title: The effects of estrogen and progesterone on blood glutamate levels: evidence from changes of blood glutamate levels during the menstrual cycle in women.
abstract: The gonadal steroids estrogen and progesterone have been shown to have neuroprotective properties against various neurodegenerative conditions. Excessive concentrations of glutamate have been found to exert neurotoxic properties. We hypothesize that estrogen and progesterone provide neuroprotection by the autoregulation of blood and brain glutamate levels. Venous blood samples (10 ml) were taken from 31 men and 45 women to determine blood glutamate, estrogen, progesterone, glucose, glutamate-pyruvate transaminase (GPT), and glutamate-oxaloacetate transaminase (GOT) levels, collected on Days 1, 7, 12, and 21 of the female participants' menstrual cycle. Blood glutamate concentrations were higher in men than in women at the start of menstruation (P < 0.05). Blood glutamate levels in women decreased significantly on Days 7 (P < 0.01), 12 (P < 0.001), and 21 (P < 0.001) in comparison with blood glutamate levels on Day 1. There was a significant decrease in blood glutamate levels on Days 12 (P < 0.001) and 21 (P < 0.001) in comparison with blood glutamate levels on Day 7. Furthermore, there was an increase in blood glutamate levels on Day 21 compared with Day 12 (P < 0.05). In women, there were elevated levels of estrogen on Days 7 (P < 0.05), 12, and 21 (P < 0.001), and elevated levels of progesterone on Days 12 and 21 (P < 0.001). There were no differences between men and women with respect to blood glucose concentrations. Concentrations of GOT (P < 0.05) and GPT (P < 0.001) were significantly higher in men than in women during the entire cycle. The results of this study demonstrate that blood glutamate levels are inversely correlated to levels of plasma estrogen and progesterone.
authors.affiliation: Department of Anesthesiology and Critical Care, Soroka Medical Center, Ben Gurion University, Beer Sheva, Israel. zlotnika@bgu.ac.il
authors.forename: Alexander
authors.initials: A
authors.lastname: Zlotnik
authors.forename: Benjamin F
authors.initials: BF
authors.lastname: Gruenbaum
authors.forename: Boaz
authors.initials: B
authors.lastname: Mohar
authors.forename: Ruslan
authors.initials: R
authors.lastname: Kuts
authors.forename: Shaun E
authors.initials: SE
authors.lastname: Gruenbaum
authors.forename: Sharon
authors.initials: S
authors.lastname: Ohayon
authors.forename: Matthew
authors.initials: M
authors.lastname: Boyko
authors.forename: Yael
authors.initials: Y
authors.lastname: Klin
authors.forename: Eyal
authors.initials: E
authors.lastname: Sheiner
authors.forename: Gad
authors.initials: G
authors.lastname: Shaked
authors.forename: Yoram
authors.initials: Y
authors.lastname: Shapira
authors.forename: Vivian I
authors.initials: VI
authors.lastname: Teichberg
mesh_terms: D000293:Adolescent; D000328:Adult; D001786:Blood Glucose / Q000032:analysis; D004967:Estrogens / Q000097:blood / Q000494:pharmacology*; D005260:Female; D018698:Glutamic Acid / Q000097:blood*; D006801:Humans; D008297:Male; D008597:Menstrual Cycle / Q000097:blood* / Q000187:drug effects; D008875:Middle Aged; D009994:Osmolar Concentration; D011374:Progesterone / Q000097:blood / Q000494:pharmacology*; D013997:Time Factors; D055815:Young Adult
chemical_list: D001786:Blood Glucose; D004967:Estrogens; D018698:Glutamic Acid; D011374:Progesterone