Prostaglandins in non-insectan invertebrates: recent insights and unsolved problems

Abstract

Prostaglandins, together with thromboxanes (collectively termed prostanoids), are fatty acid derivatives of significant importance in many physiological processes. These compounds are formed following the action of cyclooxygenases (COX) and associated enzymes on C20 polyunsaturated fatty acid precursors released from phospholipids in membranes. Nearly all mammalian cell types have the biosynthetic machinery to produce at least one type of prostanoid. The same C20 fatty acid substrates can also be acted upon by lipoxygenases to produce mono-di-and trihydroxy derivatives such as leukotrienes, lipoxins and resolvins. The final route is the cytochrome P 450 pathway that can convert C20 fatty acids to hydroxylated derivatives.Collectively these compounds are called eicosanoids; the term derived from the Greek eikosi that refers to the C20 backbone in the parent fatty acid.Prostaglandins (PGs) were first discovered in the 1930s by von Euler and colleagues, who found a substance produced by the prostate gland that caused smooth muscle contraction. They christened the active substance 'prostaglandin', but it was over 30 years until the structure and mode of biosynthesis of these fatty acid derivatives became fully understood. PGs have many basic physiological functions where they act as 'local' hormones. For example, thromboxane (Tx) A 2 and prostacyclin (PGI 2 ) generated by platelets and endothelial cells, respectively, regulate the aggregatory behaviour of

Role of Arachidonic Acid and COX Inhibitors in the Regulation of Reproduction in Freshwater Crab Oziothelphusa senex senex

“…Eicosanoids have an important role in the regulation of essential functions such as reproduction, haemostasis, growth, and the immune system in vertebrates. The occurrence of eicosanoids and their precursors have been identified in various invertebrates [1,2]. The presence of AA has been also identified in different crustaceans such as kuruma prawns, Penaeus japonicus and Marsupenaeus japonicus [3,4], green tiger prawn Penaeus semisulcatus [5], shrimps Penaeus monodon [6,7], Litopenaeus vannamei [8] and Penaeus merguiensis [9].…”

“…The presence of AA has been also identified in different crustaceans such as kuruma prawns, Penaeus japonicus and Marsupenaeus japonicus [3,4], green tiger prawn Penaeus semisulcatus [5], shrimps Penaeus monodon [6,7], Litopenaeus vannamei [8] and Penaeus merguiensis [9]. Furthermore, the presence of prostaglandins PGE 2 and PGF 2α were reported in Procambarus paeninsulanus [10], Marsupenaeus japonicus [4] and Penaeus monodon [11], whereas, only PGE 2 was reported in Carcinus maenas [12]. Along with PGE 2, and PGF 2α , PGD 2 also has been identified in the rice field crab Oziothelphusa senex senex [13].…”

Avaliação da presença de resíduos de anti‑inflamatórios não esteroides nos córregos veado e cedro do município de Presidente Prudente (SP), Brasil

“…Assim como as demais classes de medicamentos, os AI NEs também têm sido detectados no ambiente aquáti co com concentrações na faixa de ng.L 1 a µg.L 1 e, ape sar dessas baixas concentrações, estudos demonstram que tais compostos são biologicamente ativos (FENT; WESTON; CAMINADA, 2006) e interagem com a biota do meio, interferindo significativamente na fisiologia, no metabolismo e no comportamento das espécies (BELISÁRIO et al, 2009), A principal forma de atuação desses compostos é a inibição, de forma não seletiva, das enzimas ciclooxi genases (COX) 1 e 2, bloqueando a conversão do áci do araquidônico em prostaglandinas (SILVA & SILVA, 2012) que são responsáveis por diferentes funções fi siológicas, como por exemplo reprodução, transporte de água e regulação osmótica, nas quais atuam como hormônios locais (ROWLEY et al, 2005).…”

The identification and role of a novel eicosanoid in the reproductive behaviour of barnacles (Balanus balanus)

“…Furthermore, many marine invertebrates, such as corals, ascidians, bryozoans and barnacles, have been found to biosynthesize both 'classical' eicosanoids (i.e. those found in mammals) and novel forms including clavulones, mucosin, prostaglandin 1,15-lactones, and bromo-and iodo-vulones from these alternate fatty acid substrates (DiMarzo et al, 1991;Casapullo et al, 1997;Rowley et al, 2005). With a few notable exceptions (e.g.…”