title: Circadian rhythms in circulating T lymphocyte subtypes and plasma testosterone, total and free cortisol in five healthy men.
abstract: Circadian variations of circulating T lymphocyte subtypes and their possible relations with those of endogenous cortisol or testosterone were investigated in five healthy young men. Venous blood (40 ml) was obtained every 4 h for 24 h from each subject in January, March, June, August and November. Leucocyte and differential counts were measured. Mononuclear cells were isolated on Ficoll-Paque gradient, and samples were incubated with OKT3, OKT4 or OKT8 monoclonal antibodies for characterizing all T, T helper and T suppressor-cytotoxic lymphocytes respectively. The proportion of labelled lymphocytes was determined under an epifluorescence microscope and the counts of circulating lymphocyte subsets (cells/mm3) computed. Total and free cortisol and testosterone were also determined in the corresponding plasma samples. Results from analysis of variance and cosinor indicated statistically significant differences (P less than 0.001) as a function of both individual subject and circadian sampling time for all variables. Circadian rhythms (with a period, tau = 24 h) were validated for total, T and T helper lymphocytes and for the T helper: T suppressor-cytotoxic ratio (P less than 0.001), with double amplitudes (2A, total extent of variation accounted for by the fitted cosine function) ranging from 25% up to 50% of the 24 h mean (M), and acrophases (phi, time of maximum) localized near 0100 h. A rhythm with tau = 12 h characterized circulating T suppressor-cytotoxic lymphocytes (P less than 0.001; 2A = 36% of M; phi = 0830 and 2030 h). Circadian rhythms were also found for plasma cortisol (either total or free) and testosterone (P less than 0.001). No correlation was found however between time-qualified data of these hormones and the immunological variables herein investigated (162 pairs of data) whether or not a 4 h or an 8 h lag time was considered to allow for hormonal actions to operate. This suggests that neither the circadian organization of the adrenal cortex nor that of the testis play a prominent role in the circadian time structure of the circulation of T lymphocytes.
authors.affiliation: Institut de Cancérologie et d'Immunogénétique (CNRS UA04-1163), Villejuif, France.
authors.forename: F A
authors.initials: FA
authors.lastname: Lévi
authors.forename: C
authors.initials: C
authors.lastname: Canon
authors.forename: Y
authors.initials: Y
authors.lastname: Touitou
authors.forename: J
authors.initials: J
authors.lastname: Sulon
authors.forename: M
authors.initials: M
authors.lastname: Mechkouri
authors.forename: E D
authors.initials: ED
authors.lastname: Ponsart
authors.forename: J P
authors.initials: JP
authors.lastname: Touboul
authors.forename: J M
authors.initials: JM
authors.lastname: Vannetzel
authors.forename: I
authors.initials: I
authors.lastname: Mowzowicz
authors.forename: A
authors.initials: A
authors.lastname: Reinberg
mesh_terms: D000328:Adult; D000954:Antigens, Surface / Q000032:analysis; D002940:Circadian Rhythm; D006801:Humans; D006854:Hydrocortisone / Q000097:blood*; D007958:Leukocyte Count; D008297:Male; D013601:T-Lymphocytes / Q000145:classification* / Q000276:immunology; D013602:T-Lymphocytes, Cytotoxic; D006377:T-Lymphocytes, Helper-Inducer; D050378:T-Lymphocytes, Regulatory; D013739:Testosterone / Q000097:blood*
chemical_list: D000954:Antigens, Surface; D013739:Testosterone; D006854:Hydrocortisone