Morphological study of the pituitary gland of the studanese Nile fish Clarias Lazera

C. lazera was studied using some standard techniques employed in the study of vertebrate pituitary. The pituitary gland is attached to the infundibular region of the brain by a cylindrical infundilbular stalk. The gland is composed of two main divisions; the pars glandularis and the pars nervosa. The former is subdivided into an anterior, middle and posterior glandular regions. The anterior glandular region is composed mostly of clusters of acidophils which surround blood capillaries, giving the region a follicular appearance. The middle region is composed of basophils, acidophils and chromophobes. The distribution of the three types of cells has no definite pattern. The basophils are characterized by possessing colloidal globules, and therefore such basophils are described as globular basophils. The posterior region is formed mostly of dull acidophils, with few interspersed dull faint basophils. The two types of cells are scattered singly or in groups arround the branches of the pars nervosa. The pars nervosa, which is the continuation of the infundibular stalk, form a central core around which the three glandular regions of the pituitary gland are arranged. The processes of the pars nervosa are elaborate, with a fanning root – like nature, in the posterior glandular region and scanty in both the anterior and middle glandular regions. The pars nervosa appears as a fibrous tissue with scattered nuclei belonging to neuroglia cells. It is characterized by the colloidal Herring materials, basophil and acidophilic glandular cells. Infundilbular stalk, which link the floor of hypothalamus and the terminal zone of the anterior glandular region was found to be a thin lamina of nervious tissue with a layer of epindymal cell lining the third ventricle. The middle glandular region was found to consist of three chromophils cells, only one type of acidophil was identified. It took both OG and erythrosin. The other two types were found to be basophilic and they were designated as type 2 and type 3. Basophils type 3 were PAS, AF positive but AB negative. The pars nervosa was found to be small, and contained more stainable neuro-secretory materials.

The evaluation of pituitary damage associated with cardiac arrest: An experimental rodent model

The pituitary gland plays an important endocrinal role, however its damage after cardiac arrest (CA) has not been well elucidated. The aim of this study was to determine a pituitary gland damage induced by CA. Rats were subjected to 10-min asphyxia and cardiopulmonary resuscitation (CPR). Immunohistochemistry and ELISA assays were used to evaluate the pituitary damage and endocrine function. Samples were collected at pre-CA, and 30 and 120 min after cardio pulmonary resuscitation. Triphenyltetrazolium chloride (TTC) staining demonstrated the expansion of the pituitary damage over time. There was phenotypic validity between the pars distalis and nervosa. Both CT-proAVP (pars nervosa hormone) and GH/IGF-1 (pars distalis hormone) decreased over time, and a different expression pattern corresponding to the damaged areas was noted (CT-proAVP, 30.2 ± 6.2, 31.5 ± 5.9, and 16.3 ± 7.6 pg/mg protein, p < 0.01; GH/IGF-1, 2.63 ± 0.61, 0.62 ± 0.36, and 2.01 ± 0.41 ng/mg protein, p < 0.01 respectively). Similarly, the expression pattern between these hormones in the end-organ systems showed phenotypic validity. Plasma CT-proAVP (r = 0.771, p = 0.025) and IGF-1 (r = −0.775, p = 0.024) demonstrated a strong correlation with TTC staining area. Our data suggested that CA induces pathological and functional damage to the pituitary gland.

Expression, distribution, regulation and function of IGFs in the ovine fetal pituitary

ABSTRACT Activation of the fetal pituitary-adrenal axis is crucial for fetal organ maturation and the onset of parturition in sheep. Many factors including corticotrophin-releasing hormone (CRH) and arginine vasopressin secreted from the hypothalamus, and growth factors produced within the pituitary may be involved in the regulation of maturation of the fetal pituitary gland. IGFs have mitogenic and differentiation-promoting capacities in a variety of organs and are synthesized as paracrine factors within developing tissues. However, there is little information concerning the synthesis, distribution, regulation and function of IGFs in the fetal pituitary gland at different times during pregnancy. Therefore, we have localized IGF-I and IGF-II mRNAs and peptides, and determined the effect of cortisol on the level of IGF-II mRNAs in the pituitary glands of developing sheep fetuses. We examined the possible effects of IGFs on corticotroph function in cultures of adenohypophysial cells from term fetuses. Seven species of IGF-II transcripts of 1·2–6·0 kb were identified by Northern blot analysis in the pituitary gland of fetuses between day 60 of gestation and term (day 145). The levels of IGF-II mRNAs did not change significantly during pregnancy, although there was a trend for the presence of higher levels of IGF-II mRNAs at day 60 of gestation. IGF-I mRNA was not detectable. By in situ hybridization, IGF-II mRNA was localized to non-endocrine cells and to cells lining the blood vessels of the pars distalis, to some presumed endocrine cells in the pars distalis and pars intermedia, and to clusters of cells in the pars nervosa. In contrast, IGF-I and IGF-II peptides were detected in the presumed endocrine cells in the pars distalis and pars intermedia but not in the pars nervosa. Incubation of adenohypophysial cells from term fetuses with IGF-I, but not IGF-II, for 48 h increased specific 125I-Tyr-ovine CRH binding. However, neither IGF-I nor IGF-II had any significant effects on the basal or CRH-stimulated immunoreactive (ir)-ACTH output, the level of POMC mRNA or the number of ir-ACTH positive cells. Infusion of cortisol to fetuses starting at day 96 of gestation for 100 h or at days 120–125 of gestation for 84 h did not affect the level of IGF-II mRNAs in the pars distalis but decreased the levels of POMC mRNA. These results are consistent with IGFs having the potential to influence fetal pituitary function, although probably on cell types other than the corticotrophs. The likely sources of IGFs may be predominantly local (IGF-II) or from extrapituitary sources (IGF-I).