[The role of Ca2+ in the pathogenesis of human pituitary GH-secreting adenomas].
Effects of Ca2+ channel blockers (nicardipin and nifedipin) and Ca2+ ionophore A23187 on the basal secretion and on the secretion stimulated by GRH or inhibited by SMS, a SRIF analogne of GH were investigated in monolayer cell cultures of 23 cases of human pituitary GH-secreting adenomas. The roles of GRH and SMS in 45Ca influx were investigated also. The GH secretion of most GH adenomas was depended on Ca2+, but the abnormality in different link of GH secretion mediated by Ca2+ was observed. The defects of receptor and post-receptor including Ca2+ channel and Ca(2+)-GH secretion couple regulated by GRH and SRIF were found in 66.7% and 55.6% of GH adenomas respectively. These abnormalities may contribute to GH hypersecretion in GH adenomas.
Yin
J
J
PUMC Hospital, CAMS, Beijing.
Deng
J
J
Shi
Y
Y
Shu
C
C
D000236:Adenoma / Q000378:metabolism* / Q000473:pathology; D001693:Biological Transport, Active / Q000187:drug effects; D000001:Calcimycin / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology; D006801:Humans; D007476:Ionophores / Q000494:pharmacology; D009529:Nicardipine / Q000494:pharmacology*; D009543:Nifedipine / Q000494:pharmacology; D015282:Octreotide / Q000031:analogs & derivatives / Q000494:pharmacology; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D013004:Somatostatin / Q000819:agonists; D014407:Tumor Cells, Cultured
D002121:Calcium Channel Blockers; D007476:Ionophores; C045210:3-Tyr-octreotide; D000001:Calcimycin; D013004:Somatostatin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D009529:Nicardipine; D009543:Nifedipine; D015282:Octreotide; D002118:Calcium