This paper is only available as a PDF. To read, Please Download here.
Abstract
In mutant analbuminaemic rats (NAR), females demonstrate a more marked hypertriglyceridaemia
than males. Ovariectomy decreases triglyceride levels in female NAR. We measured triglyceride
secretion rates in vivo as well as the activity of acetyl CoA carboxylase (ACC) and
fatty acid synthase (FAS) in hepatic cytosol obtained from female control Sprague-Dawley
(SD) rats and NAR with or without ovariectomy. NAR were severely hyperlipidaemic,
and triglyceride, cholesterol, apolipoprotein A-I and plasma protein concentrations
levels were decreased (all P < 0.01) by ovariectomy. Only triglyceride levels were decreased by ovariectomy in
the SD rats (P < 0.05). Oestradiol treatment in ovariectomized NAR restored plasma protein and triglyceride
concentrations to levels similar to those observed in intact female NAR and caused
a marked increase in plasma cholesterol. Ovariectomy in NAR reduced lipoprotein triglycerides
and cholesterol in VLDL, IDL and LDL1, but had little effect on the triglyceride-cholesterol
ratio of these particles. Both ACC and FAS activities were markedly increased in NAR
vs. SD rats (P < 0.01). This increase was partially corrected by ovariectomy. There was no significant
effect of ovariectomy on ACC or FAS activity in the SD rats. Triglyceride secretion
rates were significantly increased in NAR vs. SD rats (135 ± 10 vs. 103 ± 12 nmol/min
per 100 g body weight; P < 0.05). Ovariectomy markedly decreased triglyceride secretion rate in NAR to 69
± 6 (P < 0.01), but not in SD rats (92 ± 8 nmol/min per 100 g body weight, NS). Oestradiol
treatment in ovariectomized SD rats restored triglyceride levels but had no significant
effect on triglyceride secretion rate (106 ± 23 nmol/min per 100 g). However, oestradiol
treatment in ovariectomized NAR caused a marked increase in plasma triglycerides and
triglyceride secretion rate (188 ± 24 nmol/min per 100 g; P < 0.01). Thus, hypertriglyceridaemia in female NAR is partly determined by a quantitative
increase in the secretion of triglyceride-rich lipoproteins by the liver. The increased
triglyceride secretion is largely dependent on oestrogens because ovariectomy causes
a marked decrease in plasma triglycerides and triglyceride secretion, and oestradiol
treatment restores plasma triglyceride levels to levels normally found in female NAR.
The enhanced secretion is associated with an increase in synthesis of fatty acids
in the liver as assessed by activities of ACC and FAS. These data indicate that there
may be a specific interaction of albumin and oestrogen in the regulation of hepatic
lipid metabolism.
Keywords
To read this article in full you will need to make a payment
Purchase one-time access:
Academic & Personal: 24 hour online accessCorporate R&D Professionals: 24 hour online accessOne-time access price info
- For academic or personal research use, select 'Academic and Personal'
- For corporate R&D use, select 'Corporate R&D Professionals'
Subscribe:
Subscribe to AtherosclerosisAlready a print subscriber? Claim online access
Already an online subscriber? Sign in
Register: Create an account
Institutional Access: Sign in to ScienceDirect
References
- The role of lipids in nephrosclerosis and glomerulosclerosis.Atherosclerosis. 1994; 107: 1
- Renal apolipoproteins in nephrotic rats.Am J Pathol. 1993; 142: 1804
- Glomerular sclerotic lesions in the rat. Histochemical analysis of their macromolecular and cellular composition.Virchows Arch. 1986; 51: 521
- Triglyceride-rich lipoproteins and atherosclerosis, from fast to feast.Ann Med. 1993; 25: 431
- Triglycerides — main risk factor for cardiovascular disease in women?.Acta Med Scand. 1985; 217: 481
- The triglyceride issue: a view from Framingham.Am Heart J. 1986; 112: 432
- Albumin-deficient rat mutant.Science. 1979; 205: 590
- Age-related changes in plasma proteins of analbuminemic rats.Exp Anim. 1983; 32: 123
- Colloid osmotic pressure in young analbuminemic rats.Am J Physiol (Renal Fluid Electrolyte Physiol 26). 1989; 257: F23
- Plasma lipid concentrations and enzyme activities in Nagase analbuminemia rats (NAR).Exp Anim. 1983; 32: 39
- Hyperlipoproteinemia in analbuminemic rats.Atherosclerosis. 1991; 88: 35
- Proteinuria, lipoproteins and renal apolipoprotein deposits in uninephrectomized female analbuminemic rats.Kidney Int. 1995; 47: 442
- The effects of estrogen administration on plasma lipoprotein metabolism in premenopausal females.J Clin Endocrinol Metab. 1983; 57: 262
- Effects of estrogenic compounds on triglyceride kinetics.Metabolism. 1975; 24: 537
- Unusual high-density lipoprotein subclass distribution during late pregnancy.Metabolism. 1993; 42: 1592
- Hypertriglyceridemia: severe type V hyperlipidemia in a young woman.MD Med J. 1992; 41: 231
- Severe hypertriglyceridemia and pancreatitis when estrogen replacement therapy is given to hypertriglyceridemic women.J Lab Clin Med. 1994; 123: 59
- Nagase analbuminemic rats have faster plasma triacylglycerol and VLDL synthesis rates.Biochim Biophys Acta. 1994; 1212: 103
- Hormone levels of anterior pituitary gland and serum in Nagase analbuminemia rats.Endocrinol Japon. 1984; 31: 185
- Fatty acid synthesis and its regulation.Ann Rev Biochem. 1983; 52: 537
- Hyperinsulinemia and in vivo very-low-density lipoprotein-triglyceride kinetics.Am J Physiol (Endocrinol Metab 9). 1984; 246: E187
- Triglyceride kinetics: effects of dietary glucose, sucrose, or fructose alone or with hyperinsulinemia.Am J Physiol (Endocrinol Metab 13). 1986; 250: E325
- Effects of ethanol feeding on hepatic lipid synthesis.Arch Biochem Biophys. 1988; 267: 568
- Measurement of acetyl-CoA carboxylase activity in isolated hepatocytes.Biochim Biophys Acta. 1987; 918: 274
- Characterization of hyperlipoproteinemia in Nagase analbuminemic rats: effects of pravastatin, an HMG-CoA reductase inhibitor, on plasma apolipoproteins, lipoprotein profile and lecithin:cholesterol acyltransferase activity.J Lipid Res. 1991; 32: 1719
- Electroimmunoassay of rat apolipoproteins A-I, A-IV and E. A procedure for sample treatment to increase the sensitivity in diluted fractions.J Lipid Res. 1985; 26: 889
- Some statistical methods useful in circulation research.Circ Res. 1980; 47: 1
- One-way classifications, analysis of variance.in: Statistical Methods. Iowa State University Press, Ames, IA1979: 258-298
- Characterization of hyperlipidemia in Nagase analbuminemic rat (NAR).J Biochem. 1980; 87: 1859
- Extrahepatic lipogenesis contributes to hyperlipidemia in the analbuminemic rat.Am J Physiol (Renal Fluid Electrolyte Physiol 34). 1993; 265: F70
- Proteinuria, not altered albumin metabolism, affects hyperlipidemia in the nephrotic rat.J Clin Invest. 1990; 86: 600
- Plasma lipoprotein cholesterol and endogenous sex hormones in healthy young women.Metabolism. 1989; 38: 1077
- Changes in plasma lipoproteins during various androgen suppression therapies in men with prostatic carcinoma: effects of orchiectomy, estrogen, and combination treatment with luteinizing hormone-releasing hormone agonist and flutamide.J Clin Endocrinol Metab. 1988; 66: 314
- Changes in plasma lipoprotein and apolipoprotein composition in relation to oral versus percutaneous administration of estrogen alone or in cyclic association with urogestan in menopausal women.J Clin Endocrinol Metab. 1991; 73: 373
- Secondary causes of hyperlipidemia.Med Clin North Am. 1994; 78: 117
- Effect of ethinyl estradiol on the secretion of hepatic triglyceride.in: 4th edn. Proc Soc Exp Biol Med. 149. 1975: 181
- Effect of castration on hyperlipidemic, insulin resistant JCR:LA-corpulent rats.Atherosclerosis. 1993; 100: 113
- The free hormone hypothesis: a physiologically based mathematical model.Endocrine Rev. 1989; 10: 232
- Estrogen receptor in the mammalian liver.Science. 1976; 191: 862
- Transport of protein-bound steroid hormones into liver in vivo.Am J Physiol (Endocrinol Metab Gastrointest Physiol 6). 1979; 237: E367
- Variation in hepatic estrogen receptor concentrations in patients with liver disease. A multivariate analysis.Scand J Gastroenterol. 1992; 27: 355
- Effects of serum proteins on estrogen action in the perfused rat liver.Steroids. 1990; 55: 40
Article info
Publication history
Accepted:
February 22,
1995
Received in revised form:
February 16,
1995
Received:
October 11,
1994
Identification
Copyright
© 1995 Published by Elsevier Inc.
