Modulation of plasma melatonin concentrations by changes in posture.

Author(s): Nathan PJ, Jeyaseelan AS, Burrows GD, Norman TR

Publication: J Pineal Res, 1998, Vol. 24, Page 219-23

PubMed ID: 9572531 PubMed Review Paper? No

Purpose of Paper

Conclusion of Paper

Studies

1. Study Purpose

   The purpose of this study was to determine the effects of patient posture and time of specimen collection on nocturnal melatonin levels in plasma. The first specimens were drawn at 9:00 pm while volunteers were in the light. From this point on, volunteers were in a dark room (10-20 lux) until the end of the study period at 1:00 am. Volunteers were either seated for the entire duration, lying down for the entire duration, seated except for between 11:00 pm and 12:00 am when they rose to a standing position, or lying down except for between 11:00 pm and 12:00 am when they rose to a standing position. Plasma was frozen at -20 degrees C prior to analysis.

   Summary of Findings:

   Significantly higher levels of melatonin were measured in plasma collected while volunteers were sitting or standing as opposed to lying down (both p<0.05). But no significant differences in melatonin levels were observed between sitting and standing specimens. As expected, melatonin increased as time passed, but volunteer posture did not have a significant effect on the percentage of increase in melatonin levels between 11:00 pm and 12:00 am.

   Biospecimens

   • Bodily Fluid - Plasma
   • Bodily Fluid - Blood

   Preservative Types

   • Frozen

   Diagnoses:

   • Normal

   Platform:

   Analyte	Technology Platform
   Small molecule	Radioimmunoassay

   Pre-analytical Factors:

   Classification	Pre-analytical Factor	Value(s)
   Biospecimen Acquisition	Time of biospecimen collection	9:00 pm 10:00 pm 10:30 pm 11:00 pm 11:10 pm 11:20 pm 11:30 pm 11:40 pm 11:50 pm 12:00 am 12:10 am 12:20 am 12:30 am 12:40 am 12:50 am 1:00 am
   Biospecimen Acquisition	Patient posture	Sitting Standing Supine

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