The LDL receptor is not necessary for acute adrenal steroidogenesis in mouse adrenocortical cells

Am J Physiol Endocrinol Metab. 2007 Feb;292(2):E408-12. doi: 10.1152/ajpendo.00428.2006. Epub 2006 Sep 19.

Abstract

Steroid hormones are synthesized using cholesterol as precursor. To determine the functional importance of the low density lipoprotein (LDL) receptor and hormone-sensitive lipase (HSL) in adrenal steroidogenesis, adrenal cells were isolated from control, HSL(-/-), LDLR(-/-), and double LDLR/HSL(-/-) mice. The endocytic and selective uptake of apolipoprotein E-free human high density lipoprotein (HDL)-derived cholesteryl esters did not differ among the mice, with selective uptake accounting for >97% of uptake. In contrast, endocytic uptake of either human LDL- or rat HDL-derived cholesteryl esters was reduced 80-85% in LDLR(-/-) and double-LDLR/HSL(-/-) mice. There were no differences in the selective uptake of either human LDL- or rat HDL-derived cholesteryl esters among the mice. Maximum corticosterone production induced by ACTH or dibutyryl cyclic AMP and lipoproteins was not altered in LDLR(-/-) mice but was reduced 80-90% in HSL(-/-) mice. Maximum corticosterone production was identical in HSL(-/-) and double-LDLR/HSL(-/-) mice. These findings suggest that, although the LDL receptor is responsible for endocytic delivery of cholesteryl esters from LDL and rat HDL to mouse adrenal cells, it appears to play a negligible role in the delivery of cholesterol for acute adrenal steroidogenesis in the mouse. In contrast, HSL occupies a vital role in adrenal steroidogenesis because of its link to utilization of selectively delivered cholesteryl esters from lipoproteins.

Publication types

  • Research Support, N.I.H., Extramural
  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adrenal Cortex / cytology
  • Adrenal Cortex / metabolism*
  • Animals
  • Cells, Cultured
  • Cholesterol Esters / metabolism
  • Corticosterone / biosynthesis
  • Humans
  • Mice
  • Mice, Inbred C57BL
  • Mice, Knockout
  • Rats
  • Receptors, LDL / genetics
  • Receptors, LDL / physiology*
  • Steroids / biosynthesis*
  • Sterol Esterase / genetics
  • Sterol Esterase / physiology

Substances

  • Cholesterol Esters
  • Receptors, LDL
  • Steroids
  • Sterol Esterase
  • Corticosterone