Effect of chronic ACTH treatment on the physical state of lipid droplets in rat adrenocortical cells

D. Szabó, F. Czakó, I. E. Tóth, K. Sz Szalay, K. Krasznai, E. Stark

Research output: Contribution to journalArticle

2 Citations (Scopus)

Abstract

A histophysical method has been adapted to determine the thermotropic phase transitions of adrenocortical lipid droplets using a polarizing microscope equipped with a cold/hot stage. Cryosections of freshly-removed, unfixed adrenals, derived from control (untreated), and 14 days ACTH-treated rats were examined. The lipid droplets in the zona fasciculata and zona reticularis of the untreated rats were birefringent at room temperature (22°C). The birefringence of zona glomerulosa lipids selectively increased in the temperature range from -10 to -15°C. In cryosections prepared from ACTH-treated rats, thermotropic phase transitions of the lipid droplets appeared at a temperature range between -30 and -40°C in each cortical zone. The chemical analysis of the isolated lipids revealed that the relative amount of triglycerides in the zona fasciculata lipids increased, while that of free and esterified cholesterol decreased after chronic ACTH treatment. Present data suggest that the increased fluidity of lipid droplets promotes lipid mobilization in response to the enhanced demand of the chronically stimulated adrenocortical cells. Viscosity-dependent mobilization of free cholesterol from lipid droplets is not a rate-limiting process in adrenal steroidogenesis, but rather may represent an important control of the availability of precursor from lipid stores.

Original languageEnglish
Pages (from-to)781-784
Number of pages4
JournalJournal of Steroid Biochemistry and Molecular Biology
Volume41
Issue number3-8
DOIs
Publication statusPublished - Mar 1992

ASJC Scopus subject areas

  • Endocrinology, Diabetes and Metabolism
  • Biochemistry
  • Molecular Medicine
  • Molecular Biology
  • Endocrinology
  • Clinical Biochemistry
  • Cell Biology

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