@entity1 often exhibit larger hormonal and subjective responses to opioid receptor antagonists than @entity1 , but the biological mechanisms mediating this effect remain unclear. Among @entity1 , fluctuations in @entity53 (E2) and @entity1420 (P4) across the menstrual cycle (MC) affect the endogenous opioid system. Therefore, the goal of the current study was to compare acute @entity836 response between @entity1 in the early follicular phase of the MC (low @entity36491 ), @entity1 in the luteal phase of the MC (high @entity36491 ), and @entity1 . Seventy healthy controls (n=46 @entity1 ) participated in two morning sessions in which they received 50mg @entity836 or placebo in a randomized, counterbalanced order. @entity1 were randomized to complete both sessions in either the early follicular (n=23) or luteal phase of the MC. Serum @entity701 , salivary @entity701 , prolactin, luteinizing hormone (LH), and subjective response were assessed upon arrival to the laboratory and at regular intervals after pill administration. In luteal and early follicular @entity1 but not @entity1 , @entity836 (vs. placebo) increased serum @entity701 and prolactin levels from baseline; however, the @entity836 -induced increases in these hormones were significantly greater in luteal @entity1 than early follicular @entity1 . Additionally, only luteal @entity1 demonstrated an increase from baseline in salivary @entity701 levels and the severity of adverse drug effects in response to @entity836 . In sum, the results indicate that luteal phase @entity1 are more sensitive to acute hormonal and subjective effects of @entity836 than early follicular @entity1 and @entity1 . These findings may have important implications for the use of @entity836 in @entity1 .

Sex differences in acute hormonal and subjective response to XXXX : The impact of menstrual cycle phase.

@entity1 :: ('9606', 'Species') :: ['men', 'women', 'Women'] @entity836 :: ('MESH:D009271', 'Chemical') :: ['naltrexone'] @entity36491 :: ('6044;201780', 'Gene') :: ['E2 and P4'] @entity1420 :: ('MESH:D011374', 'Chemical') :: ['progesterone'] @entity53 :: ('MESH:D004958', 'Chemical') :: ['estradiol'] @entity701 :: ('MESH:D006854', 'Chemical') :: ['cortisol']
@entity836 :: (MESH:D009271,Chemical) :: ['naltrexone']
