Cell types in the adenohypophysis of the Japanese quail and effects of injection of luteinizing hormone-releasing hormone

The cells of the adenohypophysis of the Japanese quail were studied by both light and electron microscopy after exposure to long photoperiods or injection of lutenizing hormone-releasing hormone (LRH). Six cell types were identified in the adenohypophysis by examining alternate thick and thin sections by light and electron microscopy. In the cephalic lobe, there are four types of glandular cells. They are the prolactin cells, ACTH cells, TSH cells, and gonadotropic cells (FSH?). In the caudal lobe, there are two types of cells, STH cells and gonadotropic cells (LH?). After exposure to long daily photoperiods, gonadotropic cells in both lobes were strongly activated. They became larger and accumulated many granules. ACTH cells became vacuolated; granules were sparse. Synthetic LRH injection (10 mug/0.2 ml/day) for 10 days to the non-photostimulated quail stimulated certain numbers of the gonadotropic cells in the both lobes, although the response of the cells was less than that induced by photostimulation. No response was seen in the other cell types.     

Corrective note about R* cells of the digestive gland of the shore crab Carcinus maenas

In a previous paper, we described and discussed the possible functions of calcospherite-rich cells (R^* cells) in the digestive gland of the shore crab, Carcinus maenas. We recently realised that electron micrographs in this publication presented neither typical R^* cells nor their calcium phosphate granules. Indeed, our pictures showed spermatophores (filled with typical spermatozoa) that had contamined hepatopancreatic cell suspensions. As the present study indicates, this contamination is difficult to detect by optical microscopy because unstained R^* cells closely resemble spermatophores. However, morphological differences between these cell types appear clearly when observed by electron microscopy. The present paper describes a comparative study of cell populations isolated from female digestive glands; it validates our previous results obtained with male hepatopancreas and suggests a low containation of those male cell fractions by spermatophores.     

Major metabolic pathways and hormone production in unstimulated monolayer cultures of the rat anterior pituitary

In cell cultures derived from anterior pituitary glands of rats, enzyme activities of cell homogenates and hormone (GH, PRL, LH, and FSH) content of the culture media were measured. Sex differences in enzyme activities representing major metabolic pathways (citrate cycles, pentose cycles, and glycolysis) were demonstrated both in freshly dispersed cells and in 8-day-old cultures; in cultures of both sexes enzyme activities increased during cultivation. In cultures derived from female rats, cell protein doubled by the 12th day and remained constant for up to the 24th day in culture, whereas enzyme activities showed changes suggesting that cell metabolism shifted to anaerobic glycolysis during cultivation. In the culture media the presence of four pituitary hormones was demonstrated for as long as 3 weeks of cultivation with variable secretion dynamics; the release of gonadotropic hormones diminished gradually whereas that of GH remained constant and PRL levels increased with time. These results indicate that under strictly defined culture conditions pituitary cells may function in spite of profound metabolic changes.     

Major metabolic pathways and hormone production in unstimulated monolayer cultures of the rat anterior pituitary

Summary In cell cultures derived from anterior pituitary glands of rats, enzyme activities of cell homogenates and hormone (GH, PRL, LH, and FSH) content of the culture media were measured. Sex differences in enzyme activities representing major metabolic pathways (citrate cycles, pentose cycles, and glycolysis) were demonstrated both in freshly dispersed cells and in 8-day-old cultures; in cultures of both sexes enzyme activities increased during cultivation. In cultures derived from female rats, cell protein doubled by the 12th day and remained constant for up to the 24th day in culture, whereas enzyme activities showed changes suggesting that cell metabolism shifted to anaerobic glycolysis during cultivation. In the culture media the presence of four pituitary hormones was demonstrated for as long as 3 weeks of cultivation with variable secretion dynamics; the release of gonadotropic hormones diminished gradually whereas that of GH remained constant and PRL levels increased with time. These results indicate that under strictly defined culture conditions pituitary cells may function in spite of profound metabolic changes.     

The relation between pituitary gland and thyroid growth during the lifespan of the annual fish Cynolebias whitei and Nothobranchius korthausae: gonadotropic and thyrotropic cells

Summary In the annual cyprinodont Cynolebias whitei the cell types responsible for the increase of pituitary growth at the onset of maturation and for pituitary hyperplasia in old specimens were identified as gonadotropic cells and thyrotropic cells, respectively. The gonadotropic cells showed a high affinity to anti-carp -GTH serum, both at light- and electron-microscopical levels. The allometric relation of total gonadotropic cell volume to body length, determined for fish from six weeks up to six months of age, showed no inflections. Therefore pituitary growth in maturing fish may be partly a result of proliferation of gonadotropes, although gonadotropic cells do not contribute to pituitary hyperplasia in old fish. Thyrotropic cells showed a weak affinity to anti-carp -GTH serum at light-microscopical level. Under the electron microscope thyrotropic cells displayed signs of activation in maturing fish and signs of proliferation in old fish. The allometric relation of thyroid gland volume to body length paralleled that of pituitary volume to body length. Histologically the thyroid gland showed signs of inactivity in adult fish and of hyperplasia in old fish. The possibility, that gonadal maturation, pituitary thyrotropic activity, and growth of the thyroid in maturing fish are related through the inhibitory action of gonadal steroids on thyroid hormone release, is discussed. Pituitary hyperplasia in old fish is the result of proliferation of thyrotropic cells. Similar hyperplasia of pituiary and thyroid glands was observed in old Nothobranchius korthausae.     

Ultrastructure of the pars distalis of the lizard Anolis carolinensis with special reference to the identification of the gonadotropic cell

Summary Five categories of granulated cells were distinguished by their ultrastructural features, and quantitative analyses were made of the pars distalis cells in normal and castrated lizards. The gonadotropin-producing cell was identified on the basis of its uniform distribution in the gland as well as from cytological changes resulting from castration. The secretory granules of the gonadotropic cell vary in size (100–500 m) and density, and lipid bodies are commonly present. Following castration, the endoplasmic reticulum proliferates, forming many small, rough-surfaced, dilated cisternae which do not coalesce greatly as in other vertebrate species. Degranulation is accompanied by hypertrophy and hyperplasia of the mitochondria and by the appearance in the cytoplasm of conspicuous clusters of microfilaments. The designated gonadotropic cell was the only class of secretory cell showing consistent changes following three weeks of castration.In addition to the uniformly distributed gonadotrope cell, two secretory cells occur mainly in the rostral half of the gland, and two in the caudal half. Tentative identification of the cell types is discussed in the light of available information on the localization of the hormones in the pars distalis of this species.Grateful recognition is given to the Electron Microscope Laboratory of the University of California, Berkeley, for use of their facilities, and to Emily Reid for her assistance with the illustrations.Member of Consejo Nacional de Investigaciones Cientificas y Técnicas.     

Ultrastructural and ultracytochemical studies of the gill epithelium in the larvae of Salamandra salamandra (Amphibia,Urodela)

Summary The morphology of Salamandra salamandra (Linné, 1758) larva gills is described by scanning and transmission electron microscopy. Three main cell types comprising the surface of the gill epithelium are described: (a) pavement cell, (b) ciliary cell and (c) mitochondria-rich cell (MRC). Two subtypes of MRC were distinguished by their ultrastructural characteristics: a fibrillar cell and a tubulovesicular cell. K^ü-dependent-nitrophenyl-phosphatase (K-NPPase) activity, indicative of Na^ü-K^ü-ATPase activity was confined to the basolateral membranes of the pavement cells. MRC were devoid of such activity. Possible relationships between structure and function of the different cell types are discussed.     

The Pituitary Gland of the Roach Leuciscus rutilus

Three endocrine cell types were recognized in the proximal pars distalis (PPD) of the roach, Leuciscus rutilus, by electron microscopy. Two of these cell types are basophilic and assumed to be gonadotropic. The third cell type is acidophilic and its similarity to somatotropic (STH) cells is evident. Green fluorescent cells corresponding to cells with dense core vesicles of about 85 nm are scattered between the PPD and the proximal neurohypophysis (PNH). Their possible content of a catecholamine was demonstrated with microspectrofluorometric analyses. Four axon types with granules 65, 81, 110 and 137 nm in average diameter terminate at the basement membrane. Only fibers with granules of 81 nm enter the PPD to make synapses with the STH cells. Extensions of the basement membrane are continuous with the perivascular space and penetrate the endocrine tissue. It is postulated that axon terminals on the basement membrane are functionally equivalent to synaptic contacts on the endocrine cells. Axon type 4 has granules which in sizes correspond to those of cells in lateral and ventrolateral parts of the nucleus lateralis tuberis (NLT). A similar correlation is possible between axon type 3 and other cells in the NLT. This is in accordance with earlier conclusions of a regulation of the gonadotropic cells from the lateral (posterior) parts of the NLT.     

Isolation of Cytoplasmic Pituitary Granules with Gonadotropic Activity

A fraction isolated from the anterior pituitary glands of rats castrate for 8 weeks contained essentially a single cytoplasmic constituent with which the major portion of the gonadotropic hormone activity was associated. The glands were homogenized in an 0.25 M sucrose + 7.3 per cent polyvinylpyrrolidone (PVP) solution and fractionated by differential centrifugation to give a heterogeneous small granule fraction which contained almost all the gonadotropic hormone activity. The active supernatant containing this small granule fraction was separated into layers by isopycnic gradient centrifugation on a continuous 6 to 45 per cent sucrose + 17.5 per cent "diodrast" + 5 x 10^-4 M "versene" gradient at 100,000 g for 2 hours. Three layers were obtained and the pellet from the active bottom layer was sectioned, examined with the electron microscope, and found to contain 200 mµ granules, mitochondria, ergastoplasm, and other cellular debris. This layer was fractionated further by isopycnic and differential centrifugation to obtain a pellet which contained the major portion of the gonadotropic hormone activity. Because of the heterogeneity of this fraction, due to the contamination of the 200 mµ granules with mitochondria and other cellular debris, the active layer and the resuspended active pellet, obtained by centrifuging this layer first at 17,000 g then diluting the supernatant and centrifuging at 30,000 g for 1 hour, were filtered through Millipore HA paper with a pore size of 0.45 µ. The cytoplasmic material containing the gonadotropic hormone activity passed through the filter paper and this activity was recovered in the pellets obtained by centrifuging at 100,000 g for 1 hour. These active pellets consisted almost entirely of 200 mµ granules with a minimum amount of contamination, and they contained the major portion of the gonadotropic hormone activity with practically none remaining in the supernatant fraction. These results are discussed in view of their importance to the cytology of the pituitary gland.     

The ultrastructure and histology of the perinotal epidermis and defensive glands of two species of Onchidella (Gastropoda: Pulmonata)

Histology and electron microscopy were used to describe and compare the structure of the perinotal epidermis and defensive glands of two species of shell-less marine Systellommatophora, Onchidella capensis and Onchidella hildae (Onchidiidae). The notum of both species is composed of a layer of epithelial and goblet cells covered by a multi-layered cuticle. Large perinotal multi-cellular glands, that produce thick white sticky mucus when irritated, are located within the sub-epidermal tissue. The glands are composed of several types of large secretory cell filled with products that stain for acidic, sulphated and neutral mucins, and some irregularly shaped support cells that surround a central lumen. The products of the secretory cells are produced by organelles that are basal in position. The entire gland is surrounded by a well-developed capsule of smooth muscle and collagen, and in addition smooth muscle surrounds the cells within the glands. Based on the size of the gland cells, their staining properties, and the appearance of their stored secretions at the transmission electron microscope level, five different types of secretory cells were identified in O. capensis and four in O. hildae. The products of these cells, which are released by holocrine secretion, presumably mix in the lumen of the duct as they are forced out by contraction of the smooth muscle. The structural similarity of these glands to those of siphonariids, suggest that they have a common ancestry.     

The goldfish pituitary

Summary In the goldfish, Carassius auratus, morphological and functional aspects of the pituitary gland were studied at the ultrastructural level and six cell types could be distinguished in the pars distalis. Acidophilic cells of the rostral pars distalis were identified as prolactin cells, the chromophobic cells of the rostral pars distalis as ACTH cells, the non-globular basophilic cells of the rostral and the proximal pars distalis as TSH cells, the globular basophils of the proximal pars distalis as gonadotropic cells and the acidophils of the proximal pars distalis as somatotrophs.Besides some of the well established criteria of morphological and functional identification of different cell types, two new approaches have been used in the present study. One was to express the electron density of secretory granules objectively by means of a photometric method. It was found that both types of acidophilic cells which produce the proteohormones prolactin and somatotropin respectively, had granules with the highest electron densities. The basophilic cells producing the glycoproteins gonadotropin and TSH respectively, possessed granules of intermediate electron density whereas the chromophobic cells storing the peptide hormone ACTH had granules of lowest densities. The second new approach was the administration of the synthetic mammalian releasing hormones LH-RP and TRF, which helped in identifying gonadotropic and thyrotropic cells respectively. In the goldfish there is evidence for the presence of only one type of gonadotropic cell.Supported by a grant of the Science Research Council of Great Britain to Professor Sir Francis Knowles, F.R.S. The electron microscope used was provided by the Medical Research Council of Great Britain. The integrating photometer IPM2 was kindly on loan from Messrs. Carl Zeiss, Oberkochen, Germany. For technical advice we are greatly indebted to Mr. P. K. Kaul, B. E., M.I. Struct. E., C. Eng.     

Ultrastructural studies on erythropoiesis in the avian thymus

Summary Thymus lobes from three species of birds, Quelea quelea, Passer domesticus and Sturnus vulgaris, have been examined ultrastructurally. The component cell types are compared with their counterparts in mammalian thymus glands, and found to be similar. Greater differences exist between small, intermediate and enlarged lobes of one species than exist between species. Developing erythroid cells are present in most enlarging and some enlarged glands. They appear to be developing at the expense of lymphoid cells in some birds. The origin of these cells is discussed. Cells that are possible candidates for the production of some thymic hormones are also described.Formerly: Houghton Poultry Research Station, Houghton, Huntingdon, Cambs     

Ultrastructure and cytochemistry of the gastric mucosa of a reptile,Tiliqua scincoides

Summary The gastric mucosa of a reptile, the lizard Tiliqua scincoides, has been examined by light and electron microscopy. The gastric pits lead into glands that are extensively coiled in the proximal stomach but become progressively shorter and straighter in the distal stomach. The following epithelial cell types have been identified: (i) Surface mucous cells (SMC) line the entire lumenal surface as well as the pits. They contain mucus granules that stain with periodic acid-Schiff and, like the granules of mammalian SMC, commonly contain an electron dense core that appears not to be mucus (periodic acid-chromic acid-silver methenamine nonreactive). (ii) Glandular mucous cells are present in glands throughout the mucosa. They are probably homologous with the mucous neck and antral gland cells of mammals; like SMC their mucus granules contain nonglycoprotein cores. (iii) Oxynticopeptic cells (OPC) are the predominant cell type in the proximal glands but become infrequent distally. Their fine structure resembles that of OPC in other nonmammalian vertebrates, with features like those of both parietal cells and zymogen cells of mammals, (iv) Endocrine cells of three different types have been identified. Two of these show close similarities to the EC and ECL cells of mammals.The authors thank Mrs. D. Flavell for technical assistance. This study was supported by a grant from the Clive and Vera Ramaciotti Foundations     

Immunocytology and Innervation of the Gonadotropic Cells in the Teleost Fish Rutilus rutilus

Abstract The double immunofluorescent method indicates that two types of gonadotropes occur in the proximal pars distalis of the teleost fish Rutilus rutilus. With rabbit anti-carp GTH as the first antibody the two cell types cross-react whereas after rabbit anti-salmon GTH as the first antibody only the so-called globular cell, known to produce gonadotropin in teleosts, cross-reacts. The cytological differences between the two assumed gonadotropic cells are reviewed. The pseudoisocyanine technique gave a selective fluorescent picture of the assumed gonadotropes. Fine structural analysis shows that the gonadotropic cells close to the neurohypophysis are innervated by one type of fiber in contrast to most of the gonadotropic cells, which are not innervated. In the latter case the neuroendocrine information reaches the gonadotropic cells by a median eminence system in which the intervascular channels in the proximal pars distalis are the last parts.     

Immunocytochemical localization of Na+/K+-ATPase and V-H+-ATPase in the salivary glands of the cockroach,Periplaneta americana

The acinous salivary glands of the cockroach (Periplaneta americana) consist of four morphologically different cell types with different functions: the peripheral cells are thought to produce the fluid component of the primary saliva, the central cells secrete the proteinaceous components, the inner acinar duct cells stabilize the acini and secrete a cuticular, intima, whereas the distal duct cells modify the primary saliva via the transport of water and electrolytes. Because there is no direct information available on the distribution of ion transporting enzymes in the salivary glands, we have mapped the distribution of two key transport enzymes, the Na⁺/K⁺-ATPase (sodium pump) and a vacuolar-type H⁺-ATPase, by immunocytochemical techniques. In the peripheral cells, the Na⁺/K⁺-ATPase is localized to the highly infolded apical membrane surface. The distal duct cells show large numbers of sodium pumps localized to the basolateral part of their plasma membrane, whereas their highly folded apical membranes have a vacuolar-type H⁺-ATPase. Our immunocytochemical data are supported by conventional electron microscopy, which shows electrondense 10-nm particles (portasomes) on the cytoplasmic surface of the infoldings of the apical membranes of the distal duct cells. The apically localized Na⁺/K⁺-ATPase in the peripheral cells is probably directly involved in the formation of the Na⁺-rich primary saliva. The latter is modified by the distal duct cells by transport mechanisms energized by the proton motive force of the apically localized V-H⁺-ATPase.     

两栖类消化道嗜银细胞和5-羟色胺细胞的研究进展

嗜银细胞属于内分泌细胞类,是消化道所含各类内分泌细胞的总称,5-羟色胺是其中含量和分布范围较广的一种胃肠激素。本文总结了两栖动物消化道嗜银细胞和5-羟色胺细胞的形态学特征、分布位置和分布密度规律,概述了冬眠、禁食和不同生活史阶段与两种细胞分布密度的关系。     

The Endothelin/Sarafotoxin‐Induced Increase of the Proliferation of Undifferentiated and DMSO‐Differentiated GEM‐81 Goldfish Erythrophoroma Cells is Mediated by ETB Receptors

Endothelins (ETs) and sarafotoxins (SRTXs) have been reported to exert ET_B‐mediated effects on vertebrate pigment cells. GEM‐81 cell line, a red pigment cell‐derived cutaneous tumor of the teleost Carassius auratus, expresses ET_B receptors and can be differentiated with 1.5% DMSO treatment, thus constituting an useful model to investigate ET and SRTX effects on cultured fish pigment cells. Our aim was to characterize the pharmacology and biological effects mediated by ET receptors in DMSO‐differentiated and undifferentiated cells. ET subtype receptors and their respective Ki values in both cell types were determined by competitive binding assays using ¹²⁵I ET‐1 and BQ‐485 (an ET_A antagonist) or BQ‐788 (an ET_B antagonist). BQ‐788, but not BQ‐485, significantly reduced ¹²⁵I‐ET‐1 binding in both cell types, with similar low (Ki > nM) affinities. To determine the proliferation effects of ETs/SRTXs, cells were treated for 72 h with the hormones, and counted in a hemocytometer. The proliferation assays were repeated for SRTX S6c in the presence or absence of BQ‐788. The results demonstrated that, with the exception of ET‐1 (biphasic effect) and ET‐3 (no significant effect) in undifferentiated GEM‐81 cells, all the tested hormones induced increases in the proliferation of both types of cells. The hormones were equipotent in DMSO‐differentiated cells, which exhibited increased sensitivity to ETs, but not to SRTXs, as compared with undifferentiated cells. The BQ‐788 antagonistic effect was also exerted on the proliferation responses to SRTX S6c. These results corroborate the long and important evolutionary history of the ET/SRTX receptor system in vertebrate pigment cells.     

Isolation of mesophyll and secretory cell protoplasts of the halophyte Ceratostigma plumbaginoides (L.): a comparison of ATPase concentration and activity

Summary A method is described for isolating mesophyll protoplasts from leaves and secretory cell protoplasts from salt glands of the facultative halophyte, Ceratostigma plumbaginoides (L.). Rates of ATP hydrolysis in both cell types were determined, and levels in secretory cell protoplast preparations were fourfold higher than those in mesophyll protoplast preparations, based on total protein. The rate of ATP hydrolysis was sensitive to azide and vanadate, and stimulated by Triton-X-100. Additionally, immunoblot procedures using an antibody to the plasma membrane H⁺/ATPase was used to compare ATPase levels of the mesophyll and secretory cell protoplasts. Results indicate that secretory cells have a higher concentration of H⁺/ATPase than mesophyll cells, consistent with their putative function in salt glands.Abbreviations ATP adenosine triphosphate - BSA bovine serum albumin - DIDS diisothiocyano-2,2'-disulfonic acid stilbene - DNP dinitrophenol - DTT dithiothreitol - FITC fluorescein isothiocyanate - NAD⁺/NADH nicotinamide adenine dinucleotide - SDS sodium dodecylsulfate     

DISTINCTIVE LOCALIZATION OF GROUP 3 LATE EMBRYOGENESIS ABUNDANT SYNTHESIZING CELLS DURING BRINE SHRIMP DEVELOPMENT

Despite numerous studies on late embryogenesis abundant (LEA) proteins, their functions, roles, and localizations during developmental stages in arthropods remain unknown. LEA proteins protect crucial proteins against osmotic stress during the development and growth of various organisms. Thus, in this study, fluorescence in situ hybridization was used to determine the crucial regions protected against osmotic stress as well as the distinctive localization of group 3 (G3) LEA⁺ cells during brine shrimp development. Several cell types were found to synthesize G3 LEA RNA, including neurons, muscular cells, APH‐1⁺ cells, and renal cells. The G3 LEA⁺ neuronal cell bodies outside of the mushroom body projected their axonal bundles to the central body, but those inside the mushroom body projected their axonal bundles toward the deutocerebrum without innervating the central body. The cell bodies inside the mushroom body received axons of the G3 LEA⁺ sensory cells at the medial ventral cup of the nauplius eye. Several glands were found to synthesize G3 LEA RNA during the nauplius stages of brine shrimp, including the sinus, antennal I and II, salt, and three ectodermal glands. This study provides the first demonstration of the formation of G3 LEA⁺ sinus glands at the emergence stages of brine shrimp. These results suggest that G3 LEA protein is synthesized in several cell types. In particular, specific glands play crucial roles during the emergence and nauplius stages of brine shrimp.