Abstract
Prolactin (PRL) release and intracellular free calcium concentration [Ca2+]i were measured in two populations of normal rat lactotrophs (light and heavy fractions) in culture. Spontaneous PRL release of heavy fraction cells was more sensitive to dihydropyridines (DHPs; Bay K 8644 and nifedipine) when compared to the light fraction lactotrophs. The stimulatory effect of thyrotropin-releasing hormone (TRH) on PRL release from heavy fraction cells was inhibited by Cd2+ and mimicked by Bay K 8644. Indo-1 experiments revealed that TRH-increased [Ca2+]i was reversibly inhibited by Cd2+. In a Ca(2+)-free EGTA-containing medium, TRH did not modify [Ca2+]i.
Publication types
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Comparative Study
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Research Support, Non-U.S. Gov't
MeSH terms
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3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester / pharmacology
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Animals
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Cadmium / pharmacology
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Calcium / metabolism*
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Calcium Channels / drug effects
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Calcium Channels / physiology
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Cells, Cultured
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Culture Media
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Cytoplasm / metabolism
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Dihydropyridines / pharmacology*
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Female
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Nifedipine / pharmacology
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Pituitary Gland, Anterior / drug effects
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Pituitary Gland, Anterior / metabolism*
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Prolactin / metabolism*
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Rats
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Rats, Wistar
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Thyrotropin-Releasing Hormone / pharmacology*
Substances
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Calcium Channels
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Culture Media
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Dihydropyridines
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Cadmium
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Thyrotropin-Releasing Hormone
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3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
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Prolactin
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Nifedipine
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Calcium