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Phospholipase C‐β and ovarian sex steroids in pig granulosa cells
Author(s) -
Lieberherr Michèle,
Grosse Brigitte,
Machelon Véronique
Publication year - 1999
Publication title -
journal of cellular biochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.028
H-Index - 165
eISSN - 1097-4644
pISSN - 0730-2312
DOI - 10.1002/(sici)1097-4644(19990701)74:1<50::aid-jcb6>3.0.co;2-i
Subject(s) - androstenedione , medicine , endocrinology , phospholipase c , pertussis toxin , endoplasmic reticulum , calcium in biology , calcium , phospholipase , chemistry , biology , g protein , receptor , hormone , microbiology and biotechnology , biochemistry , androgen , enzyme
We compared the membrane effects of estradiol, progesterone, and androstenedione in a single experimental model, the ovarian granulosa cells collected from immature Large White sows. We measured changes in cytosolic free calcium concentration ([Ca 2+ ]i) in confluent Fura‐2 loaded cells. We used pharmacological tools and polyclonal phospholipase C‐β (PLC‐β) antibodies. Each steroid (0.1 pM to 1 nM) transiently increased intracellular calcium concentration ([Ca 2+ ]i) within 5 sec. They mobilized Ca 2+ from the endoplasmic reticulum as shown by using two phospholipase C inhibitors, neomycin and U‐73122. Ca 2+ mobilization involved PLC‐β1 for progesterone, PLC‐β2 for estradiol and PLC‐β4 for androstenedione. A pertussis toxin‐insensitive G protein was involved in the effects of progesterone on Ca 2+ mobilization whereas estradiol and androstenedione effects were mediated via a pertussis toxin‐sensitive G‐protein. Ca 2+ influx from the extracellular milieu was involved in the increase in [Ca 2+ ]i induced by progesterone and estradiol, but not by androstenedione. Influx of Ca 2+ was independent of Ca 2+ mobilization from calcium stores, and it was suggested that L‐type Ca 2+ channels for estradiol and T‐type Ca 2+ channels for progesterone were involved. The three steroids had no effect on cAMP. Rapid effects of progesterone, estradiol, and androstenedione involved a direct action on cell membrane elements such as PLC‐β, G‐proteins, and calcium channels, and these mechanisms were hormone‐specific. J. Cell. Biochem. 74:50–60, 1999. © 1999 Wiley‐Liss, Inc.