title: Diurnal ACTH and plasma cortisol variations in healthy dogs and in those with pituitary-dependent Cushing's syndrome before and after treatment with retinoic acid.
abstract: Daytime variations in ACTH and plasma cortisol were studied in healthy dogs and in dogs with pituitary-dependent hypercortisolism (PDH), before and after treatment with retinoic acid. In control dogs ACTH showed a higher concentration at 8.00 AM and between 2.00 and 6.00 PM, with the lowest concentration registered at 10.00 AM (p<0.05 vs. 8.00 AM and 2.00 PM and p<0.01 vs. 4.00 PM). Cortisol did not show significant differences. In dogs with PDH, ACTH was lower at 8.00 AM (ACTH: p<0.01 vs. 2.00 and 4.00 PM; and p<0.05 vs. 6.00 PM). The lowest cortisol concentration was registered at 8.00 AM and 8.00 PM and the highest at 4.00 PM (p<0.05 vs. 8.00 AM and p<0.01 vs. 8.00 PM). After treatment, the lowest ACTH concentration was registered at 10.00 AM (p<0.01 vs. 2.00 and 4.00 PM). To conclude, the adrenal is desensitized in PDH possibly showing negative in diagnostic tests.
authors.affiliation: A. Clínica Médica de Pequeños Animales, Hospital Escuela de Med Veterinaria, Unidad de Endocrinología, Chorroarín 280, 1424 Ciudad de Buenos Aires, Cap. Fed., Argentina. vcastill@fvet.uba.ar
authors.forename: V A
authors.initials: VA
authors.lastname: Castillo
authors.forename: M F
authors.initials: MF
authors.lastname: Cabrera Blatter
authors.forename: N V
authors.initials: NV
authors.lastname: Gómez
authors.forename: V
authors.initials: V
authors.lastname: Sinatra
authors.forename: M F
authors.initials: MF
authors.lastname: Gallelli
authors.forename: M C
authors.initials: MC
authors.lastname: Ghersevich
mesh_terms: D000324:Adrenocorticotropic Hormone / Q000097:blood*; D000818:Animals; D002940:Circadian Rhythm / Q000187:drug effects; D003480:Cushing Syndrome / Q000097:blood / Q000188:drug therapy / Q000662:veterinary*; D004283:Dog Diseases / Q000097:blood* / Q000188:drug therapy; D004285:Dogs / Q000097:blood*; D005260:Female; D006854:Hydrocortisone / Q000097:blood*; D008297:Male; D018709:Statistics, Nonparametric; D014212:Tretinoin / Q000627:therapeutic use*
chemical_list: D014212:Tretinoin; D000324:Adrenocorticotropic Hormone; D006854:Hydrocortisone