title: [Annual variations in plasma testosterone levels in prepuberal subjects].
abstract: 40 prepubertal boys, aged 6 to 10 years, were studied from 1977 to 1979 in order to evidence any circannual rhythm in the testosterone plasmatic levels. The patients observed in the following life schedule: nocturnal rest from 2200 to 0600 circa, meals at 0800, 1300, 1900. Plasma samples were taken at 0800 and testosterone was assayed by RIA. Testosterone data were fitted a cosine function, by least square method in order to describe any rhythm and to estimate its parameters:mesor, amplitude, acrophase. A significative circannual rhythm in the testosterone levels is present (P= 0.008) with Acrophase in July (-198.38 degrees +/- 18.26 ES). Our study suggests that a significative testosterone rhythm, with circannual periodicity, is present also in prepubertal age.
mesh_terms: D002648:Child; D006801:Humans; D008297:Male; D010507:Periodicity; D011627:Puberty; D012621:Seasons; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone
vernacular_title: Variazioni circannuali dei livelli di testosterone plasmatico in soggetti prepuberi.