[Effects of 17 beta-estradiol on intracellular free calcium, inositol-1,4,5-trisphophate and calmodulin in human osteoblast-like osteosarcoma cell line TE85].
OBJECTIVE
To study the effects of 17 beta-estradiol (E2) on intracellular free calcium ([Ca2+]i), inositol-1,4,5-trisphophate (IP3) and calmodulin (CaM) in human osteoblast-like cell line TE85.


METHODS
Using Fluo-3/AM as fluorescent indicator, the [Ca2+]i was measured by laser confocal microscopy system. The IP3 content was determined by anion-exchange chromatography. CaM content was detected by a high sensitive assay based on stimulation of Ca(2+)-dependent phosphodiesterase activity.


RESULTS
E2 at dose of 0.1 and 1.0 nmol/L increased fluorescent level by 4.7 and 6.1 times. Pretreatment with thapsigargin (100 nmol/L), the E2 caused only 1.5 times elevation in fluorescence. E2 induced a concommitant bi-peak increase in IP3 content. At the presence of E2(1.0 nmol/L), the CaM content increased by 85.2%. Tamoxifen did not affect the effect of E2 on [Ca2+]i, IP3 and CaM content. But, the inhibitor of phospholipase C (neomycin) and pertusis toxin depressed them partly or completely.


CONCLUSIONS
E2 regulate bone cells function by way of Ca2+/CaM activation.
Liu
J
J
Department of Pharmacology, Institute of Basic Medical Science, CAMS and PUMC, Beijing 100005.
Sun
L
L
Wang
Q
Q
Zheng
H
H
Wong
L
L
D000293:Adolescent; D001859:Bone Neoplasms / Q000473:pathology; D002118:Calcium / Q000378:metabolism*; D002147:Calmodulin / Q000378:metabolism*; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D006801:Humans; D015544:Inositol 1,4,5-Trisphosphate / Q000378:metabolism*; D010006:Osteoblasts / Q000378:metabolism*; D012516:Osteosarcoma / Q000473:pathology; D014407:Tumor Cells, Cultured
D002147:Calmodulin; D004958:Estradiol; D015544:Inositol 1,4,5-Trisphosphate; D002118:Calcium