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Similar Effects between Follicular and Luteal Phases on the Urinary Levels of 6‐sulfatoxymelatonin following Endurance Exercise
Author(s) -
Yasuda Nobuo,
Tanioka Toshihiro
Publication year - 2016
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.30.1_supplement.1288.8
Subject(s) - luteal phase , medicine , follicular phase , urinary system , endocrinology , menstrual cycle , urine , physiology , hormone
The major urinary melatonin catabolite is 6‐sulfatoxymelatonin, which has been demonstrated as a good marker of pineal function. Although previous studies have shown exercise‐induced changes in melatonin metabolism, it still remains inconclusive whether prolonged exercise during two different menstrual cycle phases influences urinary 6‐sulfatoxymelatonin secretion. The purpose of the study was to determine the effects of the follicular and luteal phases on the urinary levels of 6‐sulfatoxymelatonin after 2‐h endurance exercise in women. Eleven recreationally active premenopausal women served as the participants (peak oxygen uptake (VO 2 peak): 46.1±5.0 mL/kg/min [mean±SD]). During the follicular (F: 5~8 days after the onset of the menses) and luteal (L: 22~25 days after the onset of the menses) phases, all participants carried out the same submaximal exercise protocol (2‐h cycling exercise at 60%VO 2 peak). Carbohydrate‐electrolyte solution was consumed every twenty minutes (2 ml/kg body mass) during each exercise protocol in order to delay fatigue and prevent hypoglycemia and dehydration. Before (Pre) and after (immediately Post) each exercise, spot urine samples were collected for later analysis of the urinary levels of 6‐sulfatoxymelatonin quantified by enzyme‐linked immunosorbent assay. Regarding the urinary levels of 6‐sulfatoxymelatonin (ng/mg creatinine), two‐way (phase × time) analysis of variances demonstrated a significant main effect for time (p<0.05), but not for phase or interaction (Pre=21.1±3.5, Post=33.0±8.5 for F; Pre=16.3±5.4, Post=33.5±9.5 for L). These findings indicate that acute moderate cycling exercise appears to be similar at the urinary levels of 6‐sulfatoxymelatonin during two different menstrual phases. Support or Funding Information Supported partly by funds from the Grant‐in‐Aid for Scientific Research (C) (Grant No.23500867).