title: Diurnal variation in blood 17-hydroxyprogesterone concentrations in untreated congenital adrenal hyperplasia.
abstract: Blood spot 17-hydroxyprogesterone concentrations were measured serially over 24 hours in patients with congenital adrenal hyperplasia due to 21-hydroxylase deficiency before they started treatment with glucocorticoids, and the development of diurnal rhythm in pituitary-adrenal activity was studied. Five infants aged 2 to 26 days showed an intradiem variation of 17-hydroxyprogesterone concentrations within the diagnostic range but without a characteristic diurnal pattern. Blood spot 17-hydroxyprogesterone values in a further eight patients aged 3 months to 6.5 years showed a diurnal rhythm, with high concentrations in the morning and a nadir in the evening. The results suggest that a diurnal rhythm in pituitary-adrenal activity may develop as early as the third month of life in those infants with an increased endogenous concentration of adrenocorticotrophic hormone.
mesh_terms: D019326:17-alpha-Hydroxyprogesterone; D000312:Adrenal Hyperplasia, Congenital / Q000097:blood* / Q000503:physiopathology; D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm; D006801:Humans; D006908:Hydroxyprogesterones / Q000097:blood*; D007223:Infant; D007231:Infant, Newborn; D010913:Pituitary-Adrenal System / Q000503:physiopathology
chemical_list: D006908:Hydroxyprogesterones; D019326:17-alpha-Hydroxyprogesterone