Effect of intravenous dopamine infusion on pituitary and thyroid function and on nephroprotection

Abstract

82D 1 and D 5 ), dopamine activates subunit Gs of protein G and indirectly stimulates adenylate cyclase. 1 On the other hand, activation of receptors belonging to the D 2 -like family (D 2 , D 3 , and D 4 ) leads to the inhibition of protein G and adenylate cyclase and triggers sodium channels. 1,2 Due to the large numbers of dopamine receptors distributed throughout the CNS, endogenous dopamine has the ability to regulate a broad range of physio logical functions such as locomotion and cognition. Dopamine also plays an important role in neurohormonal regulation, modulates renal function, and the function of gastrointestinal and cardiovascular systems. 3 Generally, dopamine does not cross the blood-brain barrier; AbstrAct IntroductIon Catecholamines, including dopamine, are used in cardiac intensive care. objectIves The aim of the study was to assess the effect of intravenous dopamine infusion on the function of pituitary gland in patients with acute cardiac failure. We analyzed changes in the serum levels of thyroid-stimulating hormone (TSH) and adrenocorticotropic hormone (ACTH), as well as potential nephroprotection. PAtIents And methodsThe study involved 29 patients with chronic decompensated heart failure (New York Heart Association class III/IV; mean age 77.4 ±13.3 years). Dopamine was administered intravenously in doses varying from 1 to 5 μg/kg/min. Measurements of TSH, free triiodothyronine (FT 3 ), free thyroxine (FT 4 ), and ACTH were taken directly before dopamine infusion, after 12 hours of continuous infusion, and 12 hours after the 72-hour infusion was completed.results Serum FT 3 levels were significantly higher before dopamine infusion than at 12 hours post infusion (5.12 ±1.16 vs. 4.27 ±0.89 pmol/l, P <0.005). Serum FT 4 levels before the infusion were significantly higher than after 12 hours of continuous infusion as well as after 12 hours post infusion (18.79 ±5.33 vs. 17.06 ±4.61 pmol/l, P <0.05; 18.79 ±5.33 vs. 16.26 ±4.53 pmol/l, P <0.05, respectively). There were no statistically significant differences between serum TSH and ACTH levels or in creatinine clearance before, during, and 12 hours post infusion.conclusIons Intravenous infusion of dopamine may downregulate endocrine thyroid function; however, it has no significant effect on the pituitary gland-derived TSH and ACTH. There was no significant nephroprotective effect of low-dose dopamine infusion in patients with chronic decompensated chronic heart failure.IntroductIon Catecholamines are commonly used in intensive care. They help maintain vital body functions by increasing peripheral blood flow. Synthetic epinephrine, norepinephrine, dopamine, and dobutamine are the most common catecholamines in the clinical setting. The population of patients diagnosed with advanced heart failure and episodes of decompensation is on the rise, as is the use of catecholamines in cardiology practice.Dopaminergic neurons located in the central nervous system (CNS) are the main source of dopamine. Depending on the type of receptors, dopamine can exert ei...