title: Daily rhythmic and non-rhythmic variations of follitropin, lutropin, testosterone, and sex-hormone-binding globulin in men.
abstract: The circadian rhythmic variations of the serum concentrations of follitropin, lutropin, sex-hormone-binding globulin and testosterone, the ratio between the serum concentrations of testosterone and sex-hormone-binding globulin, and the salivary concentration of testosterone were investigated in a group of 13 apparently healthy men. Venous blood and salivary specimens were collected at 4-h intervals over a 24-h period. The circadian rhythms were studied by using a periodic function resulting from the sum of two cosine functions with periods of 24 and 12 h. The serum concentrations of follitropin and lutropin showed no significant rhythmic variations. For the salivary concentration of testosterone and for the ratio between the serum concentrations of testosterone and sex-hormone-binding globulin, only the cosine function with a period of 24 h was significant. Serum concentrations of sex-hormone binding globulin and testosterone were significantly affected by 24- and 12-h rhythmic components. Of the quantities studied, the salivary concentration of testosterone showed the greatest daily rhythmic variation (28.8% of the mean estimated over rhythm).
authors.affiliation: Servei de Bioquímica Clínica, Ciutat Sanitària i Universitària de Bellvitge, L'Hospitalet de Llobregat, Barcelona, Spain.
authors.forename: J
authors.initials: J
authors.lastname: Valero-Politi
authors.forename: X
authors.initials: X
authors.lastname: Fuentes-Arderiu
mesh_terms: D000328:Adult; D002940:Circadian Rhythm; D005640:Follicle Stimulating Hormone / Q000502:physiology*; D006801:Humans; D007986:Luteinizing Hormone / Q000502:physiology*; D008297:Male; D012016:Reference Values; D012463:Saliva / Q000737:chemistry; D012738:Sex Hormone-Binding Globulin / Q000502:physiology*; D013739:Testosterone / Q000502:physiology*
chemical_list: D012738:Sex Hormone-Binding Globulin; D013739:Testosterone; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone