Signaling pathway involved in the pro-apoptotic effect of dopamine in the GH3 pituitary cell line

Area of Science:

• Neuroendocrinology
• Cell Biology
• Biochemistry

Background:

• Dopamine (DA) is a neurotransmitter with known apoptotic effects in the central nervous system, mediated by the dopamine transporter (DAT) and reactive oxygen species (ROS).
• While DA inhibits prolactin in the pituitary, its pro-apoptotic role in pituitary cells, specifically mammosomatotropes, is not well understood.

Purpose of the Study:

• To investigate the pro-apoptotic effect of dopamine (DA) in the GH3 mammosomatotrope cell line.
• To elucidate the specific molecular mechanisms by which DA induces apoptosis in these pituitary cells.

Main Methods:

• Utilized flow cytometry, Western blot, and confocal microscopy to assess apoptosis markers.
• Quantified intracellular reactive oxygen species (ROS) formation.
• Employed dopamine transporter (DAT) inhibitors and the antioxidant N-acetyl-L-cysteine (NAC).

Main Results:

• Dopamine (DA) induced significant apoptosis in GH3 cells, evidenced by loss of mitochondrial potential, Bax relocation, cytochrome c release, caspase-3 activation, and nuclear fragmentation.
• Dopamine transporter (DAT) expression was confirmed in GH3 cells, and DAT inhibition reversed DA-induced apoptosis.
• DA rapidly increased intracellular ROS, which was blocked by NAC, indicating a key role for oxidative stress.

Conclusions:

• Dopamine (DA) triggers apoptosis in pituitary GH3 cells via a mechanism involving the dopamine transporter (DAT) and oxidative stress.
• The findings suggest that ROS generated by DA targets the mitochondrial transition pore, leading to cell death.
• This study provides the first evidence of DA-induced apoptosis in pituitary cells, with potential implications for understanding lactotrope apoptosis.