ABSTRACT
OBJECTIVE: Renal and cardiovascular function is improved during the first 24 hours of life in preterm ventilated baboons exposed to prenatal betamethasone (BETA). We hypothesized BETA-induced effects would be sustained through day 6 of life. Study design Pregnant baboons received saline or BETA (6 mg) 48 and 24 hours before preterm delivery at 125 days' gestation. The newborn baboons were ventilated for 6 days, and assessed for renal, cardiovascular, and endocrine function. RESULTS: Mean arterial blood pressure (MAP) and glomerular filtration rate (GFR) values 24 hours after delivery were higher in the BETA group. Kidney Na, K-ATPase activity was higher in the BETA group by day 6. All other measures were similar in both groups by day 6. CONCLUSION: Prenatal BETA exposure in the premature baboon: (1) increases MAP and GFR on day 1 without measurable effects by day 6 and (2) increases kidney Na, K-ATPase activity.
Subject(s)
Adaptation, Physiological , Animals, Newborn/physiology , Betamethasone/pharmacology , Glucocorticoids/pharmacology , Kidney/drug effects , Lung/drug effects , Animals , Betamethasone/administration & dosage , Blood Pressure/drug effects , Cardiovascular System/drug effects , Endocrine System/drug effects , Female , Fetal Organ Maturity , Glomerular Filtration Rate/drug effects , Glucocorticoids/administration & dosage , Male , Papio , Pregnancy , Prenatal Exposure Delayed Effects , Respiration, Artificial/veterinaryABSTRACT
OBJECTIVE: Renal and cardiovascular function improves in preterm newborn lambs after a single prenatal betamethasone treatment. We hypothesized that multiple betamethasone exposures would further improve renal and cardiovascular adaptation. STUDY DESIGN: Pregnant ewes were chosen randomly to receive saline solution, one dose of 0.5 mg/kg betamethasone at 104 days of gestation, or three doses of 0.5 mg/kg betamethasone at 104, 111, and 118 days of gestation. Lambs were delivered at 125 days of gestation (preterm) or 145 days of gestation (term). Renal and cardiovascular responses to phenylephrine were evaluated at 2 hours of age. RESULTS: The preterm single and multiple betamethasone-treated lambs comparably increased glomerular filtration rate, urinary flow and osmolar clearance, and sodium excretion in response to phenylephrine. Term responses were similar and not influenced by betamethasone exposure. CONCLUSION: Multiple courses of betamethasone do not further improve renal and cardiovascular responses from a single betamethasone dose. Renal and cardiovascular function at term is not affected by early prenatal betamethasone exposure.