Concentration of prostaglandins

Pandey, H. P et al. (1995). Concentration of prostaglandin D2 in cerebrospinal fluid exhibits a circadian alteration in conscious rats. Biochem. Molec. Biol. Int. 37, 431-7. 

Vitamin E (tocopherol) possesses antioxidative properties, which means it can protect polyunsaturated fatty acids from auto-oxidation. Deficiency of vitamin E causes increased peroxidation of lipids, which consequently leads to elevated production of prostaglandins. Increased concentration of prostaglandins, in turn, retards... 

TWG exhibited a significant anti-inflammatory effect on acute agar-induced edema of the rat paw and suppressed carrageenan-induced inflammation in vivo. The number of exudate cells and the concentration of Prostaglandin E2 (PGE2), nitrite and TNF-oc in the... 

Maathuis JB and RW Kelly. Concentration of prostaglandins F2 and E2 in endometrium throughout the human menstrual cycle after the administration of clompi-phene or an oestrogen-progesterone pill and in early pregnancy. J Endocrinol 77 361, 1978. 

D.H.Nugteren 1. The concentration of prostaglandins of the E Series in the blood is very low and is not detectable with most assays. 

In this way, aspirin functions as an acetylating agent, which effectively deactivates the enzymes, thereby inhibiting the production of prostaglandins. With a decreased concentration of prostaglandins, the onset of inflammation is slowed, and fevers are reduced. 

A 38-year-old man with acute promyelocytic leukemia who was taking itraconazole 200 mg bd was given all-trans retinoic acid and during the third course of maintenance therapy developed acute renal insufficiency and symptomatic hypercalcemia, which was treated with high-volume crystalloid infusions and furosemide. Renal function was restored, and the serum calcium concentration returned to normal within 4 days after withdrawal of ATRA. The peak serum calcium concentration was 3.67 mmoUl. Serum parathyroid hormone was undetectable, and there were no increases in the concentrations of prostaglandins or vitamin D metabolites. Hypercalcemia recurred during a fourth course of ATRA. 

Absorption spectroscopy provides an opportunity to follow concentrations of individual species with time by observing the system at more than one wavelength. An example is the dehydration of prostaglandin E methyl ester, in which the essential chemistry is shown as follows ... 

Cyclooxygenase (COX) activity is responsible for the formation of prostaglandins from their arachidonic acid precursor. Two COX isoforms have been identified, COX-1 and COX-2. While COX-1 is constitutively expressed in most tissues, COX-2 is typically only found after induction by proinflammatory stimuli. However, a constitutively expressed and highly regulated COX-2 is found in the kidney, both in the renal medulla and in the renal cortex. Renal cortical COX-2 is located in the area ofthe juxtaglomerular apparatus, and prostaglandins formed by COX-2 regulate the expression and secretion of renin in response to a reduction in NaCl concentration at the macula densa. 

A molecular variation of plasma membrane has been reported by Puccia et al. Reduction of total lipids (XL) content and significant variations of triglyceride (TG) and phospholipids (PL) fractions were observed as a consequence of exposure of C. intestinalis ovaries to TBTCl solutions. In particular, an evident TG decrease and a PL increase were observed, which probably provoked an increment in membrane fluidity, because of the high concentration of long chain fatty acids and, as a consequence, PL. This could be a cell-adaptive standing mechanism toward the pollutants, as observed in Saccharomyces cerevisiae. Also the increase in the content of the polyunsaturated fatty acids (PUPA), important in the synthesis of compounds such as prostaglandin which are present in the ovary in a stress situation, was probably a consequence of a defense mechanism to the stress provoked by the presence of TBTCl. 

The main problem with any study of prostaglandins (PGs) is that although brain concentrations can exceed 0.1 /rg/g, they appear to be formed on demand, rather than preformed and stored and they have very short half-lives (seconds). Also specific effective antagonists remain to be developed and PGs are widely and evenly distributed, unlike many NTs. Thus any analysis of their central effects rests heavily on either studying PG release, or their effects when applied directly (icv injection). Certainly the brain has the enzymatic ability to synthesise both prostaglandins (cycloxygenase) and leukotrienes (lypoxygenase) from arachidonic acid (AA) (see Fig. 13.8) and a number of central functions have been proposed for them (see Piomelli 1994). 

Hammarstrom, S., Hamberg, M., Samuelsson, B., Duell, E.A., Stawiski, M. and Voorhees, J.J. (1975). Increased concentrations of non-esterified arachidonic acid, 12L-hydroxy-5,8,10,14-eicosatetraenoic acid, prostaglandin E2 and prostaglandin F2 in epidermis of psoriasis. Proc. Natl Acad. Sci. USA 72, 5130-5134. 

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