Document Detail


Mode of growth hormone administration influences triacylglycerol synthesis and assembly of apolipoprotein B-containing lipoproteins in cultured rat hepatocytes.
MedLine Citation:
PMID:  9026526     Owner:  NLM     Status:  MEDLINE    
Abstract/OtherAbstract:
Hypophysectomized female rats were treated for 1 week with thyroxine (10 micrograms/kg.day), cortisol (400 micrograms/kg.day), and bovine GH (1 mg/kg.day) either as two daily subcutaneous injections (GH x 2) or as a continuous subcutaneous infusion (GHc) in order to mimic the male and female specific GH secretory patterns, respectively. Hepatocytes were then isolated and kept in short-term cultures. Hypophysectomy decreased the synthesis of triacylglycerol. Treatment with GH x 2 had no or small effects, while GHc normalized the effect of hypophysectomy. ApoB-100 VLDL was assembled before apoB-48 VLDL. ApoB-48 was first assembled as an HDL particle (apoB-48 "HDL"). Hypophysectomy decreased the proportion of intracellular apoB-48 that was recovered as VLDL. Moreover, the proportion of apoB-48 of total apoB in VLDL decreased. Only GHc fully restored the effect of hypophysectomy by inducing an 4-fold increase in the assembly of apoB-48 VLDL, while treatment with GH x 2 gave rise to a 1.8-fold increase. Hypophysectomy resulted in a decrease in the proportion of apoB-48 that was secreted as VLDL and a decrease in the proportion of apoB-48 of total apoB in VLDL. Only treatment with GHc fully restored the secretion of apoB-48 VLDL by inducing an almost 4-fold increase in the secretion of apoB-48 VLDL, while the corresponding value for treatment with GH x 2 was 1.7. However, GH x 2 increased the proportion of the secreted apoB-48 that was recovered in VLDL to the levels found in normal rats and in rats treated with GHc, but this finding was due to a failure of GH x 2 treatment to increase the secretion of apoB-48 "HDL". In summary, a continuous infusion of GH to hypophysectomized rats, mimicking the female secretion of GH, normalized the triacylglycerol synthesis and secretion as well as apoB-48 VLDL assembly and secretion to those levels observed in hepatocyte cultures from intact female rats.
Authors:
A Sjöberg; J Oscarsson; J Borén; S Edén; S O Olofsson
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Publication Detail:
Type:  Journal Article; Research Support, Non-U.S. Gov't    
Journal Detail:
Title:  Journal of lipid research     Volume:  37     ISSN:  0022-2275     ISO Abbreviation:  J. Lipid Res.     Publication Date:  1996 Feb 
Date Detail:
Created Date:  1997-02-20     Completed Date:  1997-02-20     Revised Date:  2006-11-15    
Medline Journal Info:
Nlm Unique ID:  0376606     Medline TA:  J Lipid Res     Country:  UNITED STATES    
Other Details:
Languages:  eng     Pagination:  275-89     Citation Subset:  IM    
Affiliation:
Department of Medical Biochemistry, Góteborg University, Sweden.
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MeSH Terms
Descriptor/Qualifier:
Animals
Apolipoprotein B-100
Apolipoprotein B-48
Apolipoproteins B / metabolism*
Cattle
Cells, Cultured
Female
Glycerol / metabolism
Growth Hormone / administration & dosage*,  pharmacology
Hypophysectomy
Kinetics
Lipoproteins / biosynthesis*
Liver / drug effects,  metabolism*
Oleic Acid / metabolism
Rats
Rats, Sprague-Dawley
Triglycerides / biosynthesis*
Chemical
Reg. No./Substance:
0/Apolipoprotein B-100; 0/Apolipoprotein B-48; 0/Apolipoproteins B; 0/Lipoproteins; 0/Triglycerides; 112-80-1/Oleic Acid; 56-81-5/Glycerol; 9002-72-6/Growth Hormone

From MEDLINE®/PubMed®, a database of the U.S. National Library of Medicine


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