Elevated SNSA induces dysglycemia by enhancing adipose lipolysis and stimulating hepatic glucose production. It also promotes cardiovascular disease (CVD) by multiple mechanisms including augmenting systemic and vascular reactive oxygen and nitrogen species (ROS, RNS) generation. Elevated plasma prolactin (subclinical hyperprolactinemia) has also been associated with systemic inflammation, which can potentiate dysglycemia and CVD. BQR, the only dopamine agonist approved for treatment of T2D, improves postprandial dysglycemia and reduces CVD events. To evaluate mechanisms for the glucose lowering and CVD protective effects of BQR, we evaluated BQR’s effect on plasma markers of SNSA and ROS/RNS and plasma prolactin and leptin from a mechanistic study in which BQR added to 15 T2D subjects (HbA1c 8.3%) treated with a GLP-1 RA significantly improved HbA1c (-0.6%), postprandial hyperglycemia (by 22%) and endothelial dysfunction (by 36%). Plasma norepinephrine (NE), normetanephrine (NM), TBAR (a marker of systemic OS), nitrotyrosine (NT, a marker of systemic oxidative/nitrosative stress), prolactin and leptin were measured at baseline and after 4 months of BQR add-on therapy (3.2 mg/day). Plasma NE, NM, TBAR, NT and prolactin levels were elevated at baseline and decreased significantly with BQR [NE by 33% (2.95 to 1.95 ng/mL, p <0.0005); NM by 22% (56.5 to 44.3 pg/ml, p<0.018); TBAR by 10% (10.2 to 9.2 μM, p=0.04); NT by 13% (214 to 187 nM, p<0.02); prolactin by 42% (13.0 to 7.6 ng/ml, p<0.012)]. Plasma leptin, unchanged in the whole group, decreased 23% (35.7 to 27.5 ng/mL, p=0.038) in subjects with elevated leptin (>20 ng/dl, N=7) at baseline.
Conclusion: Bromocriptine-QR is the only T2D therapy known to simultaneously reduce elevated plasma NE, NM, prolactin and OS and such actions may be important for the drug’s glucose lowering and CVD protective effects.
B. Chamarthi: Employee; Self; VeroScience LLC. E. Cersosimo: None. J.M. Adams: None. M. Alatrach: None. C. Agyin: None. C.L. Triplitt: Consultant; Self; Abbott. Speaker's Bureau; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Eli Lilly and Company, Janssen Pharmaceuticals, Inc. M. Ezrokhi: Employee; Self; VeroScience LLC. S. Luo: Employee; Self; VeroScience LLC. E. Duvallet: Employee; Self; VeroScience LLC. A.H. Cincotta: Employee; Self; VeroScience LLC. R.A. DeFronzo: Advisory Panel; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Elcelyx Therapeutics, Inc., Intarcia Therapeutics, Inc., Janssen Pharmaceuticals, Inc., Novo Nordisk Inc. Research Support; Self; AstraZeneca, Boehringer Ingelheim Pharmaceuticals, Inc., Janssen Pharmaceuticals, Inc., Merck & Co., Inc. Speaker's Bureau; Self; AstraZeneca, Novo Nordisk Inc.