Optical resolution of phosphorus containing calix[4]arenes by additive RP HPLC method.

The RP HPLC method (LiChrosorb RP18 or Separon SGX C18 column, acetonitrile-water 86:14 v/v mobile phase) was applied for enantiomeric separation of topologically chiral 5-bromo-25,26-bis(diethoxyphosphoryl)calix[4]arene 9 or 25-ethyl-26-dihydroxyphosphoryl-calix[4]arene 5. Separation of calixarene 9 was achieved by the addition of D-(-)-tartaric acid which formed hydrogen bonded diastereomeric associates with 9 to the mobile phase. Calixarenephosphoric acid 5 was transformed into diastereomeric salt 6 by addition of L-(-)-alpha-phenylethylamine before RP HPLC separation.

[Mutually potentiating effect of joint action of carbacholine and histamine on secretion and the isoenzyme spectrum of pepsin from frog gastric mucosa cells].

Pepsin secretion was studied in vivo in the primary culture of isolated secretory gastric mucosa cells of the frog (Rana ridibunda). The injection of animals with carbacholin (200 micrograms/100 g weight) or histamine (100 micrograms/100 g weight) or addition of the hormones (100 microM) into the incubation medium of isolated gastric cells significantly increased pepsin activity. In vitro, preliminary addition of the specific antagonists of these hormones to the incubation medium (1 microM atropine or 100 microM cimetidine) completely suppressed the effects of hormones.

[Participation of protein kinase C in hormonal regulation of pepsin secretion in the rat stomach].

It was shown that pentagastrin (0.5 micrograms/100 g of body mass) increases the activity of Ca2+ and phospholipid-dependent protein kinase C in the membrane fraction of rat gastric mucosa cells. This effect of pentagastrin is accompanied by a decrease of the protein kinase C activity in the cytosolic fraction.

[Secondary messengers in the hormonal regulation of the functional activity of the main and mucoid cells in the stomach].

The messenger role of Ca+2, cyclic nucleotides and inositol triphosphates in the stimulation of pepsinogen and mucous secretion were studied using isolated pig [correction of nug] gastric chief cells and guinea pig mucous cells, resp. Pepsinogen secretion was stimulated by agents either working at the postreceptor adenylate cyclase (AC) level (db-cAMP, forskolin) or after 12-o-tetradecanoyl-phorbol-13-acetate (TPA) stimulation of protein kinase C (PK C). Similar secretory effects were observed with histamine (H), carbachol (C) and cholecystokinin (CCK).

Biochemical mechanisms of regulation of mucus secretion by prostaglandin E2 in rat gastric mucosa.

The effects of prostaglandin E2 (PGE2) and inhibitors of RNA and protein synthesis on rat gastric mucosa were investigated in order to study the cellular and biochemical mechanisms involved in the PGE2-stimulated formation and secretion of gastric mucus. It was shown that PGE2 caused significant stimulation of gastric mucus secretion and this effect of PGE2 was inhibited by cycloheximide but not actinomycin D. The influence of PGE2 on the in vitro incorporation of N-acetyl-[3H]glucosamine and 14C-labelled amino acids in to the glycoproteins representing a major mucus component of the isolated gastric mucosa cells was also studied.