title: Circadian changes in salivary constituents and conductivity in women and men.
abstract: Circadian rhythms in salivary [glucose], [Na+], [K+] and conductivity were measured in 2 age groups of men (men A, 20-45 years and men B, 46-60 years) and 8 different states of fertility in women (normally menstruating, taking oral contraceptives, pregnant, lactational amenorrhea, lactational amenorrhea and taking oral contraceptives, lactating and menstruating, menopausal, and post-menopausal). Unstimulated whole saliva (2-3 ml) was collected every 3 h over a 48 h span. Analysis of Spearman Rank Correlations indicated significant circadian rhythms (significant positive coefficients) for all groups of [Na+] (mean = 0.577 +/- 0.040) and conductivity (mean = 0.410 +/- 0.050). There was no evidence of differences in prominence of rhythm across groups for [Na+] and conductivity. [K+] showed less evidence of rhythms and much greater variability between groups (mean correlation coefficient = 0.198 +/- 0.055). Rhythms in [glucose] (mean correlation coefficient = 0.409 +/- 0.051) were evident in all groups except men B (0.016), menopausal women (0.151) and post-menopausal women (0.310). Model analysis of the data showed no discernible rhythmic trend with age for either conductivity, [Na+] or [K+], where any differences were explainable by the group characteristics. The rhythm in [glucose] showed a significant weakening with age over all groups (F-ratio = 7.46**), and was different between men A and men B (F-ratio = 6.95**). It was concluded that circadian rhythms were present in whole unstimulated saliva for conductivity and [Na+] and that these rhythms were independent of reproductive state, whereas circadian rhythms in [K+] were dependent on reproductive state. Circadian rhythms for [glucose] were dependent on age. The loss of a rhythm in [glucose] with age indicates that glucose, Na+ and K+ are not linked in their entry into saliva. The influence of entry and reabsorption on the final concentrations of glucose, Na+ and K+ in saliva is discussed.
authors.affiliation: Department of Biochemistry, University of Western Australia, Nedlands.
authors.forename: C S
authors.initials: CS
authors.lastname: Atwood
authors.forename: I R
authors.initials: IR
authors.lastname: James
authors.forename: U
authors.initials: U
authors.lastname: Keil
authors.forename: N K
authors.initials: NK
authors.lastname: Roberts
authors.forename: P E
authors.initials: PE
authors.lastname: Hartmann
mesh_terms: D000328:Adult; D000375:Aging / Q000502:physiology; D002940:Circadian Rhythm / Q000502:physiology*; D004553:Electric Conductivity; D005260:Female; D005947:Glucose / Q000378:metabolism; D006801:Humans; D008297:Male; D008875:Middle Aged; D011188:Potassium / Q000378:metabolism; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology; D012463:Saliva / Q000378:metabolism*; D012964:Sodium / Q000378:metabolism
chemical_list: D012964:Sodium; D005947:Glucose; D011188:Potassium