Localization and movement of newly synthesized cholesterol in rat ovarian granulosa cells

Journal Article · Fri Jul 01 04:00:00 EDT 1988 · Endocrinology; (United States)

DOI:https://doi.org/10.1210/endo-123-1-81· OSTI ID:6908844

Lange, Y; Schmit, V M; Schreiber, J R

The distribution and movement of cholesterol were studied in granulosa cells from the ovaries of estrogen-stimulated hypophysectomized immature rats cultured in serum-free medium. Plasma membrane cholesterol was distinguished from intracellular cholesterol with cholesterol oxidase, an enzyme that converts cell surface cholesterol to cholestenone, leaving intracellular cholesterol untouched. Using this approach we showed that 82% of unesterified cholesterol was associated with the plasma membrane in granulosa cells cultured for 48 h in serum-free medium in both the presence and absence of added androstenedione and FSH. FSH and androstenedione stimulated a marked increase in steroid hormone (progestin) production. The movement of newly synthesized cholesterol to the plasma membrane also was followed using cholesterol oxidase. Newly synthesized cholesterol reached the plasma membrane too rapidly to be measured in unstimulated cells (t1/2 less than 20 min); however, in cells stimulated by FSH and androstenedione, this rate was considerably slower (t1/2 approximately 2h). Therefore, cholesterol movement to the plasma membrane appears to be regulated by gonadotropins in these cells. We tested whether steroid biosynthesis used all cell cholesterol pools equally. To this end we administered (3H)acetate and (14C)acetate at different times and determined their relative specific contents in various steroids after defined intervals. The relative ages of the steroids (youngest to oldest) were: lanosterol, progestins, intracellular cholesterol, and plasma membrane cholesterol. This finding suggests that progestins use newly synthesized intracellular cholesterol in preference to preexisting intracellular or cell surface cholesterol.

• Research Organization: Rush Medical College, Chicago, IL (USA)
• OSTI ID: 6908844
• Journal Information: Endocrinology; (United States), Journal Name: Endocrinology; (United States) Vol. 123:1; ISSN ENDOA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETATES
ANDROGENS
ANDROSTANES
ANDROSTENEDIONE
ANIMAL CELLS
ANIMALS
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL LOCALIZATION
BIOSYNTHESIS
BODY
CARBON 14 COMPOUNDS
CARBOXYLIC ACID SALTS
CELL CONSTITUENTS
CELL CULTURES
CELL MEMBRANES
CHOLESTEROL
ENZYMES
FEMALE GENITALS
FSH
GONADOTROPINS
GONADS
HORMONES
HYDROXY COMPOUNDS
ISOTOPE APPLICATIONS
KETONES
KINETICS
LABELLED COMPOUNDS
MAMMALS
MEMBRANES
ORGANIC COMPOUNDS
ORGANS
OVARIES
OXIDOREDUCTASES
PEPTIDE HORMONES
PITUITARY HORMONES
RATS
REACTION KINETICS
RODENTS
STEROID HORMONES
STEROIDS
STEROLS
SYNTHESIS
TRACER TECHNIQUES
TRITIUM COMPOUNDS
VERTEBRATES