Peptide 204-212 of lipocortin 5 inhibits the generation of a prostacyclin-like factor from rat aorta preparations in vitro

Inhibition of smooth muscle contraction and platelet aggregation by peptide 204-212 of lipocortin 5: an attempt to define some structure requirements

Peptide 204-212 of lipocortin (LC) 5 inhibited porcine pancreatic phospholipase A(2) (PLA(2)) induced rat stomach strip contractions and ADP induced rabbit platelet aggregation in a concentration dependent manner (IC(30) of 10 muM and 400 muM, respectively). The first two amino acids are not necessary since the eptapeptide 206-212 was equipotent in both assays (IC(30) of 12.5 muM and 420 muM). Of the two pentapeptides 204-208 and 208-212 only the latter showed inhibitory activity in both models although the potency was much reduced (IC(30) of 170 muM and 630 muM) compared with that of the parent nonapeptide. Comparison of peptide 204-212 effects with those of its analogues on LC1 and LC2 indicate that lysine 208 and aspartic acid 211 are essential in order to maintain a fully active nonapeptide.

Small peptides Do not inhibit human non-pancreatic secretory phospholipase-A(2) (Type IIA)

Seven small peptides, that are among the most potent reported inhibitors of secreted mammalian phospholipases A(2), were found not to inhibit processing of a small phospholipid substrate by human non-pancreatic secretory phospholipase A(2) (type IIa), under conditions where certain non-peptides are potent inhibitors at nanomolar concentrations.

Inhibition of interleukin-1 beta-induced pyresis in the rabbit by peptide 204-212 of lipocortin 5

The intracerebroventricular administration of interleukin-1 beta (12.5 ng/kg) in rabbits caused a prompt rise of prostaglandin E2 concentration (+ 632.6 +/- 243.9%) in the cerebrospinal fluid followed by hyperthermia (+ 1.61 +/- 0.14 delta degrees C). The intracerebroventricular administration of an anti-inflammatory nonapeptide (amino acids 204-212, SHLRKVFDK) derived from lipocortin 5, thereafter referred to as lipocortin 5-(204-212)-peptide, inhibited in a significant manner both the increase in cerebrospinal fluid [prostaglandin E2] and the febrile response induced by the cytokine. This inhibitory effect is probably due to interference by the peptide with phospholipase A2 activity. A control peptide (FKRVHDLKS) formed by the same amino acids in a randomly shuffled sequence had no effect. These results show that, in addition to the anti-inflammatory effect previously reported, the peptide 204-212 of lipocortin 5 possesses, like glucocorticoids, anti-pyretic activity. The research on lipocortin-derived peptides may lead to the development of novel anti-inflammatory and anti-pyretic compounds.