title: Diurnal variations and temporal coupling of bioactive and immunoactive luteinizing hormone, prolactin, testosterone and 17-beta-estradiol in adult men.
abstract: Diurnal variations and temporal coupling in the circulating levels of immunoactive and bioactive luteinizing hormone (LH) and prolactin (PRL), testosterone (T) and 17-beta-estradiol (E2) in plasma of 6 healthy men (mean age 33 years) were studied. Each hormonal profile was analyzed for circadian amplitude, acrophase and nadir. Acrophases for immunoactive LH and T were coincident and ranged between clock hours 1 and 5. Acrophase for bioactive LH ranged between 9 and 12 h and was coincident with nadir for T. Acrophase for E2 ranged between 15 and 18 h and was coincident with nadir for immunoactive LH (15-17 h). Acrophase for bioactive PRL and immunoactive PRL ranged between 20-23 and 23-4 h, respectively. The circadian amplitude for T showed a negative correlation coefficient with circadian amplitude of bioactive LH (alpha = -0.86) and positive correlation coefficient with circadian amplitude of immunoactive LH (alpha = 0.94). It is inferred that immunoactive LH may be a sensor of T concentration while bioactive LH may be actually involved in the feedback regulation of T secretion. It is suggested that PRL may have a key role in the regulation of LH secretion.
authors.affiliation: Institute for Research in Reproduction (ICMR), Parel, Bombay, India.
authors.forename: H S
authors.initials: HS
authors.lastname: Juneja
authors.forename: S
authors.initials: S
authors.lastname: Karanth
authors.forename: A
authors.initials: A
authors.lastname: Dutt
authors.forename: P
authors.initials: P
authors.lastname: Parte
authors.forename: P
authors.initials: P
authors.lastname: Meherjee
mesh_terms: D000328:Adult; D001681:Biological Assay; D002940:Circadian Rhythm; D004958:Estradiol / Q000097:blood*; D006801:Humans; D007986:Luteinizing Hormone / Q000097:blood*; D008297:Male; D011388:Prolactin / Q000097:blood*; D011863:Radioimmunoassay; D012016:Reference Values; D012044:Regression Analysis; D013739:Testosterone / Q000097:blood*
chemical_list: D013739:Testosterone; D004958:Estradiol; D011388:Prolactin; D007986:Luteinizing Hormone