Browsing by Subject "Bombesin"

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    Effects of bombesin and neuromedin-B on the proliferative activity of the rat adrenal cortex
    (Murcia : F. Hernández, 1993) Markowska, A.; Nussdorfer, G.G.; Malendowicz, L.K.
    Bombesin (BM) and neuromedin-B (NMB) exert similar biological effects, acting via two functionally distinct BM-receptor subtypes. The present study aimed to investigate whether BM and NMB stimulate the proliferation of rat adrenocortical cells and to compare their mode of action. Adult female rats were treated with a single subcutaneous dose of 3 pg BM or NMB. Adrenocortical proliferative activity was assessed by the metaphase-arrest technique. BM administration resulted in a marked increase in the number of metaphases in zona glomerulosa (ZG) and zona fasciculata (ZF), and in the entire cortex. This increase appeared 24 h after injection in the ZG, and after 48 h in the ZF. NMB adrninistration, on the other hand, caused a prompt increase in the number of metaphases in the ZG and entire cortex at 12 h, followed by a subsequent drop below the control leve1 at 24 and 48 h of experiment. These findings indicate that BM and NMB enhance the proliferative activity of rat adrenocortical cells acting via different receptors or different mediators.
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    Effects of bombesin on the morphology and
    (Murcia : F. Hernández, 1995) Malendowicz, L.K.; Nussdorfer, G.G.; Miskowiak, B.; Majchrzak, M.
    The acute and chronic effects of bornbesin (BM) on the structure and function of rat adrenal cortex were investigated by rnorphornetric and radioirnrnunological techniques. An intraperitoneal bolus injection of 2 yglrat BM rnarkedly raised plasma corticosterone (B) concentration (PBC). The intraperitoneal BM infusion (1 yg/rat.h-l) for 1, 2 or 4 days evoked a notable increase in the nurnber of adrenocortical cells, without inducing apparent changes in either PBC or B output by adrenal quarters. Since proliferation and expression of specialized functions are rnutually exclusive states of cells, our findings suggest that the conspicuous stirnulation of adrenocortical-cell proliferation evoked by BM infusion may be responsible for the apparent lack of effect of this treatrnent on B secretion.