Heparin-induced Lipemia Clearing Factor in Rats: Role of the Pancreas in its Production

Meng, H. C.; Goldfarb, June L

doi:10.2337/diab.8.3.211

Cited by 16 publications

(3 citation statements)

References 3 publications

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“…However, Kreisberg 12 has -shown that the hydrolysis, uptake and oxidation of chylomicron tripalmitin-C-14 by isolated perfused hearts of alloxan diabetic rats were decreased as compared to those of normal hearts; these results suggest a decrease in clearing factor lipase activity. Meng and Goldfarb 16 have also shown that the clearing activity of postheparin plasma of alloxan diabetic and depancreatized rats was markedly reduced. A similar difference in lipase activity of hearts of fasted rats has also been reported: Several investigators, 2 ' 3 ' 7 -10 have found that the lipase release from and activity of the myocardial tissues in the fasted state are increased.…”

Section: Discussionmentioning

confidence: 94%

Release of Clearing Factor Lipase (Lipoprotein Lipase) in Vivo and from Isolated Perfused Hearts of Alloxan Diabetic Rats

Aktin¹,

Meng²

1972

Diabetes

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The release*of clearing factor lipase (CFL) into the blood stream after heparin injection and from hearts during perfusion with a heparin-containing fluid was studied using normal and alloxan diabetic rats. In addition, the effect of alloxan diabetes on heart tissue lipase activity and the "repletion" of this enzyme in previous "depleted" animals by pre-injection of heparin were also investigated. The results show that the plasma CFL activity after an injection of a standard dose of heparin and that of the medium incubated with heart slices or homogenates in the presence of heparin was significantly decreased in alloxan diabetic rats. CFL release from isolated perfused hearts of alloxan diabetic rats was comparable to that from hearts of normal animals during the snort perfusion period of five to ten minutes. However, the enzyme release from hearts of alloxan diabetic rats was considerably decreased during prolonged perfusion. Addition of insulin and glucose to the fluid perfusing hearts of diabetic animals did not correct the defect. Insulin treatment restored the CFL activity in plasma, heart slices, homogenates, and perfusates to normal levels. The CFL release into the blood stream or from perfused hearts of rats previously treated with heparin was decreased when rats were given a second injection of this agent or when rats were killed and hearts were perfused less than two hours after the first heparin administration. This decrease was more marked in diabetic than in normal rats. The "repletion" of CFL in hearts of normal rats was completed in three hours with an overshoot four hours after heparin injection. The CFL release from perfused hearts of diabetic rats remained at a low, depleted level even eight hours after heparin administration. The heart tissue lipase activity in rats with heparin pretreatment was also decreased; this decrease was more marked in diabetic than in normal animals. The "repletion" of tissue lipase was also much slower in diabetic rats. Omission of heparin in the incubation medium of heart slices and the perfusion fluid markedly decreased the lipase release especially that from the perfused heart; the decrease was very slight in the incubation medium of heart homogenates. Tissue and perfusate lipase were inhibited by sodium chloride and protamine.

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Section: Discussionmentioning

confidence: 94%

Release of Clearing Factor Lipase (Lipoprotein Lipase) in Vivo and from Isolated Perfused Hearts of Alloxan Diabetic Rats

Aktin¹,

Meng²

1972

Diabetes

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“…This decrease in adipose tissue clearing-factor lipase activity is correlated with the plasma insulin concentration and inversely correlated with the plasma fatty acids. The effect of insulin on clearing-factor lipase activity in adipose tissue of rats in vitro and in vivo is well established (Wing et al, 1966;Meng & Goldfarb, 1959;Schnatz & Williams, 1963), whereas Wing & Robinson (1968) observed that clearing-factor lipase activity could be decreased in the absence of an increase in the tissue fatty acid concentration. The increase in pig plasma fatty acids during starvation in the present study is similar to that found by Hertelendy et al (1970), but lower than the changes reported by Cunningham & Friend (1965), who used a less specific assay.…”

Section: Discussionmentioning

confidence: 99%

Clearing-factor lipase in muscle and adipose tissue of pigs

Enser

1973

Biochemical Journal

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1. Clearing-factor lipase was assayed in acetone-ether-dried powders of heart and adipose tissue of pigs. The enzyme activity in heart was higher than that in adipose tissue. The activity in the outer layer of subcutaneous fat was greater than that in the inner subcutaneous fat and the perirenal fat, which had similar activities. 2. Starvation for 48h, but not for 24h, decreased the activity of the heart enzyme. 3. Starvation for 24h caused a rapid decrease in the activity in all three adipose tissues, but even after 72h of starvation the activity was still highest in the outer subcutaneous fat. 4. Plasma fatty acid, glucose and insulin concentrations were determined in fed and starved pigs. Starvation decreased the plasma insulin concentration and increased the non-esterified fatty acid concentration.

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“…The mechanism by which clearing-factor lipase activity is regulated is not known. Wing et al (1966) demonstrated that insulin promoted an increase in the activity of the enzyme in rat epididymal fat-pads, and a requirement for insulin for activity in vivo has been demonstrated in alloxan-diabetic rats (Meng & Goldfarb, 1959;Schnatz & Williams, 1963). Since hyperinsulinaemia is characteristic of obese mice of this strain Stauffacher et al, 1967), this could be one factor contributing to the increased clearing-factor lipase activity.…”

Section: Discussionmentioning

confidence: 99%

Clearing-factor lipase in obese–hyperglycaemic mice (ob/ob)

Enser

1972

Biochemical Journal

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1. Clearing-factor lipase was assayed in acetone-ether-dried powders of heart and epididymal fat-pads of lean and genetically obese mice (ob/ob). In both tissues the enzyme activity in the adult was higher in the obese mice. 2. In heart the enzyme activity was unchanged from 8 to 48 weeks of age in lean mice, but in obese mice it increased between 8 and 12 weeks of age and remained elevated. 3. Starvation produced changes in the heart clearing-factor lipase activity in obese, but not lean, mice. 4. The clearing-factor lipase activity of epididymal fat-pads decreased rapidly during 24h starvation in both lean and obese mice, but the activity in the obese mice remained higher than that in lean mice. 5. Plasma triglyceride and cholesterol concentrations were determined in both lean and obese mice. Triglyceride concentrations were not greatly different, but the obese mice were hypercholesterolaemic. Plasma cholesterol concentrations were not correlated with changes in clearing-factor lipase activity.

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Heparin-induced Lipemia Clearing Factor in Rats: Role of the Pancreas in its Production

Cited by 16 publications

References 3 publications

Release of Clearing Factor Lipase (Lipoprotein Lipase) in Vivo and from Isolated Perfused Hearts of Alloxan Diabetic Rats

Release of Clearing Factor Lipase (Lipoprotein Lipase) in Vivo and from Isolated Perfused Hearts of Alloxan Diabetic Rats

Clearing-factor lipase in muscle and adipose tissue of pigs

Clearing-factor lipase in obese–hyperglycaemic mice (ob/ob)

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