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  • 1
    Electronic Resource
    Electronic Resource
    Circadian and ultradian variations of pituitary and pineal hormones in normal men: Evidence for a link between melatonin, gonadotropin, and prolactin secretion (1995)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 18 (1995), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The study was performed to investigate the physiological relationship between the pineal hormone melatonin and pituitary functions in normal men. Se-ries of blood samples were obtained at 10-min intervals for 24-hr periods from 10 male volunteers (age 19–25 years). Samplings were repeated after 2 weeks and 3 months. Serum levels of melatonin, follicle-stimulating hormone (FSH), luteiniz-ing hormone (LH), prolactin (PRL), and testosterone (T) were estimated by immu-noassay methods (LH, PRL, every sample; melatonin, every 30 min; T, every 4 hrs; FSH once for each session). Diurnal characteristics of PRL and melatonin profiles were estimated by complex cosinor analysis, while short-term pulsatility of LH and PRL secretion was analyzed by the PULSAR algorithm. Data were cor-related by linear regression analysis. The combined information of all three sam-pling sessions revealed significant negative correlations between the following parameters (N = 10): Amplitude (Ampl) melatonin and Ampl PRL: r = -0.727, P 〈 0.02; Ampl melatonin and maximal (Max) PRL values: r = -0.73, P 〈 0.02; Max melatonin and Max PRL: r = -0.725, P 〈 0.02; area under the curve (AUC) melatonin and Ampl PRL: r = -0.637, P 〈 0.05; AUC melatonin and Max PRL: r = -0.640; P 〈 0.05; duration (Dur) of melatonin synthesis and Ampl PRL: r = -0.685, P 〈 0.03; Dur melatonin and Max PRL: r = -0.676, P 〈 0.04; Dur mela-tonin and FSH levels: r = -0.663, P 〈 0. 04; AUC melatonin and LH mean con-centration: r = -0.732, P 〈 0. 02; Max melatonin and LH mean concentration: r = -0.657, P 〈 0.04. These correlations varied considerably between the three ses-sions, mainly due to intra-individual variabilities of secretory patterns of PRL and LH, while the melatonin profiles were comparably stable. The results indicate that melatonin production and pituitary functions may be related in normal men. Be-cause of the substantial intra- and inter-individual variations in hormone secretory patterns, large numbers of volunteers and/or repeated measurements are essential for studies addressing the pineal-pituitary connection in normal humans.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-079X.1995.tb00138.x
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  • 2
    Electronic Resource
    Electronic Resource
    Reliable analysis of individual human megaton profiles by complex cosinor analysis (1994)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of pineal research 16 (1994), S. 0 
    Details
    ISSN: 1600-079X
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Lerchl A, Partsch C-J. Reliable analysis of individual human melatonin profiles by complex cosinor analysis. J. Pineal Res. 1994: 16: 85–90.〈section xml:id="abs1-1"〉〈title type="main"〉AbstractThe analysis of diurnal secretion patterns of the pineal hormone melatonin should provide information about magnitude of peak concentration, time of peak (acrophase), and duration of elevated hormone levels. We report here on a method for analysis of human melatonin secretary rhythms which fulfills these requirements with considerable precision. Blood samples were obtained from 10 healthy male volunteers at 30 min intervals throughout a 24 hr period, three times (the initial blood sampling was repeated after 2 weeks and 3 months). These sets of 48 plasma samples per volunteer were analyzed for melatonin by radio immunoassay. The mean intra-assay variation was 10. 3%, and inter-assay variations were 15. 8% at 21 pg/ml, 11% at 28 pg/ml, and 9. 4% at 48. 6 pg/ml. Data were subjected to single cosinor analysis (SCA) or analyzed by a complex cosinor analysis (CCA) with the fundamental and the first harmonic as parameters. Both methods provided essentially the same information about the macrophages, whereas the CCA had a clear advantage in terms of better regression coefficients between the original data points and the calculated curve (CCA: r = 0.952 ± 0.018; SCA: r = 0.867 ± 0.039 [means ± SD]; P 〈 0.001). As a consequence, maximum and minimum values and the times of onset and cessation of melatonin production could be estimated easily and reliably without the need for rough and/or subjective measures. By comparing the three sampling sessions, the secretary rhythm of each individual was clearly reproducible (mean coefficient of variation 8. 4%), thus confirming earlier work. Interindividual differences, however, were quite pronounced, especially with respect to amplitudes (more than 25% coefficient of variation). The present method for describing the secretary pattern of emblazoning may also be useful for other study protocols since it requires only slightly more effort than the commonly used single cosinor analysis.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1600-079X.1994.tb00087.x
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    Paper (German National Licenses)
    Fulltext
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