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PredicateObject
rdf:type
lifeskim:mentions
pubmed:issue
6
pubmed:dateCreated
1992-6-29
pubmed:abstractText
Osteocalcin (OC) in serum varies in a remarkably constant circadian rhythm with zenith at night and nadir in the morning. The factors controlling this rhythm are unknown, but several studies indicate that serum cortisol could be of major importance. We tested this hypothesis in a double-blind, placebo-controlled, cross-over study comprising 10 normal male volunteers (aged 23-31 yr) by measuring the response in serum OC and cortisol rhythms to a single dose of metyrapone (30 mg/kg body weight) administered at midnight. During placebo, serum cortisol consistently peaked early in the morning before 0730 h. Ingestion of metyrapone at 2400 h significantly postponed and flattened this peak (P less than 0.01). On both occasions, serum OC increased towards peak levels around 0300 h (P less than 0.01) with no overall differences in the OC profiles. However, when the serum OC time series were synchronized according to the individual cortisol nadirs, we found a significant (P less than 0.01) decrease in serum OC on the placebo day approximately 4 h after the cortisol nadir, whereas no significant changes (P greater than 0.50) were seen on the metyrapone day. Moreover, the mean serum OC level tended to be higher (P less than 0.10 in the interval 0-12 h, and P = 0.06 in the interval 4-8 h) on the metyrapone day compared with the placebo day. On the placebo day, the mean level of serum cortisol during the interval 0-4 h correlated inversely with the mean level of serum OC in the interval 4-8 h (r = 0.77, P less than 0.05). This relation was not found on the metyrapone day. In conclusion, administration of metyrapone, which reduced and postponed the early morning cortisol peak, abolished the normal morning decrease in serum OC. This strongly supports that changes in endogenous serum cortisol are of major importance for the circadian rhythm in serum OC.
pubmed:language
eng
pubmed:journal
pubmed:citationSubset
AIM
pubmed:chemical
pubmed:status
MEDLINE
pubmed:month
Jun
pubmed:issn
0021-972X
pubmed:author
pubmed:issnType
Print
pubmed:volume
74
pubmed:owner
NLM
pubmed:authorsComplete
Y
pubmed:pagination
1410-4
pubmed:dateRevised
2006-11-15
pubmed:meshHeading
pubmed:year
1992
pubmed:articleTitle
Inhibition of the morning cortisol peak abolishes the expected morning decrease in serum osteocalcin in normal males: evidence of a controlling effect of serum cortisol on the circadian rhythm in serum osteocalcin.
pubmed:affiliation
Aarhus Bone and Mineral Research group, University Department of Endocrinology and Metabolism, Aarhus Amtssygehus, Denmark.
pubmed:publicationType
Journal Article, Clinical Trial, Comparative Study, Controlled Clinical Trial, Research Support, Non-U.S. Gov't