Arachidonic acid is a slippery molecule that owes its mobility to its four cis double bonds. These are the source of its flexibility, keeping the pure fatty acid liquid, even at subzero temperatures, and helping to give mammalian cell membranes their correct fluidity at physiological temperatures. The double bonds are also the key to the propensity of arachidonic acid to react with molecular ox...

Human milk contains many different components which interact locally in the gastrointestinal tract and stimulate some systemic functions. Among these substances are prostaglandins. We obtained samples of foremilk and hindmilk in 8 lactating women by manual expression before and after 9 a.m. and 9 p.m. on the 3rd day post partum. The following values were found for prostaglandin E2: foremilk, 16...

Metabolism of free (nonesteriRed) arachidonic acid (5,8,11,14-cis-eicosatetraenoic acid) via the cyclooxygenase (COX) pathway produces a cascade of biologically active compounds collectively known as prostaglandins (PGs). These include prostaglandin D2 (PGD2), prostaglandin E2 (PGE2), prostaglandin F2 (PGF2), prostacyclin (PGI2) and thromboxane A2 (TXA2) (Figure 1). The analysis of PGs and rela...

Evidence accumulated using prostaglandin synthesis inhibitors, prostaglandin measurements, or prostaglandin antibodies in several species has supported the concept that a gonadotropin-induced preovulatory rise in follicular prostaglandins is required for ovulation. There are at least three questions which need to be answered for a further understanding of this requirement : 1) What is the mecha...

Prostaglandins are ephemeral, infinitesimal signallers self-regulating every cell in the body, including those sub-serving mood and immunity. At first, they were perceived as a master switch, but now are believed to regulate every component of cellular micro-anatomy and physiology, including those of the organelles, cytoskeleton, proteins, enzymes, nucleic acids and mitochondria. Prostaglandins...

Prostaglandins are known to enhance the inflammatory and nociceptive actions of other chemical mediators of inflammation such as bradykinin. One possible mechanism for this sensitizing action is that prostanoids augment the release of neuroactive substances from sensory neurons. To initially test this hypothesis, we examined whether selected prostaglandins could enhance the resting or bradykini...

Genes that are differentially expressed in pancreatic cancers and under epigenetic regulation are of considerable biological and therapeutic interest. We used global gene expression profiling and epigenetic treatment of pancreatic cell lines including pancreatic cancer cell lines, pancreatic cancer-associated fibroblasts, and cell lines derived from nonneoplastic pancreata. We examined expressi...

Nutritive and antimicrobial aspects of human milk have received considerable attention. However, another, as yet unproved role for breast milk has emerged in recent years: milk may contain factors which modify or supplement physiological functions in the neonate. For example milk lipase1 may assist in neonatal fat digestion, and hormones in milk-such as thyroxine2-may have biologically signific...

Chemoprevention has been considered as a possible approach for cancer prevention. A significant effort has been made in the development of novel drugs for both cancer prevention and treatment over the past decade. Recent epidemiological studies and clinical trials indicate that long term use of aspirin and similar agents, also called non-steroidal anti-inflammatory drugs (NSAIDs), can decrease ...

Two classes of arachidonic acid derivatives can be formed by two distinct enzyme systems. Cyclo-oxygenases synthesise prostaglandins, prostacyclin and thromboxane A2 which all possess both pro- and anti-inflammatory properties. Lipoxygenases synthesise on the one hand chemotactic factors, the hydroxylated derivatives of arachidonic acid, the most powerful of which is leukotriene B4, and on the ...