Morfometrijske i funkcionalne promene somatotropnih ćelija hipofize ženki pacova posle centralne aplikacije somatostatina

Abstract

This study examined the effects of intracerebroventricularly (i.c.v.) administered somatostatin (SRIH-14 orSRIH-28) on growth and function of pituitary somatotropes (GH cells). Female rats were subjected to intracerebroventricular administration of three 1g doses of SRIH-14 or SRIH-28 every second day. Blood samples were collected for hormone analyses and pituitaries were removed for histological and morphometric evaluation, five days after the last injection. Compared to control animals, SRIH treatment decreased (p<0.05) all morphometric measurements obtained for GH cells. The concentration of serum growth hormone (GH) in SRIH-14- or SRIH-28-treated groups was lower (p<0.05) by 69% and by 61% respectively, in comparison to control rats. These findings suggest that centrally administered somatostatin is specifically involved in the control of growth and secretory activity of GH cells. Thus, pharmacological manipulation of SRIH receptors reached from cerebrospinal fluid may alter the systemic effects of GH.

Ispitivani su efekti intracerebroventrikularno (i.c.v.) ubrizganih somatostat-ina (SRIH-14 ili SRIH-28) na rast i funkciju somatotropnih ćelija hipofize ženki pacova. Sve eksperimentalne životinje su primale po 1μg SRIH-14 ili SRIH-28 rastvorenog u 5μL fiziološkog rastvora, svaki drugi dan. Kontrole su na isti način injecirane fiziološkim rastvorom. Životinje su žrtvovane petog dana po poslednjoj primljenoj dozi. Krv je sakupljana za određivanje koncentracije hormona rasta (GH) u serumu, a hipofize su pripremane za histološku i morfometrijsku analizu. Dobijeni rezultati pokazuju da SRIH tretirane životinje pokazuju značajno smanjenje (p<0.05) svih ispitivanih morfometrijskih parametara (volumen ćelija i jedara, volumenska gustina) u odnosu na kontrolu. Koncentracija GH u serumu SRIH-14 i SRIF-28 tretiranih ženki takodje je značajno smanjena(p<0.05)za69%odnosno 61% u poređenju sa kontrolnim ženkama. Na osnovu ovako dobijenih rezultata može se zaključiti da oba aplikovana somatostatina inhibiraju rast i sekretornu aktivnost somatotropnih ćelija hipofize.