NCT05279053

Mapping Brain Glutamate in Humans: Sex Differences in Cigarette Smokers

Completed Results posted Last updated 20 March 2026

What this trial tests

trial testing Abstinence and Smoking in Sex in 58 participants. Completed in 31 March 2023.

Timeline

1 April 2021

Primary endpoint
31 March 2023

31 March 2023

Quick facts

Lead sponsor	University of California, Los Angeles
Status	Completed
Study type	OBSERVATIONAL
Enrollment	58
Start date	1 April 2021
Primary completion	31 March 2023
Estimated completion	31 March 2023
Sites	1 location across United States

Drugs / interventions tested

• Abstinence and Smoking

Conditions studied

• Sex — all drugs for Sex →
• Cigarette Smoking — all drugs for Cigarette Smoking →

Sponsor

University of California, Los Angeles

Who can join

Adults 18 to 45, any sex, with Sex or Cigarette Smoking. Patients with the condition only — healthy volunteers not accepted.

Results — posted to ClinicalTrials.gov

Per-arm endpoint measurements with 95% confidence intervals where reported. Source: trial results section.

Glutamate in the Dorsal Anterior Cingulate Cortex Primary · Measured before and after smoking a cigarette by both groups (men and women). Group means below reflect overall group means averaged across time points as reported from descriptive statistics in the Generalized Linear Mixed Model.

Glutamate levels, as measured using MRS, in the dorsal anterior cingulate cortex.

Group	Value	95% CI
Male	8.11	± 1.71
Female	7.05	± 1.61

Glutamate in the Insula Primary · Measured before and after smoking a cigarette by both groups (men and women). Group means below reflect overall group means averaged across time points as reported from descriptive statistics in the Generalized Linear Mixed Model.

Glutamate levels, as measured using MRS, in the insula.

Group	Value	95% CI
Male	7.44	± 1.33
Female	6.98	± 1.36

Glutamate in Whole Brain (Gray Matter Plus White Matter). Primary · Measured before and after smoking a cigarette by both groups (men and women). Group means below reflect overall group means averaged across time points as reported from descriptive statistics in the Generalized Linear Mixed Model.

Glutamate measured using the MRS echoplanar spectroscopic imaging in abstinent smokers.

Group	Value	95% CI
Male	5.65	± 1.01
Female	5.53	± 1.02

Serum Estrogen Primary · Sampling performed on same day as MRS (before smoking).

Estrogen concentration measured in serum from blood samples drawn prior to MRS (women only).

Group	Value	95% CI
Female	92.77	± 65.16

Sponsor's own description

The proposed study evaluated sex differences in glutamate (Glu), with a focus on the dorsal anterior cingulate cortex (dACC), anterior insula, and thalamus, as well as how it is influenced by sex (males vs. females), smoking state (overnight abstinent vs. sated), and circulating ovarian hormones (estrogen and progesterone) in women. Glu was measured in the entire brain with special focus on the dorsal anterior cingulate cortex (dACC), anterior insula, and thalamus, all of which have been implicated in tobacco withdrawal, using an echo-planar spectroscopic imaging (EPSI) variant of magnetic resonance spectroscopy (MRS). Serum ovarian hormones (estrogen and progesterone) were measured for female participants to determine relationships between brain Glu and this hormone. Glu was be measured in smokers after overnight (\~12 h) abstinence and after participants smoked the first cigarette of the day.

Publications & conference data

No peer-reviewed publications indexed yet for this trial. Completed trials usually publish results within 12-18 months.