Intracellular Calcium Concentration and Growth Hormone Secretion in Individual Somatotropes: Effects of Growth Hormone-Releasing Factor and Somatostatin*

Endocrinology ◽  
1988 ◽  
Vol 122 (6) ◽  
pp. 2927-2932 ◽  
Author(s):  
REINHARD W. HOLL ◽  
MICHAEL O. THORNER ◽  
DENIS A. LEONG
Keyword(s):  
Growth Hormone ◽  
Intracellular Calcium ◽  
Calcium Concentration ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Intracellular Calcium Concentration ◽  
Growth Hormone Releasing Factor

scholarly journals Spontaneous oscillations of intracellular calcium and growth hormone secretion.

1988 ◽  
Vol 263 (20) ◽  
pp. 9682-9685
Author(s):  
R W Holl ◽  
M O Thorner ◽  
G L Mandell ◽  
J A Sullivan ◽  
Y N Sinha ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Intracellular Calcium ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Spontaneous Oscillations

GRF elevates cytosolic free calcium concentration in rat anterior pituitary cells

1987 ◽  
Vol 253 (5) ◽  
pp. E591-E594
Author(s):  
C. Schofl ◽  
J. Sandow ◽  
W. Knepel
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Calcium Concentration ◽  
Hormone Secretion ◽  
Growth Hormone Secretion ◽  
Free Calcium ◽  
Pituitary Cells ◽  
Maximal Increase ◽  
Anterior Pituitary Cells ◽  
Free Calcium Concentration

The effect of human growth hormone-releasing factor (GRF) on intracellular free calcium concentration ([Ca2+]i) was examined in rat anterior pituitary cells. The [Ca2+]i was monitored directly by means of the intracellularly trapped fluorescent indicator, fura-2. GRF rapidly elevated [Ca2+]i, reaching a new plateau within approximately 30 s. The half-maximally effective concentration of GRF was approximately 130 pM. GRF produced a maximal increase in [Ca2+]i by approximately 120 nM. The GRF (2 nM)-induced elevation of [Ca2+]i was abolished by removal of extracellular calcium (Ca2+ omitted, 2 mM EGTA). The GRF (2 nM)-caused rise in [Ca2+]i was largely reduced in the presence of the calcium channel blockers Mg2+ (31.2 mM) or nifedipine (1 microM). An increase in [Ca2+]i by approximately 60 nM was elicited by the addition of prostaglandin E2 (1 microM), which can stimulate growth hormone secretion independent of GRF receptors. These data indicate that GRF elevates the [Ca2+]i, possibly in somatotrophs; this GRF-induced increase in [Ca2+]i may depend on an influx of extracellular Ca2+, largely through Mg2+- and nifedipine-sensitive calcium channels.

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