The Role of Calcium in Insulin Action - V. Importance of Cyclic Guanosine 3':5' Monophosphate and Calcium Ions in Insulin Stimulation of Lipoprotein Lipase Activity and Protein Synthesis in Adipose Tissue

Meal-fed (3 h) rats had a decreased food intake, body weight and carcass fat compared with rats fed ad libitum. On refeeding a chow meal containing [1-14C]triolein, the production of 14CO2 was lower (45%) and the accumulation of carcass [14C]lipid higher (37%) in the meal-fed rats. There was higher lipoprotein lipase activity and greater accumulation of [14C]lipid in the epididymal and subcutaneous adipose-tissue depots of the meal-fed rats. In contrast, heparin-releasable lipoprotein lipase was not increased in perfused hearts of meal-fed rats on refeeding. Return of meal-fed rats to feeding ad libitum reversed these changes before the restoration of body weight or carcass fat. Evidence is presented that decreased dietary intake rather than meal pattern is an important determinant of the alterations in adipose lipid metabolism in the meal-fed rat in response to a meal.

Download Full-text

Effects of insulin, glucocorticoids and adrenaline on the activity of rat adipose-tissue lipoprotein lipase

Biochemical Journal ◽

10.1042/bj1880185 ◽

1980 ◽

Vol 188 (1) ◽

pp. 185-192 ◽

Cited By ~ 81

Author(s):

P Ashby ◽

D S Robinson

Keyword(s):

Protein Synthesis ◽

Adipose Tissue ◽

Lipoprotein Lipase ◽

Lipase Activity ◽

Lipoprotein Lipase Activity ◽

Fat Bodies ◽

Rat Adipose Tissue ◽

Adipose Tissue Lipoprotein Lipase

The lipoprotein lipase activity of epididymal fat-bodies from starved rats was measured during incubations at 37 degrees C in vitro. Protein synthesis independent activation of the enzyme, previously observed during incubations at 25 decrease C, also occurs at 37 degrees C. Protein-synthesis-dependent increases in the activity of the enzyme occur in the presence of insulin and are markedly potentiated by glucocorticoids. The effects on the activity of the enzyme of insulin alone, or in the presence of glucocorticoids, are correlated with its effects on total protein synthesis in the tissue. Adrenaline antagonizes the increase in activity of the enzyme brought about by insulin and abolishes the potentiation of insulin action by glucocorticoids. These changes may be due, at least in part, to its stimulation of inactivation of the enzyme in the tissue. It is suggested that changes in adipose-tissue lipoprotein lipase activity that occur with changes in nutritional status in vivo result from the combined effects of changes in plasma insulin and glucocorticoid concentrations.

Download Full-text

Effects of exogenous insulin or vanadate on disposal of dietary triacylglycerols between mammary gland and adipose tissue in the lactating rat: insulin resistance in white adipose tissue

Biochemical Journal ◽

10.1042/bj2900557 ◽

1993 ◽

Vol 290 (2) ◽

pp. 557-561 ◽

Cited By ~ 15

Author(s):

T H M Da Costa ◽

D H Williamson

Keyword(s):

Adipose Tissue ◽

Mammary Gland ◽

Lipoprotein Lipase ◽

White Adipose Tissue ◽

Lipase Activity ◽

Dietary Lipid ◽

Lipid Deposition ◽

Exogenous Insulin ◽

Lipoprotein Lipase Activity ◽

Stimulation Of

The effects of exogenous insulin or vanadate (an insulin mimetic) on the disposal of dietary [14C]lipid between oxidation to 14CO2, deposition in adipose tissue or uptake by mammary gland and transfer to suckling pups were studied in virgin and lactating rats. After an oral load of [1-14C]triolein, virgin rats treated with a supraphysiological dose of insulin over 24 h showed a decrease (58%) in 14CO2 production and increased accumulation of [14C]lipid in carcass and white adipose tissue. There was a 2.5-fold increase in lipoprotein lipase activity in the latter. Chronic vanadate administration (12 days) had no effect on these parameters. In lactating rats, the stimulation of the deposition of [14C]lipid in adipose tissue by exogenous insulin was about 10% of that in virgin rats. In prolactin-deficient lactating rats there was no stimulation of [14C]lipid deposition in adipose tissue by insulin. However, both insulin and vanadate treatment increased the accumulation of [14C]lipid in mammary gland to the values seen in the mammary glands plus pups of normal lactating rats. Lipoprotein lipase activity in the gland was also restored to normal values. It is concluded that in lactation there is resistance to insulin stimulation of dietary lipid deposition in adipose tissue, and that this is not due to circulating prolactin. In addition, exogenous insulin plays a role in the regulation of lipoprotein lipase and hence of dietary lipid uptake into lactating mammary gland.

Download Full-text

Lipid Binding of Apolipoprotein CII Is Required for Stimulation of Lipoprotein Lipase Activity Against Apolipoprotein CII–Deficient Chylomicrons

Arteriosclerosis Thrombosis and Vascular Biology ◽

10.1161/01.atv.17.8.1545 ◽

1997 ◽

Vol 17 (8) ◽

pp. 1545-1549 ◽

Cited By ~ 46

Author(s):

Gunilla Olivecrona ◽

Ulrike Beisiegel

Keyword(s):

Lipoprotein Lipase ◽

Lipase Activity ◽

Lipid Binding ◽

Lipoprotein Lipase Activity ◽

Stimulation Of

Download Full-text

Post-translational regulation of lipoprotein lipase activity in adipose tissue

Biochemical Journal ◽

10.1042/bj1760865 ◽

1978 ◽

Vol 176 (3) ◽

pp. 865-872 ◽

Cited By ~ 55

Author(s):

P Ashby ◽

D P Bennett ◽

I M Spencer ◽

D S Robinson

Keyword(s):

Adipose Tissue ◽

Lipoprotein Lipase ◽

Lipase Activity ◽

Translational Regulation ◽

Progressive Increase ◽

Lipoprotein Lipase Activity ◽

Dependent Part ◽

Adipose Tissue Lipoprotein Lipase ◽

Energy Dependent

Changes in adipose-tissue lipoprotein lipase activity that are independent of protein synthesis were investigated in an incubation system in vitro. Under appropriate conditions at 25 degrees C a progressive increase in the enzyme activity occurs that is energy-dependent. Part of the enzyme is rapidly inactivated when the tissue is incubated with adrenaline or adrenaline plus theophylline. The mechanism of this inactivation appears to be distinct from, and to follow, the activation of the enzyme. A hypothesis is presented to account for the results in terms of an activation of the enzyme during obligatory post-translational processing and a catecholamine-regulated inactivation of the enzyme as an alternative to secretion from the adipocyte.

Download Full-text