title: The effect of follicular fluid on intracellular free calcium levels in human spermatozoa.
abstract: In this study, we demonstrate the effect of follicular fluid (FF) on free cytosolic calcium ion ([Ca2+]i) in human spermatozoa, using a fluorescent indicator "fura 2," and we evaluate the factors that increase [Ca2+]i in FF. A significant and immediate [Ca2+]i increase (656.3 +/- 148.6 nM) was elicited by intact FF. The increase in [Ca2+]i elicited by lipid-stripped FF was only 50% (322 +/- 68.7 nM) of that elicited by intact FF. However, 82% of the [Ca2+]i increase elicited by intact FF was observed when lipid-stripped FF was supplemented with progesterone, but not when it was supplemented with estradiol. Also, progesterone at the concentrations of 1 ng/ml to 1 microgram/ml caused a significant increase in [Ca2+]i by itself, but estradiol produced a small effect, ranging from 3% to 9% of the effect produced by progesterone. These results indicate that progesterone plays a major role in the lipid fraction in FF to elicit the entry of calcium into human spermatozoa.
authors.affiliation: Department of Obstetrics and Gynecology, Ehime University, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Fukui
authors.forename: Y
authors.initials: Y
authors.lastname: Takeda
authors.forename: J
authors.initials: J
authors.lastname: Yano
authors.forename: R
authors.initials: R
authors.lastname: Kaura
authors.forename: H
authors.initials: H
authors.lastname: Kitagawa
authors.forename: H
authors.initials: H
authors.lastname: Suginami
authors.forename: S
authors.initials: S
authors.lastname: Matsuura
authors.forename: K
authors.initials: K
authors.lastname: Oka
mesh_terms: D002118:Calcium / Q000032:analysis*; D004958:Estradiol / Q000032:analysis; D005260:Female; D015571:Follicular Fluid / Q000502:physiology*; D006801:Humans; D008297:Male; D011374:Progesterone / Q000032:analysis; D013094:Spermatozoa / Q000737:chemistry*
chemical_list: D011374:Progesterone; D004958:Estradiol; D002118:Calcium