Date of Award

1-1-2012

Document Type

Thesis

Degree Name

M.S.

Department

Biological Sciences

First Advisor

Nancy Lorenzon

Keywords

calcium, Estradiol, lactotropes, lactotrophs, MMQ

Abstract

Pituitary lactotrophs are excitable cells that exhibit spontaneous, calcium influx triggering prolactin (PRL) secretion to stimulate lactation. Lactotrophs express estrogen receptors (ER) and are a well established estrogen-responsive cell system. 17B-estradiol (E2) is known to directly affect lactotrophs by increasing PRL transcription and biosynthesis, intracellular Ca2+ concentration ([Ca2+]i) and PRL secretion. This study demonstrates that the MMQ clonal cell line, isolated from the 7315a rat pituitary tumor, is a model lactotroph cell line that is E2-responsive. Spontaneous and evoked Ca2+ transients were especially sensitive to L-type channel block, but not affected by block of omega-conotoxin-GVIA-sensitive CaV channels or TTX-sensitive voltage-gated Na+ (Nav) channels. A population of 17B-Estradiol-treated cells exhibited enhanced spontaneous Ca2+ oscillation amplitude and frequency and depolarization-evoked Ca2+ transients. E2 treatment significantly enhanced the Ca2+ response through dihydropyridine-sensitive voltage-gated Ca2+ (Cav) channels, suggesting that 17B-Estradiol increased L-type Ca2+ channel genomic expression.

Provenance

Recieved from ProQuest

Rights holder

Monika Pauckova

File size

57 p.

File format

application/pdf

Language

en

Discipline

Biology

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