Serosadeckzellen und Histiocyten

Ohne Zusammenfassung     

Opposite effects of cholecystokinin octapeptide (CCK-8) and tetrapeptide (CCK-4) after injection into the caudal part of the nucleus accumbens or into its rostral part and the cerebral ventricles

Neurons with colocalized cholecystokinin and dopamine are present predominantly in the ventral tegmental area and project mainly to the caudal part of the medial nucleus accumbens. The activity of this dopamine system can be evaluated by means of the intracranial self-stimulation behavior on male Wistar rats having chronic electrodes implanted into the medial forebrain bundle in the postero-lateral area of the hypothalamus. The direct injection of 150 pmol CCK-8 into the medio-caudal accumbens induced an increase of intracranial self stimulation while a similar administration into its rostral portion produced a slight decrease of intracranial self-stimulation. The administration of 300 pmol CCK-4 into the same medio-caudal part of the accumbens produced an inhibitory action on intracranial self stimulation lasting for 25 min. The injection of 70 to 1300 pmol CCK-4 into the cerebral ventricles produced no change on intracranial self-stimulation. The intracerebroventricular injection of 70 pmol CCK-8 induced a large decrease of intracranial self-stimulation lasting for 20 min. Sodium chloride 0.15 M or unsulphated CCK-8 injection were without effect in either case. These results support the ideas that intracerebroventricular CCK-8 injection inhibits accumbens dopaminergic activity but that CCK-8 injection into the medio-caudal part of the accumbens, where nerve terminals with colocalized CCK and DA are present, facilitates this dopaminergic activity. In addition at the level of medio-caudal accumbens, CCK-8 and CCK-4 have opposite effects.     

Diminished steroidogenic response of hamster granulosa cells to estrogen in vitro

Summary We have previously demonstrated that estrogen can exert inhibitory or atretogenic effects on the ovaries of both rats and rhesus monkeys in vivo. This study was designed to test whether the hamster (Mesocricetus auratus) is an appropriate model in which to test the effects of estrogens (diethylstilbestrol and estradiol-17) on steroid accumulation by ovarian granulosa cells in vitro, and whether the effects are similar to those demonstrated for other species in vivo. Immature female hamsters were injected with pregnant mare's serum gonadotropin at 28 to 30 days of age. Animals were sacrificed and follicular contents aspirated three days later. Granulosa cells were either left untreated or treated with diethylstilbestrol or estradiol (1×10^-7 M) in vitro for 72 h in the presence of androstenedione (1×10^-7 M), and in the presence or absence of serum (10%) or human follicle-stimulating hormone (20 ng/ml), and long-term accumulation of estrogen and progesterone was determined. Diethylstilbestrol inhibited accumulation of estrogen regardless of the presence or absence of follicle-stimulating hormone. In contrast, only estradiol plus follicle-stimulating hormone augmented accumulation of progesterone by granulosa cells. These findings that estrogen can be non-stimulatory or inhibitory to function of granulosa cells in vitro parallel those shown in vivo. Our experimental approach may therefore represent an appropriate model for study of the direct effects of estradiol on the function of granulosa cells.     

FSH-induced aromatase activity in hamster granulosa cells: effect of estradiol-17β in vitro

Summary We have shown previously that estradiol-17 (E₂) reduces number of ovulations in cyclic rats, induces atresia of the dominant preovulatory follicle in monkeys, and that the initial effects of this treatment include reduced viability and estrogen accumulation in vitro by aspirated granulosa cells (GC) from monkeys and hamsters. The present experiment was designed to determine whether the reduction in estrogen accumulation can be ascribed to a direct action of E₂ on the aromatization of androgen to estrogen in vitro. Female hamsters were injected with 30 I.U. pregnant-mare serum gonadotropin i.p. and sacrificed 3 days later. GC were aspirated from the largest follicles and incubated for 48 h (initial incubation period) in the presence of human pituitary follicle-stimulating hormone (hFSH, 100 ng/ml). Following initial incubation, GC were further incubated for up to 24 h (secondary incubation period). During this subsequent incubation, medium was supplemented with 100nM ³H-1-androstenedione (³H-A₄). Initial incubation with E₂ at doses of 10 ng/ml, 100 ng/ml and 1 m E₂/ml induced variability in GC response, and a maximal depression of 70%. The inhibition by E₂ of hamster GC function in vitro parallels that shown in vivo for both hamsters and monkeys, but contrasts with that shown for rats. Thus, hamsters may represent an appropriate model in which to study the atretogenic effects of E₂ directly on antral follicle development.     

Expression of binding sites for Dolichos biflorus agglutinin at the apical aspect of collecting duct cells in rat kidney

Summary To identify precisely the structural and functional cell type in the collecting duct of the rat kidney expressing binding sites for Dolichos biflorus agglutinin (DBA), we stained serial paraffin sections of kidney with horseradish peroxidase-labeled DBA and with immunocytochemical methods for localizing (Na⁺+K⁺)-ATPase and carbonic anhydrase II (CA II), enzymes found preferentially in principal and intercalated cells, respectively. Most principal cells expressing a strong basolateral staining for (Na⁺ + K⁺)-ATPase showed binding sites for DBA at their luminal surfaces. However, a minority of cells rich in CA II and showing morphologic characteristics of intercalated cells also expressed DBA binding sites at their luminal surface and apical cytoplasm. These data suggest that DBA cytochemistrycan provide a useful tool for studying the functional polarity of the main cell types of the collecting duct of the rat kidney.     

Expression of cell type-specific markers during pancreatic development in the mouse: implications for pancreatic cell lineages

Summary The islet cells of the mammalian pancreas are comprised of four different endocrine cell types, each containing a specific hormone. Islet cells also contain two enzymes of the catecholamine biosynthetic pathway: tyrosine hydroxylase (TH) and aromatic L-amino acid decarboxylase (AADC). The cell lineage relationships of these different cell types have not been examined and it is not known whether, during development, they originate from the same or from different precursor populations. In this study we used immunocytochemical procedures to determine whether developing pancreatic cells express markers common to endocrine and exocrine cell types. We found that acinar cell precursors express AADC prior to the appearance of an exocrine marker and that the expression of AADC in acinar cells persists throughout embryogenesis to the first month of postnatal life. At this time, acinar cells do not contain AADC. We also found that exocrine cells containing AADC never express other islet-cell markers. These findings suggest that while acinar and islet cells both arise from precursor cells containing AADC, these progenitor cells do not express a combined endocrine-exocrine phenotype.     

Calcitonin gene-related peptide immunoreactivity in airway epithelial cells of the human fetus and infant

Summary Calcitonin gene-related peptide-immunoreactive cells were identified within the epithelium of distal conducting airways in the human fetus and infant. Several peptides and amines, including calcitonin, have been identified previously within a specific population of airway epithelial cells. These cells, referred to as pulmonary neuroendocrine cells, are postulated to be airway chemoreceptors responsible for changes in ventilation and perfusion in response to changes in airway gas composition. Calcitonin gene-related peptide immunoreactive cells could be identified throughout the period of development studies (20 weeks gestation to 3 months of age), but were present in only limited numbers in less than 50% of individuals (n=23). In contrast, large numbers of calcitonin gene-related peptide immunoreactive cells were identified in 100% of infants (1–3 months, n=5) with bronchopulmonary dysplasia. The differential processing of mRNA transcribed from the calcitonin gene in neural and non-neural tissue suggests that calcitonin, rather than calcitonin gene-related peptide, is the primary product of translation in pulmonary neuroendocrine cells. However, considering the potent vasodilatory and bronchoconstrictive effects of calcitonin gene-related peptide, its presence in pulmonary neuroendocrine cells, even in small amounts, may be important in controlling pulmonary vaso- and/or bronchomotor tone. The presence of large numbers of calcitonin gene-related peptide immunoreactive cells in infants with bronchopulmonary dysplasia suggests that calcitonin gene-related peptide may be one further agent contributing to the pulmonary pathophysiology seen in this disease.     

Granular cell tumors: evidence for heterogeneous tumor cell differentiation

Eighteen granular cell tumors from various sites were examined with antisera directed against protein S-100, neuron specific enolase (NSE), alpha-1-antichymotrypsin, and alpha-1-antitrypsin, glial fibrillary acidic protein (GFAP), lysozyme, factor VIII-related antigen, myoglobin and vimentin, as well as with a monoclonal antibody (lu-5) directed against a panepithelial marker. The immunocytochemical reaction pattern of the tumors was heterogeneous. The brain and pituitary tumors and one thyroid tumor reacted for alpha-1-antichymotrypsin and alpha-1-antitrypsin, but not for S-100 protein and NSE. However, tumors from other sites showed immunoreactions for S-100 protein and NSE and some also for vimentin. Reactions for alpha-1-antichymotrypsin and alpha-1-antitrypsin were not observed. All other reactions were similarly negative. We conclude that the morphologically homogeneous group of granular cell tumors is biologically heterogeneous.