Ghrelin-Induced Enhancement of Vasopressin and Oxytocin Secretion in Rat Neurohypophyseal Cell Cultures.

The effects of ghrelin on vasopressin and oxytocin secretion were studied in 13-14-day cell cultures of isolated rat neurohypophyseal tissue. The vasopressin and oxytocin contents of the supernatant were determined by radioimmunoassay after a 1- or 2-h incubation. Significantly increased levels of vasopressin and oxytocin production were detected in the cell culture media following ghrelin administration, depending on the ghrelin doses. The oxytocin level proved to be more elevated than that of vasopressin. The increase of vasopressin and oxytocin secretion could be totally blocked by previous administration of the ghrelin receptor antagonist ([D-Lys3]-growth hormone-releasing peptide-6). Application of the ghrelin receptor antagonist after ghrelin administration proved ineffective. The results indicate that vasopressin and oxytocin release is influenced directly by the ghrelin system, and the effects of ghrelin on vasopressin and oxytocin secretion from the neurohypophyseal tissue in rats can occur at the level of the posterior pituitary. Our observations lend support to the view that neurohypophysis contains ghrelin receptors.

[Polyresistant Streptococcus pneumoniae causing cumulative diseases in infants and young children]. / Polirezisztens Streptococcus pneumoniae által okozott halmozott megbetegedések csecsemökben és kisdedekben.

Eight cases are reported here. Isolated Penicillin resistant Streptococcus pneumoniae strains were also resistant to Oxacillin, Erythromycin, Ampicillin, Cotrimoxazole. In five cases resistance to second generation cephalosporines (Cefaclor, Cefuroxime) also could be demonstrated. All of these multiply resistant strains retained their susceptibility to the third generation cephalosporines (Cefotaxime, Ceftriaxone). Claforan treatment resulted recovery in all of the patients.