title: Differential effects of light/dark recombinant human prolactin administration on the submaxillary lymph nodes and spleen activity of adult male mice.
abstract: OBJECTIVE
  Day/night variations in cellularity, percentage of CD4+, CD8+ and double-positive (CD4+-CD8+) lymphocytes, lipopolysaccharide (LPS)- and concanavalin A (Con A)-induced lymphocyte proliferation and natural killer (NK) activity, and the effect of timed administration of recombinant human prolactin (h-PRL) on the above-mentioned parameters were investigated in the submaxillary lymph nodes and spleen of adult male mice.
  
  
  RESULTS
  In controls, the percentage of CD4+, double-positive lymphocytes, LPS- or Con A-induced blastogenic proliferation and NK activity in the spleen differ during the dark phase as compared to the light phase. When administered during the dark period, h-PRL induced immunosuppresion in the percentage of CD4+, double-positive (CD4+-CD8+) lymphocytes. Con A- and LPS-induced lymphocyte proliferation and NK activity as compared to untreated controls. When h-PRL was administered during the light period, the cellularity increased, and h-PRL was immunosuppressive in Con A- and LPS-induced lymphcoyte proliferation and NK activity as compared to controls. Moreover, in control submaxillary lymph nodes the cellularity, percentage of CD8+, double-positive lymphocytes, blastogenic proliferation in the presence of Con A and LPS and NK activity differ when comparing the dark with the light phase. When administered during the dark period h-PRL induced immunosuppression in the percentage of double-positive (CD4+-CD8+) lymphocytes, Con A- and LPS-induced lymphocyte proliferation as compared to controls. When h-PRL is administered during the light period, no effects were observed.
  
  
  CONCLUSIONS
  These results indicate the existence of differential day/night variations in the cellular immune response depending upon the lymphoid organ considered. Because of the administration of h-PRL a differential modulation of this circadian variation was also observed.
authors.affiliation: Departamento de Bioquímica y Biología Molecular III, Facultad de Medicina Universidad Complutense, Madrid, España. pelayos@med.ucm.es
authors.forename: A I
authors.initials: AI
authors.lastname: Esquifino
authors.forename: A
authors.initials: A
authors.lastname: Arce
authors.forename: M P
authors.initials: MP
authors.lastname: Alvarez
authors.forename: F
authors.initials: F
authors.lastname: Chacon
authors.forename: H
authors.initials: H
authors.lastname: Brown-Borg
authors.forename: A
authors.initials: A
authors.lastname: Bartke
mesh_terms: D000818:Animals; D015496:CD4-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D018414:CD8-Positive T-Lymphocytes / Q000187:drug effects / Q000276:immunology; D002455:Cell Division / Q000187:drug effects / Q000276:immunology; D002940:Circadian Rhythm / Q000276:immunology*; D003208:Concanavalin A / Q000494:pharmacology; D003624:Darkness; D004305:Dose-Response Relationship, Drug; D004334:Drug Administration Schedule; D006801:Humans; D007111:Immunity, Cellular / Q000187:drug effects / Q000276:immunology*; D007694:Killer Cells, Natural / Q000187:drug effects / Q000276:immunology; D008027:Light; D008070:Lipopolysaccharides / Q000494:pharmacology; D008198:Lymph Nodes / Q000187:drug effects / Q000276:immunology*; D008213:Lymphocyte Activation / Q000187:drug effects / Q000276:immunology*; D008297:Male; D051379:Mice; D015213:Neuroimmunomodulation / Q000187:drug effects / Q000276:immunology; D011388:Prolactin / Q000276:immunology / Q000494:pharmacology*; D011994:Recombinant Proteins / Q000276:immunology / Q000494:pharmacology; D013154:Spleen / Q000187:drug effects / Q000276:immunology*
chemical_list: D008070:Lipopolysaccharides; D011994:Recombinant Proteins; D003208:Concanavalin A; D011388:Prolactin