title: Circadian and ultradian characteristics of plasma growth hormone in children with normal and short stature.
abstract: Circadian and ultradian variations characterize plasma growth hormone (GH) in 40 boys and 10 girls of short stature, and 15 boys and girls of normal stature, 6-14 yr of age, living on a diurnal waking (approximately 07:00 to approximately 22.00), nocturnal resting routine. Blood was drawn at about 3-h intervals during a 24-h span and serum stored frozen at -60 degrees C until radioimmunoassay for GH concentration. A linear least-squares spectrum analysis of those data reveals the anticipated statistically significant circadian rhythm as the principal spectral feature for all groups. Prominent components with a period of 12 h were also found for the groups of short boys and short girls, and of 8 h for short boys. A parameter comparison indicates similar circadian characteristics between short and normal children, whether one compares boys (p = .52, .30 and .84 for comparison of rhythm-adjusted means (M), amplituedes (A) and acrophases (phi), respectively), girls (p = .65, .37 and .92), or all children (p = .53, .31 and .87). These results notwithstanding, studies of GH responses to GH-releasing hormone in children with short stature and healthy controls should be extended to evaluate any possible difference in terms of gender and circadian or ultradian timing.
authors.affiliation: E.T.S.I. Telecomunicacion, Univ. de Santiago, Vigo, Spain.
authors.forename: R C
authors.initials: RC
authors.lastname: Hermida
authors.forename: L
authors.initials: L
authors.lastname: Garcia
authors.forename: C
authors.initials: C
authors.lastname: Lodeiro
authors.forename: D E
authors.initials: DE
authors.lastname: Ayala
authors.forename: T
authors.initials: T
authors.lastname: Iglesias
authors.forename: F
authors.initials: F
authors.lastname: Halberg
mesh_terms: D000293:Adolescent; D001827:Body Height / Q000187:drug effects / Q000502:physiology*; D002648:Child; D002940:Circadian Rhythm / Q000502:physiology*; D005260:Female; D006130:Growth Disorders / Q000188:drug therapy; D013006:Growth Hormone / Q000097:blood* / Q000502:physiology; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology / Q000627:therapeutic use; D006801:Humans; D008297:Male; D011863:Radioimmunoassay
chemical_list: D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone