1. The precise effects of insulin, dexamethasone and lipogenic precursors on the secretion of very-low-density lipoprotein (VLDL) cholesterol and triacylglycerol were dependent on the age of the culture and the duration of treatment. 2. The rates of secretion of triacylglycerol and cholesterol gradually declined with the age of the culture, although there was no detectable decrease within a given 24 h period. 3. Between 4 h and 24 h after cell preparation, insulin inhibited VLDL secretion. Inhibition was maximal between 6 and 12 h after addition of insulin. Longer-term treatment (24-48 h) with insulin resulted in a stimulation of VLDL secretion. This effect was less apparent when dexamethasone was simultaneously present. The secretion of triacylglycerol and cholesteryl ester was more sensitive to insulin than was that of non-esterified cholesterol. 4. Dexamethasone alone stimulated the secretion of VLDL to an extent which increased with the age of the culture. In young cultures (up to 24 h old) dexamethasone protected against inhibition by insulin, but was ineffective in older cultures. 5. In young cultures the stimulatory effect of lipogenic precursors (lactate and pyruvate) on the secretion of triacylglycerol and cholesterol was more pronounced in the presence of dexamethasone. In cultures older than 24 h, the secretion of these components was less sensitive to short-term stimulation by lactate and pyruvate.
Skip Nav Destination
Article navigation
January 1988
-
Cover Image
Cover Image
- PDF Icon PDF LinkFront Matter
- PDF Icon PDF LinkTable of Contents
- PDF Icon PDF LinkAdvertising
Research Article|
January 01 1988
Short- and longer-term regulation of very-low-density lipoprotein secretion by insulin, dexamethasone and lipogenic substrates in cultured hepatocytes. A biphasic effect of insulin
S M Bartlett;
S M Bartlett
1Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford, U.K.
Search for other works by this author on:
G F Gibbons
G F Gibbons
1Nuffield Department of Clinical Medicine, Radcliffe Infirmary, Oxford, U.K.
Search for other works by this author on:
Publisher: Portland Press Ltd
Online ISSN: 1470-8728
Print ISSN: 0264-6021
© 1988 London: The Biochemical Society
1988
Biochem J (1988) 249 (1): 37–43.
Citation
S M Bartlett, G F Gibbons; Short- and longer-term regulation of very-low-density lipoprotein secretion by insulin, dexamethasone and lipogenic substrates in cultured hepatocytes. A biphasic effect of insulin. Biochem J 1 January 1988; 249 (1): 37–43. doi: https://doi.org/10.1042/bj2490037
Download citation file:
Sign in
Don't already have an account? Register
Sign in to your personal account
You could not be signed in. Please check your email address / username and password and try again.
Could not validate captcha. Please try again.