Morphological evidence of lysosomal uptake of high-density lipoproteins by rat adrenocortical cells in vitro

Tóth, István János; Szabó, Dénes; Bácsy, E; Szalay, Katalin Sz.; Hesz, A; Szollár, Lajos

doi:10.1016/0303-7207(86)90062-6

Cited by 11 publications

(10 citation statements)

References 38 publications

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“…Studying the internalization of HDL or LDL by adrenocortical cells, in vitro, in different functional states, by morphological methods, we showed that many HDL binding sites are located on the microvilli of rat adrenocortical cells and numerous LDL receptors are situated on the microvilli of Y-1 cells (Tóth, 1992;Tóth et al, 1992). The majority of HDL binding sites have been found to locate on the microvilli of the quiescent or hormone-stimulated dispersed zona glomerulosa and zona fasciculata cells following incubations with HDL-Au particles (Tóth, 1992;Tóth et al, 1986). By applying both affinity and immunocytochemistry simultaneously, e.g., by incubating the cells first with HDL-Au (20-22 nm colloidal gold) and then processing them for cryo-immunoelectron microscopy (5 nm immunogold, representing Apo A-I epitopes), we found the two labels often co-localized on microvillar membranes.…”

Section: Microvilli: Interactionmentioning

confidence: 99%

“…L, Lipid droplet; mv, microvilli; lys, lysosome; L-lys, lipid-lysosome complex; cry, cholesterol crystal. The cells, derived from rats that received daily intramuscular injections of 30 µg ACTH for 2 weeks, were incubated for 5 hours at 37°C in the presence of HDL-Au (about 70 µg/ml protein) and then processed for electron microscopy (Tóth et al, 1986). matrix (Figs.…”

Section: Hdl Effect On Chronicallymentioning

confidence: 99%

“…D: Electron micrograph of isolated zona fasciculata cells, exhibiting typical, slightly more electron lucent lipid droplets, which reflects the different chemical composition of these lipids. ZG, Zona glomerulosa; ZF, zona fasciculata; L or lip, lipid droplet; cry, crystalshaped body; arrows, non-specific esterase reaction in lysosomes (see methods in Szabó et al, 1984 andTóth et al, 1986). A,B, and D reproduced from Szabó et al, 1984, with permission of the publisher.…”

Section: Introductionmentioning

confidence: 98%

“…L, Lipid droplets; m, mitochondrion; lys, lysosome. Cell suspensions from the zona glomerulosa were incubated for 5 hours at 37°C with native HDL or HDL-Au (about 70 µg/ml protein) in the presence or absence of 1.3 3 10 27 M a-MSH and processed for electron microscopy (Tóth et al, 1986). Reproduced from Tóth et al, 1987, with permission of the publisher.…”

Section: Introductionmentioning

confidence: 99%

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Lipoproteins, lipid droplets, lysosomes, and adrenocortical steroid hormone synthesis: Morphological studies

Tóth

Szabó

Bruckner

1997

Microsc. Res. Tech.

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Section: Microvilli: Interactionmentioning

confidence: 99%

Section: Hdl Effect On Chronicallymentioning

confidence: 99%

Section: Introductionmentioning

confidence: 98%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Lipoproteins, lipid droplets, lysosomes, and adrenocortical steroid hormone synthesis: Morphological studies

Tóth

Szabó

Bruckner

1997

Microsc. Res. Tech.

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“…Gold-HDL conjugates were prepared according to Toth et al (1986). Colloidal gold particles 8.8 nm in diameter were purchased from Sigma.…”

Section: Internalization Of Colloidal Gold Labelled Hdl (Gold-hdl)mentioning

confidence: 99%

Effect of lipoproteins on cholesterol synthesis in rat Sertoli cells

Maboundou

Fofana²,

Fresnel³

et al. 1995

Biochem. Cell Biol.

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Lipoprotein metabolism has been investigated in cultured rat Sertoli cells. Cells incubated with low-density lipoproteins (LDLs) or high-density lipoproteins (HDLs) showed a concentration-dependent decrease of sterol synthesis, indicating a net cholesterol delivery to the Sertoli cells. At 50 micrograms/mL, lipoproteins inhibited the incorporation of [14C]acetate into free cholesterol by 83% for the LDL and 47% for the HDL. Electron microscopic examinations of the Sertoli cells provide evidence of the internalization of gold-labelled HDL into coated pits and coated vesicles. Competitive studies between human LDL and rat HDL indicate that Sertoli cells take up cholesterol from LDL and HDL containing apolipoprotein (apo) E by common pathways. These results suggest that Sertoli cells possess apo B and E receptors for the uptake and degradation of LDL and HDL, although the basement membrane excludes the passage of LDL from blood capillaries to the Sertoli cells. At 50 micrograms/mL, apo-E-depleted HDL inhibited the incorporation of [14C]acetate into free cholesterol by 34%. Thus, this study shows that Sertoli cells are capable of taking up apo-E-depleted HDL cholesterol for cell metabolism.

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Hepatic metabolism of colloidal gold-low-density lipoprotein complexes in the rat: Evidence for bulk excretion of lysosomal contents into bile

1989

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Rats were treated with 17 alpha-ethinyl estradiol to induce high levels of low-density lipoprotein receptors in hepatocytes. When these rats were given intravenous injections of low-density lipoprotein-colloidal gold complexes, most of the gold (labeled with 195Au) appeared to be taken up by Kupffer cells, as were complexes of colloidal gold with albumin or polyvinylpyrrolidone. However, when these rats were also administered gadolinium chloride, which blocks Kupffer cell activity, most of the low-density lipoprotein-gold (but not gold complexed with albumin or polyvinylpyrrolidone) was taken up into hepatocytes by receptor-mediated endocytosis and concentrated in peribiliary lysosomes, as determined by electron microscopy. Colloidal gold taken up as a complex with low-density lipoprotein was excreted into the feces via the common bile duct at a maximal rate of about 5% daily, 4 to 12 days after injection. Thereafter, the rate of gold excretion fell off until reaching a plateau after 3 weeks. At this late time, most of the colloidal gold was shown by electron microscopy to be in Kupffer cells, whereas earlier (6 days after injection) it was contained mainly in older hepatocytic lysosomes, identified by lipofuscin granules. It is concluded that, in rats, hepatocytic lysosomes empty most of their contents into bile every week or two, apparently by exocytosis.

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Morphological evidence of lysosomal uptake of high-density lipoproteins by rat adrenocortical cells in vitro

Cited by 11 publications

References 38 publications

Lipoproteins, lipid droplets, lysosomes, and adrenocortical steroid hormone synthesis: Morphological studies

Lipoproteins, lipid droplets, lysosomes, and adrenocortical steroid hormone synthesis: Morphological studies

Effect of lipoproteins on cholesterol synthesis in rat Sertoli cells

Hepatic metabolism of colloidal gold-low-density lipoprotein complexes in the rat: Evidence for bulk excretion of lysosomal contents into bile

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