Insulin stimulates synthesis and release of human chorionic gonadotropin by choriocarcinoma cell lines
- Univ. of California School of Medicine, Los Angeles (USA)
Recent studies have shown that insulin regulates placental lactogen, progesterone, and estrogen production from human trophoblast cells. This study was performed to examine whether insulin also regulates the production of hCG by this type of cell. After 24-36 h of preincubation, JEG-3 and JAR cells (2-3 x 10(5) cells/ml.well) or human term trophoblast cells (1 x 10(6) cells/ml.well) were exposed to the test hormone in serum-free Dulbecco's Modified Eagle's Medium for 24-96 h. Secretion of hCG from JEG-3 cells was stimulated by human insulin, human proinsulin, or porcine insulin in a dose-dependent manner, with lowest effective doses of 6.7, 96, and 53 mg/L, respectively. Time-course studies showed that hCG secretion peaked at 72-96 h with insulin exposure; in contrast, no decernable peak was seen without insulin in serum-free media. Exposure of JEG-3 cells for 24 h to 209 mg/liter insulin stimulated hCG synthesis, with 40 +/- 3% more immunoreactive intracellular hCG (P less than 0.05). Cells grown in the presence of insulin and (35S)methionine had 47 +/- 21% more labeled intracellular hCG and 56 +/- 13% more immunoprecipitable (35S)methionine-hCG secreted into the medium than the control cultures (P less than 0.05). During this time period, human placental lactogen release and total trichloroacetice acid-precipitable (35S)methionine protein were not increased. The insulin-induced stimulation of hCG synthesis was inhibited by cycloheximide. Additionally, insulin did not significantly affect total intracellular protein during 24-96 h of incubation. Insulin also increased hCG release from JAR cells, but not from human term trophoblast cells. A mouse monoclonal antibody to the IGF-I receptor inhibited the stimulation of insulin in JEG-3 cells.
- OSTI ID:
- 5922250
- Journal Information:
- Endocrinology; (USA), Vol. 128:3; ISSN 0013-7227
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
GONADOTROPINS
SECRETION
INSULIN
BIOCHEMICAL REACTION KINETICS
CARCINOMAS
DOSE-RESPONSE RELATIONSHIPS
MAN
METHIONINE
SULFUR 35
SWINE
TRACER TECHNIQUES
TUMOR CELLS
AMINO ACIDS
ANIMAL CELLS
ANIMALS
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBOXYLIC ACIDS
DAYS LIVING RADIOISOTOPES
DISEASES
DOMESTIC ANIMALS
DRUGS
EVEN-ODD NUCLEI
HORMONES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
LIGHT NUCLEI
LIPOTROPIC FACTORS
MAMMALS
NEOPLASMS
NUCLEI
ORGANIC ACIDS
ORGANIC COMPOUNDS
ORGANIC SULFUR COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
PRIMATES
RADIOISOTOPES
REACTION KINETICS
SULFUR ISOTOPES
VERTEBRATES
550201* - Biochemistry- Tracer Techniques
550901 - Pathology- Tracer Techniques