Responsiveness of Irradiated Rat Anterior Pituitary Cells to Hypothalamic Releasing Hormones Is Restored by Treatment with Growth Hormone

2000 ◽  
Vol 72 (6) ◽  
pp. 392-399 ◽  
Author(s):  
Andrea Chiarenza ◽  
Laurence Lempereur ◽  
Tullio Palmucci ◽  
Giuseppina Cantarella ◽  
Matilde Amico-Roxas ◽  
...  
Keyword(s):  
Growth Hormone ◽  
Anterior Pituitary ◽  
Pituitary Cells ◽  
Anterior Pituitary Cells ◽  
Hypothalamic Releasing Hormones

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.

scholarly journals Detection of insulin synthesis in mammalian anterior pituitary cells by immunohistochemistry and demonstration of insulin-related transcripts by in situ RNA-DNA hybridization.

1986 ◽  
Vol 34 (5) ◽  
pp. 673-678 ◽  
Author(s):  
G C Budd ◽  
B Pansky ◽  
B Cordell
Keyword(s):  
Growth Hormone ◽  
Nucleic Acid ◽  
Dna Hybridization ◽  
Anterior Pituitary ◽  
Secretory Granules ◽  
Pituitary Cells ◽  
Insulin Synthesis ◽  
Anterior Pituitary Cells ◽  
Pancreatic B Cells

Insulin or highly homologous transcripts is shown to be synthesized in cultures of mammalian anterior pituitary cells using cloned insulin-specific cDNA probes and nucleic acid cytochemistry. The insulin-hybridizing cells are less abundant than the growth hormone-producing cells, occurring in the cultures at approximately one tenth the frequency. Immunocytochemistry demonstrates that insulin or insulin-like proteins is also synthesized by the cultured pituitary cells and that the insulin immunoreactivity is contained within secretory granules. It appears that many of these secretory granules are concentrated around the periphery of the cell, unlike the insulin-containing granules in pancreatic B-cells.

Sign in / Sign up

Export Citation Format

Share Document