Calcium currents and fura-2 signals in fluorescence-activated cell sorted lactotrophs and somatotrophs of rat anterior pituitary

D. L. Lewis, M. B. Goodman, Paul A St John, J. L. Barker

Research output: Contribution to journalArticle

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Abstract

Optical and electrical recording techniques were applied to single primary pituitary cells to characterize the types of voltage-dependent calcium currents (I(Ca)) and levels of intracellular calcium ([Ca2+](i)). GH-containing somatotrophs and PRL-containing lactotrophs were isolated from adult female rats using fluorescence-activated cell-sorting techniques and were maintained in culture for 1-4 days. Whole cell patch-clamp recordings were made to analyze the I(Ca), and [Ca2+](i) was measured with fura-2. Cell type was verified after each recording by indirect immunocytochemistry. GH and PRL cells could be divided into two groups: silent and spontaneously active. Silent cells had stable membrane potentials and stable levels of [Ca2+](i). Spontaneously active cells exhibited spontaneous action potentials and large fluctuations in [Ca2+](i). Two types of I(Ca) were found: a low threshold, transient current which was insensitive to the dihydropyridine -Bay 5417 (the negative isomer of Bay K 8644), and a high threshold, sustained current which was enhanced by -Bay 5417. Both types of I(Ca) were present in PRL and GH cells, but each cell type differed quantitatively in the proportion of each current type. While the GH cells had a more prominent, low threshold, transient I(Ca), the PRL cells had a more prominent, high threshold, sustained I(Ca). The enhancement of I(Ca) by -Bay 5417 was greater in the PRL cells, which have a larger dihydropyridine-sensitive I(Ca). Parallel fura-2 measurements showed an increase in [Ca2+](i) in response to 50 mM KCl and -Bay 5417 for both lactotrophs and somatotrophs.

Original languageEnglish (US)
Pages (from-to)611-621
Number of pages11
JournalEndocrinology
Volume123
Issue number1
StatePublished - 1988
Externally publishedYes

Fingerprint

Lactotrophs
Somatotrophs
Fura-2
Fluorescence
Calcium
3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethyl-5-nitro-4-(2-(trifluoromethyl)phenyl)-, Methyl ester
Membrane Potentials
Action Potentials
Flow Cytometry

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism

Cite this

Calcium currents and fura-2 signals in fluorescence-activated cell sorted lactotrophs and somatotrophs of rat anterior pituitary. / Lewis, D. L.; Goodman, M. B.; St John, Paul A; Barker, J. L.

In: Endocrinology, Vol. 123, No. 1, 1988, p. 611-621.

Research output: Contribution to journalArticle

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