RESUMO
OBJECTIVE: To evaluate the duration and level of hypothalamic-pituitary-adrenal (HPA) axis suppression in premature infants treated with a prolonged course of glucocorticoids for chronic lung disease. STUDY DESIGN: We evaluated HPA axis function in nine very low birth weight (VLBW) infants before and 48 hours after a prolonged (14 to 42 days) dexamethasone (Dex) course. Seven of these infants underwent serial testing in the Clinical Research Center to evaluate the time course of HPA axis recovery. Adrenal function was assessed directly with synthetic adrenocorticotropic hormone (ACTH) stimulation, pituitary function with ovine corticotrophin releasing hormone (oCRH) stimulation, and combined axis function with 3-hour metyrapone testing. RESULTS: Baseline cortisol values were higher before Dex therapy (18.6 +/- 3.9 microg/dl; mean +/- SEM) than after (5.77 +/- 1.45 microg/dl; p < 0.01), as were ACTH-stimulated cortisol levels (24.8 +/- 1.7 microg/dl vs 12.0 +/- 2.2 microg/dl; p < 0.001). ACTH response to oCRH decreased after Dex treatment (22.8 +/- 7.6 pg/ml vs 11.5 +/- pg/ml), but this was not statistically significant (p = 0.18). 11-Deoxycortisol (11-DOC) response to metyrapone dropped from 11.1 +/- 0.5 microg/dl to 4.7 +/- 1.0 microg/dl after Dex therapy (p < 0.0001). Longitudinal testing reveals that adrenal suppression may be short-lived, while recovery of higher centers is more delayed. CONCLUSIONS: Basal cortisol levels may be used as a screening test, but if the level is less than 15 microg/dl, more definitive testing should be performed. The sluggish recovery of higher HPA axis centers is most reliably evaluated by using 11-DOC response to a single dose of metyrapone in VLBW infants after prolonged Dex therapy.
Assuntos
Anti-Inflamatórios/efeitos adversos , Dexametasona/efeitos adversos , Sistema Hipotálamo-Hipofisário/efeitos dos fármacos , Sistema Hipófise-Suprarrenal/efeitos dos fármacos , Hormônio Adrenocorticotrópico , Doença Crônica , Hormônio Liberador da Corticotropina , Idade Gestacional , Humanos , Hidrocortisona/sangue , Recém-Nascido de muito Baixo Peso , Estudos Longitudinais , Pneumopatias/diagnóstico , Pneumopatias/tratamento farmacológico , Metirapona , Radioimunoensaio , Fatores de TempoRESUMO
Studies were performed to investigate vitamin D metabolism in Mexican-Americans. Groups of 15 whites and 16 Mexican-Americans ranging in age from 18 to 41 years were evaluated. All of them were within 25% of their ideal body weight. Each of them was admitted to the Clinical Research Center of the University of Texas Health Science Center and placed on a daily diet estimated to contain 400 mg calcium and 900 mg phosphate. It was found that whereas serum vitamin D (1.8 +/- 0.5 versus 7.6 +/- 1.3 ng/ml, P less than 0.001) and serum 25-hydroxyvitamin D (9 +/- 1 versus 17 +/- 2 ng/ml, P less than 0.01) were significantly lower and serum 1,25-dihydroxyvitamin D (37 +/- 2 versus 28 +/- 2 pg/ml, P less than 0.001) was significantly higher in the Mexican-Americans than in the whites, serum calcium (9.1 +/- 0.1 versus 9.2 +/- 0.1 mg/dl), magnesium (1.84 +/- 0.07 versus 1.80 +/- 0.07 mEq/liter), and Gla protein (19 +/- 3 versus 21 +/- 2 ng/ml) were not different in the two groups. Urinary calcium (144 +/- 14 versus 124 +/- 16 mg/day), phosphate (672 +/- 51 versus 683 +/- 44 mg/day), sodium (110 +/- 8 versus 99 +/- 9 mEq/day), potassium (43 +/- 4 versus 49 +/- 3 mEq/day), and magnesium (7.3 +/- 0.7 versus 7.7 +/- 0.5 mEq/day) and creatinine clearance (173 +/- 14 versus 154 +/- 7 liters/day) were not different in the two groups.(ABSTRACT TRUNCATED AT 250 WORDS)