HOME HELP FEEDBACK SUBSCRIPTIONS ARCHIVE SEARCH TABLE OF CONTENTS		QUICK SEARCH:   [advanced] Author: Keyword(s): Year:  Vol:  Page:

This Article Full Text Full Text (PDF) All Versions of this Article: 285/3/R664    most recent 00195.2003v1 Alert me when this article is cited Alert me if a correction is posted Citation Map Services Email this article to a friend Similar articles in this journal Similar articles in ISI Web of Science Similar articles in PubMed Alert me to new issues of the journal Download to citation manager Citing Articles Citing Articles via HighWire Citing Articles via ISI Web of Science (20) Citing Articles via Google Scholar Google Scholar Articles by Keenan, D. M. Articles by Veldhuis, J. D. Search for Related Content PubMed PubMed Citation Articles by Keenan, D. M. Articles by Veldhuis, J. D.

COMPLEX FUNCTION OF THE CENTRAL NERVOUS SYSTEM, SLEEP AND LOCOMOTION

Physiological control of pituitary hormone secretory-burst mass, frequency, and waveform: a statistical formulation and analysis

¹Department of Statistics, University of Virginia, Charlottesville, Virginia 22904; ²Department of Internal Medicine, Leiden University, Rapenburg 70, NA-2300 RA Leiden, The Netherlands; and ³Division of Endocrinology and Metabolism, Department of Internal Medicine, Mayo Medical School and Graduate School of Medicine, General Clinical Research Center, Mayo Clinic, Rochester, Minnesota 55905

Submitted 11 April 2003 ; accepted in final form 5 May 2003

The present study investigates the time-varying control of pituitary hormone secretion over the day and night (D/N). To this end, we implemented an analytical platform designed to reconstruct simultaneously 1) basal (nonpulsatile) secretion, 2) single or dual secretory-burst waveforms, 3) random effects on burst amplitude, 4) stochastic pulse-renewal properties, 5) biexponential elimination kinetics, and 6) experimental uncertainty. The statistical solution is conditioned on a priori pulse-onset times, which are estimated in the first stage. Primary data composed of thyrotropin (TSH) concentrations were monitored over 24 h in 27 healthy adults. According to statistical criteria, 21/27 profiles favored a dual compared with single secretory-burst waveform. An objectively defined waveform change point (D/N boundary) emerged at 2046 (±23 min), after which 1) the mass of TSH released per burst increases by 2.1-fold (P < 0.001), 2) TSH secretory-burst frequency rises by 1.2-fold (P < 0.001), 3) the latency to maximal TSH secretion within a burst decreases by 67% (P < 0.001), 4) variability in secretory-burst shape diminishes by 50% (P < 0.001), and 5) basal TSH secretion declines by 17% (P < 0.002). In contrast, the regularity of successive burst times and the slow-phase half-life are stable. In conclusion, nycthemeral mechanisms govern TSH secretory-burst mass, frequency, waveform, and variability but not evidently TSH elimination kinetics or the pulse-timing process. Further studies will be required to assess the generality of the foregoing distinctive control mechanisms in other hypothalamo-pituitary axes.

secretion; thyrotrope; hypothalamus; pulsatility

This article has been cited by other articles:

				J. D. Veldhuis, D. M. Keenan, and C. Y. Bowers Peripheral estrogen receptor-{alpha} selectively modulates the waveform of GH secretory bursts in healthy women Am J Physiol Regulatory Integrative Comp Physiol, October 1, 2007; 293(4): R1514 - R1521. [Abstract] [Full Text] [PDF]

				J. D. Veldhuis, D. M. Keenan, and C. Y. Bowers Estimation of the size and shape of GH secretory bursts in healthy women using a physiological estradiol clamp and variable-waveform deconvolution model Am J Physiol Regulatory Integrative Comp Physiol, September 1, 2007; 293(3): R1013 - R1021. [Abstract] [Full Text] [PDF]

				D. M. Keenan, F. Roelfsema, and J. D. Veldhuis Endogenous ACTH concentration-dependent drive of pulsatile cortisol secretion in the human Am J Physiol Endocrinol Metab, October 1, 2004; 287(4): E652 - E661. [Abstract] [Full Text] [PDF]