MMQ Cells

The MMQ cell line is a clonal, prolactin-secreting cell line derived from the 7315a rat pituitary tumor. It exclusively secretes prolactin and expresses functional dopamine receptors, specifically of the D2 subtype. Dopamine inhibits prolactin (PRL) release by reducing intracellular cyclic AMP (cAMP) levels and calcium uptake, as demonstrated in various experiments. This inhibition is reversed by haloperidol and pertussis toxin, confirming the role of GTP-binding proteins in dopamine's action. MMQ cells are also responsive to somatostatin (SRIF) and vasoactive intestinal polypeptide (VIP), but not to TRH, angiotensin II, or neurotensin. MMQ cells proliferate rapidly, doubling in less than 24 hours under optimal conditions. When transplanted into rats, MMQ cells form tumors that increase serum prolactin levels without altering other hormones such as ACTH. This cell line is an important model for studying prolactin regulation, particularly in relation to dopamine and its inhibitory mechanisms on prolactin secretion.