Changes in intra- and extracellular Ca2+ concentration and prostaglandin E2 synthesis in osteoblasts of the femoral bone in experimental hyper- and hypothyroidism.
Subclinical form of hypothyroidism was not associated with considerable changes in Ca(2+) content in osteoblasts and blood plasma and in the content of ATP and prostaglandin E2. Activation of prostaglandin E2 synthesis in response to binding of extracellular Ca(2+) in osteoblasts in the absence of ATP was less pronounced (by 11%) compared to the control. Progression of hypothyroidism and development of clinical signs of the disease were accompanied by a decrease in Ca(2+) content in osteoblasts and plasma by 45 and 12%, respectively, and ATP content in osteoblasts by 30%, and by activation of prostaglandin E2 synthesis by 117%. Moreover, the synthesis of prostaglandins in response to binding of extra- and intracellular Ca(2+) also considerably changed. Hyperthyroidism (2 months) was characterized by a moderate decrease in plasma content of Ca(2+) by 15% and ATP by 25%, together with an increase in prostaglandin E2 level by 55.5%. The release of prostaglandin E2 in response to chelation of extracellular Ca(2+) increased even more markedly, but somewhat decreased in response to addition of 5 mM ATP due to compensation of metabolic acidosis.
Dolidze
N M
NM
Center of Rheumatology, Tbilisi.
Kezeli
D D
DD
Kilasoniya
L O
LO
D000818:Animals; D002118:Calcium / Q000378:metabolism*; D015232:Dinoprostone / Q000096:biosynthesis*; D005260:Female; D005269:Femur; D006706:Homeostasis; D006980:Hyperthyroidism / Q000139:chemically induced / Q000378:metabolism*; D007037:Hypothyroidism / Q000139:chemically induced / Q000378:metabolism*; D008297:Male; D010006:Osteoblasts / Q000378:metabolism*; D011441:Propylthiouracil; D051381:Rats; D013974:Thyroxine
D011441:Propylthiouracil; D015232:Dinoprostone; D013974:Thyroxine; D002118:Calcium