Ea. Lynch et al., GENDER DIFFERENCES IN IL-1-ALPHA, IL-1-BETA, AND IL-1 RECEPTOR ANTAGONIST SECRETION FROM MONONUCLEAR-CELLS AND URINARY-EXCRETION, The Journal of immunology, 153(1), 1994, pp. 300-306
Previous studies have reported increased secretion of IL-1-like activi
ty from mononuclear cells and increased circulating levels during the
luteal phase of the menstrual cycle. In this investigation, specific R
IAs for the agonists IL-1 alpha and IL-beta as well as IL-1 receptor a
ntagonist (IL-1Ra) were used to determine whether differential IL-1 se
cretory patterns exist between men and women or between phases of the
menstrual cycle. Mononuclear cells were isolated from six men and five
women at 4-h intervals from 8 am to 8 pm, with the women studied once
in midfollicular phase and once in midluteal phase. In the absence of
any intentional stimulation, significant differences in secretion wer
e observed between groups (p < 0.03) for all three species of IL-1: wo
men's cells isolated during the luteal phase secreted 5- to 10-fold mo
re than cells from men, and women's cells isolated during the follicul
ar phase secreted 13- to 28-fold more than cells from men. In addition
, total 24-h urine samples were collected in intervals with end points
coinciding with the blood samples. Urinary excretion correlated with
cellular secretion for IL-beta and IL-1Ra (p = 0.024 and 0.028, respec
tively), indicating that the in vitro results may correspond to differ
ential processes occurring in vivo. Although greater absolute amounts
of each species of IL-1 were secreted during the follicular phase, the
ratio of agonist to antagonist secreted was greater in the luteal pha
se (p < 0.05), in agreement with previous studies of bioactivity. Thes
e results indicate that the regulation of IL-1 secretion is fundamenta
lly different in women compared with men and alludes to the possibilit
y that IL-1 may serve different biologic functions in women than men.