Many endocrine systems are subject to seasonal variation. However, studies of the @entity2339 in @entity1 have been limited to @entity1 with @entity146 with conflicting results. We studied 105 healthy @entity1 , age 24-33 yr, during a 15-month period that included two winters. We measured @entity701 and its metabolites by gas chromatography/mass spectrometry in plasma and urine and the intensity of dermal blanching after overnight topical application of @entity2715 . There were no differences between subjects studied during the two winter periods, but marked differences between subjects studied in winter and summer. In winter, 0900-h plasma @entity701 concentrations were higher (73 +/- 10 ng/mL, n = 41 vs. 35 +/- 4, n = 25 in summer; P < 0.01), total @entity701 metabolite excretion was lower (678 +/- 67 micrograms/mmol @entity1011 vs. 900 +/- 98; P < 0.05), the ratio of metabolites of @entity701 to those of @entity821 was higher (3.0 +/- 0.2 vs. 2.1 +/- 0.1; P < 0.01), and dermal glucocorticoid sensitivity was higher (7.2 +/- 0.4 arbitrary units vs. 5.6 +/- 0.5; P < 0.02). Although blood pressure and fasting @entity2690 / @entity413 relationships were not measurably different between seasons, these correlated with dermal vasoconstriction and @entity701 metabolite excretion rate. We conclude that plasma @entity701 and tissue sensitivity to glucocorticoids are higher in winter, but @entity701 production rate is reduced. This could be explained by a reduction in @entity701 clearance rate: urinary free @entity701 / @entity821 ratios were not different but A-ring-reduced metabolites of @entity701 were higher in winter, suggesting that conversion of @entity821 to @entity701 by hepatic 11 beta-hydroxysteroid dehydrogenase 1 is enhanced. It is an intriguing possibility that increased glucocorticoid activity contributes to the increased prevalence of disease during the winter.

Seasonal variation in glucocorticoid activity in healthy XXXX .

@entity1 :: ('9606', 'Species') :: ['patients', 'man', 'men'] @entity821 :: ('MESH:D003348', 'Chemical') :: ['cortisone'] @entity2715 :: ('MESH:D001507', 'Chemical') :: ['beclomethasone dipropionate'] @entity146 :: ('MESH:D001523', 'Disease') :: ['psychiatric illness'] @entity2690 :: ('3630', 'Gene') :: ['insulin'] @entity2339 :: ('MESH:D007029', 'Disease') :: ['hypothalamic-pituitary-adrenal axis'] @entity701 :: ('MESH:D006854', 'Chemical') :: ['cortisol'] @entity1011 :: ('MESH:D003404', 'Chemical') :: ['creatinine'] @entity413 :: ('MESH:D005947', 'Chemical') :: ['glucose']
@entity1 :: (9606,Species) :: ['men']
