Effect of inhibitor and activator of ghrelin receptor (GHS-R1a) on porcine ovarian granulosa cell functions.

It was previously shown, that ghrelin and its agonistic analogue, ghrelin 1-18, can be a stimulator of ovarian cell functions (promoter of proliferation, inhibitor of apoptosis and stimulator of hormones release). The aim of our studies was to compare the action of two ghrelin analogues - ghrelin 1-18, activator of ghrelin receptors (GHS-R1a), and (D-Lys3)-GHRP-6, its inhibitor, on porcine ovarian granulosa cell functions. Effects of (D-Lys3)-GHRP-6 added at doses of 0, 1, 10 or 100 ng/ml on the expression of markers of proliferation (PCNA, cyclin B1, MAPK/ERK1,2), apoptosis (bax, p53, caspase 3) and release of steroid hormones (progesterone, testosterone, estradiol) were examined.

Differences in DNA damage and repair produced by systemic, hepatocarcinogenic and sarcomagenic dibenzocarbazole derivatives in a model of rat liver progenitor cells.

Liver progenitor (oval) cells are a potential target cell population for hepatocarcinogens. Our recent study showed that the liver carcinogens 7H-dibenzo[c,g]carbazole (DBC) and 5,9-dimethyldibenzo[c,g]carbazole (DiMeDBC), but not the sarcomagen N-methyldibenzo[c,g]carbazole (N-MeDBC), induced several cellular events associated with tumor promotion in WB-F344 cells, an in vitro model of liver oval cells [J. Vondracek, L.