English (United Kingdom)

https://curated-unify.zendy.io/wp-json/zendy-region/v1/featured_content/oa?rat=en

https://curated-unify.zendy.io/wp-json/zendy-region/v1/highlighted_journal/

Global: Zendy Plus annual

Presents the access of premium content as premium feature

Premium Content

Presents the keyphrase highlighting as premium feature

Keyphrase Highlighting

Presents the summarisation as premium feature

Summarisation

Insights

Presents the pdf analysis as premium feature

PDF Analysis

Presents the zaia usage as premium feature

ZAIA

Global: Zendy Tools annual

Global: Zendy Free Plan

Global: Zendy Tools monthly

Global: Zendy Plus monthly

We have compared the rates of low density lipoprotein (LDL) uptake and cholesterol synthesis in the rat intestine. By using a constant infusion technique, total and receptor-independent uptake was determined with homologous rat LDL (rLDL) and methylated human LDL (Me-hLDL), respectively. The absolute rates of sterol synthesis were measured with [1-(14) C]-octanoate and [3H]water. The rates of rLDL uptake in whole gut segments were similar along the length of the small intestine, whereas the rates of sterol synthesis varied over a 5-fold range and were highest in the duodenum and distal ileum. When the mucosal epithelium was fractionated along the villus/crypt axis, both rLDL and Me-hLDL clearance by the enterocytes increased approximately 3-fold in going from the upper villus to the crypt cell fractions, in both jejunum and ileum. In both the whole gut segments and isolated cells, approximately 60% of LDL uptake was receptor dependent. When the rates of rLDL cholesterol uptake were calculated and related to the absolute rates of sterol synthesis in the same cell fractions in vivo, both processes were found to be distributed similarly along the villus/crypt axis. Furthermore, the majority of mucosal cholesterol (64-86%) was derived from local synthesis rather than from rLDL uptake at all locations along the intestinal villus. Finally, when sterol synthesis in the epithelial cells was varied up to 7-fold by feeding cholesterol, triglyceride, cholestyramine, or surfomer, rLDL uptake was essentially unchanged. Thus, in intestinal epithelial cells in vivo, the rate of LDL uptake was constant under circumstances in which changing needs for cellular cholesterol were met by changes in the rates of sterol synthesis.

Cholesterol synthesis and low density lipoprotein uptake are regulated independently in rat small intestinal epithelium.