Onset of lipoprotein-supported steroidogenesis in differentiating granulosa cells of rats: cellular events involved in mediating FSH-enhanced uptake of low-density lipoproteins

Thesis/Dissertation · Thu Jan 01 00:00:00 EST 1987

OSTI ID:6905350

Foster, J D

Luteal cells use lipoproteins as the main source of cholesterol in steroidogenesis. However, little is known about the mechanisms underlying hormonal control of lipoprotein uptake. Thus, the authors tested the hypothesis that FSH and androgens regulate low density lipoprotein (LDL)-supported steroidogenesis in maturing granulosa cells by affecting receptor-mediated endocytosis of LDL at a cellular level. For this, immature ovarian granulosa cells were cultured with or without hormones, compactin (de novo synthesis inhibitor), or unlabeled or labeled (/sup 125/I or gold particles) LDL. Nonhormone-treated cultures produced little progestin; FSH and FSH/androstenedione stimulated steroid secretion. Progestin production by hormone-, but not nonhormone-, treated cultures was decreased by compactin, suggesting that de novo synthesis provided sterol for steroidogenesis. EM quantitation of cells exposed to gold-LDL at 37/sup 0/C revealed that, compared to nonhormone-treated cells, FSH-treated cells (1) bound and internalized more gold-LDL, (2) had a smaller percentage of gold-LDL at their surfaces, (3) displayed a faster apparent rate of LDL internalization and delivery to lysosomes, and (4) contained more gold-labeled lysosomes. Data from biochemical studies in which /sup 125/I-LDL was used supported the morphological findings. In conclusion, this study demonstrates that FSH has important effects at the cellular level on LDL uptake, which seem to underlie the striking increase in progestin production accompanying granulosa cell differentiation.

• Research Organization: Temple Univ., Philadelphia, PA (USA)
• OSTI ID: 6905350
• Resource Relation: Other Information: Thesis (Ph. D.)
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
FISHES
BIOLOGICAL EFFECTS
IODINE 125
UPTAKE
LIPOPROTEINS
ANIMAL CELLS
BIOCHEMISTRY
CELL DIFFERENTIATION
CHOLESTEROL
ELECTRON MICROSCOPY
GOLD COMPLEXES
IN VITRO
LYSOSOMES
OVARIES
PHAGOCYTOSIS
ANIMALS
AQUATIC ORGANISMS
BETA DECAY RADIOISOTOPES
BODY
CELL CONSTITUENTS
CHEMISTRY
COMPLEXES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
FEMALE GENITALS
GONADS
HYDROXY COMPOUNDS
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPES
LIPIDS
MICROSCOPY
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
ORGANOIDS
ORGANS
PROTEINS
RADIOISOTOPES
STEROIDS
STEROLS
TRANSITION ELEMENT COMPLEXES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques