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ATP, calcium uptake and growth hormone release
Author(s) -
Schofield J.G.,
Stead Margaret
Publication year - 1971
Publication title -
febs letters
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.593
H-Index - 257
eISSN - 1873-3468
pISSN - 0014-5793
DOI - 10.1016/0014-5793(71)80222-3
Subject(s) - citation , library science , computer science
The rate of growth hormone release from anterior pituitaries incubated in vitro can be increased by increasing the extracellular potassium ion concentration in the presence of calcium ions [l-3] . The rates of release of TSH [4], FSH and LH [S] , and ACTH [6,7] are also increased with increasing potassium ion concentration, but the rate of prolactin release is unchanged [6] . An increase in the extracellular potassium ion concentration has been shown to reverse the membrane potential of a proportion of anterior pituitary cells [7], and it is possible that this results in an increased influx of calcium raising the cytoplasmic free calcium concentration and hence triggering release. The stimulation of growth hormone release by high potassium concentrations is inhibited by CCCP (trichloromethoxycarbonylcyanide phenylhidrazone), an uncoupler of oxidative phosphorylation [ 1] . It is possible that this requirement of release for ATP is due to the direct involvement of ATP in the release process, although it might be mediated by an ATP involvement in calcium entry. We have therefore investigated the quantitative relation. ship between ATP concentration, growth hormone release and calcium incorporation into pituitary slices using various concentrations of 2,4-dinitrophenol and CCCP (uncouplers of oxidative phosphorylation), and rotenone (a respiratory chain inhibitor) to produce a range of ATP values.