title: Circadian and circannual rhythms in plasma hormones and other variables of five healthy young human males.
abstract: Every other month (plasma) and every month (urine) circadian rhythms were documented during the course of 14 months. Annual changes were validated in the 24 h mean of: plasma FSH (annual crest time: February), LH (March), thyroxine (September), cortisol (February), renin activity (April), testosterone (October), urinary 17-hydroxycorticosteroids (March), aldosterone (March), potassium (May) as well as sexual activity (September) [self-recorded daily]. Plasma prolactin did not show an annual variation. In addition, annual changes in the circadian acrophase (crest time location in the 24 h scale) occurred for some of the documented variables: plasma thyroxine, cortisol, renin activity, testosterone, urinary aldosterone and potassium.
mesh_terms: D015065:17-Hydroxycorticosteroids / Q000652:urine; D000328:Adult; D000450:Aldosterone / Q000652:urine; D002940:Circadian Rhythm; D005640:Follicle Stimulating Hormone / Q000097:blood; D006728:Hormones / Q000097:blood*; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D011188:Potassium / Q000652:urine; D011388:Prolactin / Q000097:blood; D012083:Renin / Q000097:blood; D012621:Seasons; D012725:Sexual Behavior; D013739:Testosterone / Q000097:blood; D013974:Thyroxine / Q000097:blood
chemical_list: D015065:17-Hydroxycorticosteroids; D006728:Hormones; D013739:Testosterone; D000450:Aldosterone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D012083:Renin; D013974:Thyroxine; D011188:Potassium; D006854:Hydrocortisone