PMID- 21153267
OWN - NLM
STAT- PubMed-not-MEDLINE
DCOM- 20121002
LR  - 20211020
IS  - 1355-008X (Print)
IS  - 1355-008X (Linking)
VI  - 4
IP  - 2
DP  - 1996 Apr
TI  - Spontaneous and agonist-induced calcium oscillations in single human 
      nonfunctioning adenoma cells.
PG  - 123-32
LID - 10.1007/BF02782757 [doi]
AB  - The effects of gonadotropin-releasing hormone (GnRH) and GnRH-associated peptide 
      (GAP) on cytosolic free calcium concentration ([Ca(2+)](i)) were investigated in 
      20 human nonfunctioning pituitary adenomas. We divided these tumors into three 
      classes according to their response pattern to hypothalamic peptides. In type I 
      adenomas (8 out of 20 adenomas), GnRH and GAP mobilized intracellular calcium 
      ions stored in a thapsigargin (TG)-sensitive store. For the same concentration of 
      agonist, two distinct patterns of GnRH-GAP-induced Ca(2+) mobilization were 
      observed (1) sinusoidal oscillations, and (2) monophasic transient. The latter is 
      followed by a protein kinase C (PKC)-dependent increase in calcium influx through 
      L-type channels. In type II adenomas (7 out of 20 adenomas), GnRH and GAP only 
      stimulate calcium influx through dihydropyridine-sensitive Ca(2+) channels by a 
      PKC-dependent mechanism. TG (1 muM) did not affect [Ca(2+)](i) in these cells, 
      suggesting that they do not possess TG-sensitive Ca(2+) pools. All the effects of 
      GnRH and GAP were blocked by an inhibitor of phospholipase C (PLC), suggesting 
      that they were owing to the activation of the phosphoinositide turnover. Type I 
      and type II adenoma cells showed spontaneous Ca(2+) oscillations that were 
      blocked by dihydropyridines and inhibition of PKC activity. GnRH and GAP had no 
      effect on the [Ca(2+)](i) of type III adenoma cells that were also characterized 
      by a low resting [Ca(2+)](i) and by the absence of spontaneous Ca(2+) 
      fluctuations. K(+)-induced depolarization provoked a reduced Ca(2+) influx, 
      whereas TG had no effect on the [Ca(2+)](i) of type III adenoma cells. The 
      variety of [Ca(2+)](i) response patterns makes these cells a good cell model for 
      studying calcium homeostasis in pituitary cells.
FAU - Vacher, P
AU  - Vacher P
AD  - Laboratoire de Neurophysiologie, CNRS URA 1200, Universite de Bordeaux 2, 146 rue 
      Leo Saignat, PB 22, 33076, Bordeaux Cedex, France.
FAU - Bresson-Bepoldin, L
AU  - Bresson-Bepoldin L
FAU - Dufy-Barbe, L
AU  - Dufy-Barbe L
FAU - Odessa, M F
AU  - Odessa MF
FAU - Guerin, J
AU  - Guerin J
FAU - Dufy, B
AU  - Dufy B
LA  - eng
PT  - Journal Article
PL  - United States
TA  - Endocrine
JT  - Endocrine
JID - 9434444
EDAT- 1996/04/01 00:00
MHDA- 1996/04/01 00:01
CRDT- 2010/12/15 06:00
PHST- 1995/07/06 00:00 [received]
PHST- 1996/01/17 00:00 [accepted]
PHST- 1995/11/14 00:00 [revised]
PHST- 2010/12/15 06:00 [entrez]
PHST- 1996/04/01 00:00 [pubmed]
PHST- 1996/04/01 00:01 [medline]
AID - 10.1007/BF02782757 [doi]
PST - ppublish
SO  - Endocrine. 1996 Apr;4(2):123-32. doi: 10.1007/BF02782757.