Article Type
Original Study
Abstract
The requirement of extra and/or in-tracellular CQ++ to stimulate prosta-glandins synthesis varies in different tissues . Poyser, (1985), elicited that prosta-gtandins synthesis and efflux from their active biosynthetic sites in almost tissues is dependent upon mobilization of Ca++ from intracellular stores. The extracellular Ca++ is essential for release of Ca++ from intracellular stores and essential for replenish these stores., Rilley & Poyser, (1987). Ernest et al.. (1983), reported that the activity of phospholipase seems to be increased by the presence of Ca++. PLA2 is extremly important in the release of arachidontc acid, (which is the most abundent of prostaglandins precursors in almost all the tissues), followed by a rise of prostaglandins biosynthesis. So PLA2 is considered as a regulating and triggering enzyme for prostaglandins biosynthesis. Prostagiadins are not stored preformed but are synthesized and released as required. Therefore the increased efflux reflects the increased biosynthesis and not release of prost-glandins as endogenous constituents Ramwell & Shaw, 1970 and Olley & Coceani, (1980). Synthesis of PGF2 & may be derived from PGE2 and/or from PGD2. The in-terconversion between PGF2 & and PGFg is dought, Yamamoto, (1983), reported that there is no a direct inter-conversion between PGE2 and PGF2 &. In contrast Ernest et al., (1983) found that reduction of the Ketogroup at Cg in PGE2 to form PGF2 & compound is found to take place in guinea pig as weil as in human.
Recommended Citation
Hafez, Tarek; Sayed, S; Nada, Hoda; and AboAzma, Saad
(1990)
"EFFECT OF EXOGENOUS CALCIUM IONS ON PROSTAGLANDINS OUTPUT FROM RAT HEPATIC: TISSUE SLICES,"
Mansoura Medical Journal: Vol. 19
:
Iss.
1
, Article 7.
Available at:
https://doi.org/10.21608/mjmu.1990.138760
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