High activity of mitochondrial glycerol phosphate dehydrogenase in insulinomas and carcinoid and other tumors of the amine precursor uptake decarboxylation system. (1/22)

The activity of the mitochondrial glycerol phosphate dehydrogenase (EC 1.1.99.5), the enzyme unique to the glycerol phosphate hydrogen shuttle, was measured in normal human tissues and tumors and compared with the activity of succinate dehydrogenase, another enzyme that transfers electrons to ubiquinone at site II of the electron transport chain. Six of 7 insulinomas and 10 of 12 carcinoid tumors showed high glycerol phosphate dehydrogenase activity. The activity was also increased in 3 of 4 gastrinomas, 2 paraganglionomas, 1 of 4 thyroid nodules, and 1 parathyroid tumor. These tissues belong to the amine precursor uptake decarboxylation system. The activity of glycerol phosphate dehydrogenase was generally unremarkable in non-amine precursor uptake decarboxylation system tumors and in normal tissues studied. However, 1 of 2 breast carcinomas, 1 submandibular tumor, and 2 of 3 melanomas were enriched in glycerol phosphate dehydrogenase activity. In general, succinate dehydrogenase activity exceeded that of glycerol phosphate dehydrogenase in all tissues except some of the tissues in which glycerol phosphate dehydrogenase activity was high. Normal tissues, such as the pancreatic beta-cell, which aerobically metabolize glucose rapidly utilize the glycerol phosphate shuttle to oxidize the large amount of NADH formed from glucose metabolism in the cytosol. Whether this is the reason for the enriched activity of the glycerol phosphate dehydrogenase in certain amine precursor uptake decarboxylation system tumors is unknown.  (+info)

A survey of endocrine cells in the pancreas of the echidna (Tachyglossus aculeatus) with special reference to pancreatic motilin cells. (2/22)

Pancreatic endocrine cells were examined in a primitive egg-laying mammal, the echidna, using immunohistochemistry. Immunoreactive endocrine cells were observed using antisera to insulin, glucagon, somatostatin, avian pancreatic polypeptide and bovine pancreatic polypeptide. In addition, motilin-immunoreactive cells were identified in both the endocrine and exocrine pancreas of pouch-young and adult echidnas using three types of motilin antisera. Since the motilin-immunoreactive cells did not cross-react with any other pancreatic hormones tested, they are identified as an independent endocrine cell type.  (+info)

Production of calcitonin, adrenocorticotropic hormone, and beta-melanocyte-stimulating hormone in tumors derived from amine precursor uptake and decarboxylation cells. (3/22)

The tumor production of human calcitonin (CT) was examined by radioimmunoassay, and it was found that 50 of 85 (59%) tumor tissues collected at random contained immunoreactive CT. These tumors were grouped as to whether they were derived from the amine precursor uptake and decarboxylation (APUD) series. The group that was derived from APUD cells showed appreciable amounts of CT in 30 of 31 (97%) of these tumors or in 20 of 21 (95%) when the medullary carcinomas of the thyroid were excluded. However, of the non-APUD group of tumors only 20 of 54 (37%) were found to contain CT, so that the difference between these two groups was highly significant (p less than 0.001). Of the tumors with ectopic adrenocorticotropic hormone-melanocyte-stimulating hormone production, 12 of 14 were shown to contain CT. These data indicate that CT is a common product of the APUD tumors and that tumor production of CT is often associated with that of adrenocorticotropic hormone and beta-melanocyte-stimulating hormone.  (+info)

Sequential morphologic alterations in the bronchial epithelium of Syrian golden hamsters during N-nitrosomorpholine-induced pulmonary tumorigenesis. (4/22)

N-nitrosomorpholine (NM)-induced pulmonary carcinogenesis was examined by light and electron microscopy in a 20-week serial sacrifice study using Syrian golden hamsters. First to be observed were a proliferation of endocrine APUD cells and a formation of lamellated inclusion bodies in the cytoplasm of Clara cells. After continued NM treatment, APUD cells underwent squamous metaplasia and Clara cells invaded the pulmonary tissues adjacent to the bronchi. Lung tumors consisted of cells possessing numerous lamellated inclusion bodies in their cytoplasm and a few squamous metaplastic and APUD cells. The observed pathologic alterations closely resembled those found after treatment with N-diethylnitrosamine (DEN) and N-dibutylnitrosamine (DBN) but were completely different from the cellular reactions induced by polycyclic aromatic hydrocarbons. It is concluded that the observed alterations of APUD cells and Clara cells are specific to nitrosamines.  (+info)

Quantitative characteristics of the Feyrter (APUD) cells of the neonatal rabbit lung in normoxia and chronic hypoxia. (5/22)

Our studies show that the apparent number of Feyrter cells in the lung declines during the neonatal period in normoxic rabbits, and that in hypoxic animals a uniformly and significantly lower number of cells occurs as compared with the normoxic rabbits. There is some indication of degranulation of cells in the hypoxic groups. It is suggested that environmental and/or physiological factors associated with the start of extrauterine life, or lung development, may affect the apparent number and probable level of activity of these cells. These changes seem to be enhanced by hypoxia. Mast cells are scarce, and Feyrter cells are relatively more numerous along the airways. These cell types could possibly represent storage sites for 5-hydroxytryptamine, as suggested also by other investigators. Intraepithelial nerve fibres in bronchi and bronchioles were found but they were not limited to innervations of Feyrter cells or related cell bodies.  (+info)

Endocrine-like cells in the terminal bronchioles and saccules of human fetal lung: an ultrastructural study. (6/22)

An ultrastructural study of Kulschitsky cells was made on lung tissue from five human fetuses of gestational ages between 18 and 25 weeks. The cells were found to occur with relative frequency throughout the bronchi and bronchioles, as well as in the developing saccules. This report describes in detail the cells of the terminal bronchioles and saccules, where their long cytoplasmic processes weave through the epithelium and come into contact with intercellular spaces and the lumen. The cytoplasmic organelles have an orderly arrangement comparable to secreting cells. Dense core vesicles characterise the cytoplasm but clear vesicles and some with less dense, diffuse cores are also present, and may be seen outside the plasma membrane and in the interstitial spaces. The K-cells are usually colsely associated with capillaries or smooth muscle cells across the basement membrane. In addition, the rare occurrence of a small unmyelinated nerve fibre in the vicinity of a K-cell in a terminal bronchiole raises the possibility that the cells fulfill a type of 'mini receptor' role in addition to their probable vasoactive one. Evidence is given that K-cells divide in human fetal lung.  (+info)

Neuroendocrine differentiation antigen on human lung carcinoma and Kulchitski cells. (7/22)

In the normal lung, a subset of cells with a histological appearance consistent with that of Kulchitski cells are the only lung cells reacting with a monoclonal antibody (MOC-1) raised against a human small cell lung carcinoma-derived cell line. Outside the lung, a subset of normal endocrine cells (in the adrenal, thyroid, ovary, and pancreas) as well as neural cells (brain and peripheral Schwann cells) also express the antigen detected by MOC-1 (named MOC-1-related antigen). Some of these positively reacting cells are ectodermally derived, whereas others are of proven endodermal origin, indicating that the MOC-1-related antigen is not a cell lineage-specific antigen. Instead, the common expression of the antigen by cells with a neural, endocrine, or neuroendocrine function suggests that the antigen related to a neuroendocrine differentiation state of these cells. The presence of the MOC-1-related antigen on several non-lung tumors mostly paralleled its normal tissue distribution, indicating that the antigen is generally retained upon malignant transformation. In lung carcinoma, the antigen proves to be present on almost all small cell carcinomas tested. In addition, adenocarcinoma and mixed adenosquamous carcinoma could also express the antigen, whereas pure squamous cell carcinoma generally did not. This finding will be discussed in relation to a proposed "common stem cell" histogenesis of lung carcinoma.  (+info)

Pulmonary endocrine cells immunoreactive for calcitonin in the lungs of fetal and neonatal rats. (8/22)

Previous studies have shown that the size of the population of bronchopulmonary endocrine (Feyrter) cells appears to be greatest in fetal and neonatal life. This has led to the logical assumption that these cells are important during this period and undergo a subsequent decline in number thereafter. In this study endocrine cells containing calcitonin or a closely related cross reacting peptide have been demonstrated in the lungs of fetal and neonatal rats by immunoenzyme histochemistry. They appear first about three days before birth and their number, expressed as immunoreactive cells per cm2 of histological section, remains relatively constant for up to three weeks after birth. It has been shown previously in this department that endocrine cells immunoreactive for calcitonin are present in the lungs of the normal adult rat. Their number in these adult animals is closely similar to the numbers of cells in the lungs of the developing animals of the present study. It is suggested that, at least in the rat, bronchopulmonary endocrine cells immunoreactive for calcitonin have a role that is not confined merely to the period of transition from fetal to neonatal life.  (+info)