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 Tools annual

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 monthly

Global: Zendy Plus monthly

Presents the access of premium content as premium feature

Premium Content

Global: Zendy Plus annual

Global: Zendy Free Plan

Low-density lipoproteins (LDL) receptor activity, as reflected by LDL degradation, was stimulated by the addition of insulin to cultures of human skin fibroblasts. These changes occurred independently of the glucose concentration of the incubation medium and occurred whether or not LDL receptor activity was suppressed. A comparison of the saturation kinetics of LDL receptor activity in the presence and absence of insulin indicated that insulin produced a 35% increase in Vmax with no difference in "apparent Km". These results suggest that insulin enhances LDL receptor activity by increasing the number of LDL receptors rather than by influencing binding affinity. In confirmation, LDL degradation by receptor negative cells was not enhanced by insulin. Sterol synthesis from [14C]acetate was also stimulated by insulin, but egress of cholesterol and cellular cholesterol content were unaffected by the hormone. The effect of insulin on LDL receptors was not dependent on its known ability to enhance cellular DNA synthesis and proliferation, because insulin stimulated LDL receptor activity in cells kept quiescent by maintenance in plasma-derived serum that was devoid of platelet derived growth factor. Nevertheless, the effect of insulin in enhancing LDL receptor number, coupled with stimulation of endogenous cholesterol synthesis, provides a mechanism whereby the cell could theoretically increase its supply of cholesterol during times of additional need.

Low-density lipoprotein receptor activity in cultured human skin fibroblasts. Mechanism of insulin-induced stimulation.