In vitro evidence of glucose-induced toxicity in GnRH secreting neurons: high glucose concentrations influence GnRH secretion, impair cell viability, and induce apoptosis in the GT1-1 neuronal cell line.
OBJECTIVE
To evaluate for direct toxic effects of high glucose concentrations on cellular physiology in GnRH secreting immortalized GT1-1 neurons.


METHODS
Prospective experimental design.


METHODS
In vitro experimental model using a cell culture system.


METHODS
GT1-1 cells were cultured in replicates in media with two different glucose concentrations (450 mg/dL and 100 mg/dL, respectively) for varying time intervals (24, 48, and 72 hours).


METHODS
Effects of glucose concentrations on GnRH secretion by the GT1-1 neurons were evaluated using a static culture model. Cell viability, cellular apoptosis, and cell cycle events in GT1-1 neurons maintained in two different glucose concentrations were assessed by flow cytometry (fluorescence-activated cell sorter) using Annexin V-PI staining.


RESULTS
Adverse influences of high glucose concentrations on GnRH secretion and cell viability were noted in cultures maintained in high glucose concentration (450 mg/dL) culture medium for varying time intervals. A significantly higher percentage of cells maintained in high glucose concentration medium demonstrated evidence of apoptosis by a fluorescence-activated cell sorter.


CONCLUSIONS
We provide in vitro evidence of glucose-induced cellular toxicity in GnRH secreting GT1-1 neurons. Significant alterations in GnRH secretion, reduced cell viability, and a higher percentage of apoptotic cells were observed in GT1-1 cells maintained in high (450 mg/dL) compared with low (100 mg/dL) glucose concentration culture medium.
Pal
Lubna
L
Department of Obstetrics, Gynecology & Women's Health, Albert Einstein College of Medicine, Bronx, New York, USA. lubnapal@aol.com
Chu
Hsiao-Pai
HP
Shu
Jun
J
Topalli
Ilir
I
Santoro
Nanette
N
Karkanias
George
G
D000818:Animals; D017209:Apoptosis / Q000187:drug effects* / Q000502:physiology; D002460:Cell Line; D002461:Cell Line, Transformed; D002470:Cell Survival / Q000187:drug effects / Q000502:physiology; D005947:Glucose / Q000633:toxicity*; D007987:Gonadotropin-Releasing Hormone / Q000378:metabolism*; D051379:Mice; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism*; D011446:Prospective Studies
D007987:Gonadotropin-Releasing Hormone; D005947:Glucose