present study with addition of cholesterol to the diet containing Waghbeer oil there was a significant increase in the esterify­ing activity and decrease in hydrolytic activity and further supplementation with bile salts increased the esterifying acti­vity still further and decreased the hydrolytic activity also. According to Trze ciak and Boyed [30] cAMP levels in plasm, are related to cholesterol esterase. It is therefore, probable that unsaturation: dietary fat, cholesterol and bile salt influence cholesterol esterase through this mechanism involving cAMP.


Authors are thankful to the Dean, Seth G. S. Medical College, Bombay-400 012 for the permission to publish this article and to the Assistant Director, Fisheries Tech­nological Laboratories, Bombay for sup­plying the fish liver oils.


1Aftergood, L. and Alfin-Slater, R. B.: Sex difference in plasma cholesterol esterifying activity in rats, J. Lipid Res. 8: 126-130, 1967.
2Alle, G. A., O'Hea, E. K., Leveille, G. A. and Baker, D. H.: Influence of die­tary protein and fat on lipogenesis and enzymatic activity in pig adipose tissue. J. Nutr., 101: 868-878, 1971.
3Bhathena, S. J. and Magar, N. G.: Nu­tritive value of Indian Fish liver oils and their effect of the fatty acid composition of liver, serum and adipose tissue of rat, Ind. J. Med. Res., 60: 1043-1053, 1972.
4Century, B. and Horwit, M. K.: Effect of dietary lipid upon some enzymes of significance in Biogenic amine metabolism in rat., J. Nutr., 95: 509-516, 1968.
5Chang, M. L. W., Lee, J. A. and Tror D. L.: Effect of dietary egg and carbo­hydrates on hexose monophosphate shunt dehydrogenases and lipids of liver in rats. J. Nutr., 100: 1317-1322, 1970.
6Gidez, L. I.: Effect of dietary fat on pan­creatic lipase in the rat. J. Lipid Res., 14: 169-177, 1973.
7Glomset, J.: Plasma lecithin: cholesterol acyl transferase reaction. J. Lipid Res., 9: 155-167, 1968.
8Goodman, De, W. S.: Cholesterol ester metabolism. Physiol. Rev., 45: 747-839, 1965.
9Gornall, A. G., Bardwill, C. J. and David, M. M.: Determination of serum proteins by means of biuret reaction. J. Biol. Chem., 177: 571-766, 1949.
10Hegsted, D. M., Mill, R. C., Elvehjem, C. A. and Hart, E. B.: Choline in the nutrition of chicks. J., Biol. Chem., 133: 459-466, 1941.
11Johnson, B. C., Moser, K. and Sasson, H. F.: Dietary induction of liver glu­cose-6-phosphate dehydrogenase enzyme in the rat. Proc. Soc. Exptl. Biol. and Med., 121: 30-31, 1966.
12Kim, Y. K.: Changes in lipid composi­tion and some enzyme activities in rat liver as affected by diets, Korean J. Nutr., 6: 18-23, 1973.
13Kornberg, A. and Horecker, B. L.: In "Methods in Enzymology", Editors-Col­wic, S. P. and Kaplan, N. 0., Vol. I, Academic Press, New York, 1955, p. 323-­324.
14Mehlenbacker, V. C.: Official and Ten­tative Methods of American Oil Chemists' Society. 1946, Methods Ca-5-40, Cd-3-25, Cd-1-25, Cd-8-53, Ca-11-42.
15Murthy, S. K. and Ganguly, J.: Studies in cholesterol esterase of small intestine and pancreas of rats. Biochem. J., 83: 460-469, 1962.
16Nestle, P. J.: Turnover of plasma esteri­fled cholesterol; Influence of dietary fat and carbohydrates and relation to plasma lipids and body weight. Clinical Science, 38: 593-600, 1970.
17Nestle, P. J. and Couzens, E. A.: Turn­over of individual cholesterol esters in human liver and plasma. J. Clin. Invest., 45: 1234-1240, 1966.
18Nestle, P. J. and Monger, E. A.: Turn­over of plasma esterified cholesterol in normocholesterolemic and hypercholeste­rolemic subjects and its relation to body build., J. Clin. Invest., 46: 967-974, 1967.
19Perez, N., Clark, Jurri, L., Rabajlli, E. and Niemyer, H.: Regulation of rat liver enzymes by natural components of the diet. J. Biol. Chem. 239: 2420-2446, 1964.
20Reitman, S. and Frankel, S.: A colori­metric method for the determination of serum glutamic oxalo acetic and glutamic pyruvic transaminases. Amer. J. Clin. Pathol., 28: 56-63, 1957.
2121. Schultz, M. 0.: Nutritional value of plant materials I. Growth of rats on puri­fied rations containing soyabean protein. J. Nutr., 41: 103-113, 1950.
22Sugano, M. and Portman, O. W.: Essential fatty acid deficiency and cholesterol esterification activity of plasma in vitro and in vivo., Arch. Biochem. Biophys., 109: 302-315, 1965.
23Takeuchi, N. and Yamamura, Y.: Cho­lesterol esterification and cholesterol ester hydrolysis by liver homogenates in the rats with accelerated cholesterol metabol is.Atherosclerosis, 17: 211-216, 1973.
24Tanksale, K. G. and Magar, N. G.: Nu­tritive value of Indian Shark Liver Oils (I-Effect of feeding Fish liver oils on growth, organ weights and tissue lipids in rats. Ind. J. Exptl. Biol., 15 (1977) (In press).
25Tanksale, K. G. and Magar, N. G.: Nu­tritive value cf Indian shark liver oils (II-Effect of feeding Fish liver oils on Nitrogen Balance in Rats. Ind. J. Exptl. Biol., 15 (1577) (In press).
26Tepperman, H. M. and Tepperman, J.: Effect of saturated fat diets on liver NAD­linked enzymes. Amer. J. Physiol., 209: 773-780, 1965.
27The Wealth of India. Industrial Products, Part IV, Council of Scientific and Indus­trial Research, New Delhi, 1957, p. 60.
28Tsai, A. C. and Dyer, I. A.: Liver cho­lesterol concentration in relation to he­patic cholesterogenesis and activity of certain liver enzymes in rats. J. Nutr., 103: 1119-1125, 1973.
29Tsai, A. C. and Dyer, I. A.: E:ect of dietary cholesterol on the activity of car­bohydrate metabolism enzymes in the liver of rats. J. Nutr., 102: 1039-1046, 1972.
30Trzeciak, W. H. and Boyd, G. S.: Acti­vation of Cholesterol esterase in Bovine cortex, Europ. J. Biochem., 46: 201-207,1974.
31Vahony, G. V., Weersing, S. and Tread­well, C. R.: Functions of specific bile acids in cholesterol esterase activity in vitro. Biochem. Biophys. Acata., 93: 607-616, 1965.
32Wergedal, J. E. and Harper, A. E.: Me­tabolic adaptation in higher animals. J. Biol. Chem., 239: 1156-1163, 1964.
33Yeh Yu Yau and Levelle, G. A.: Studies on the relationship between lipogenesis and the levels of Co-enzyme A derivatives. lactate and. pyruvate in chick liver. J. Nutr., 101: 911-917, 1971.
34Yugari, Y. and Matasuda, T.: Glucose-6­phosphate dehydrogenese from rat liver. J. Biochem.. 61: 541-549, 1967.

Saturday, April 1, 2023
 Site Map | Home | Contact Us | Feedback | Copyright  and disclaimer