An immunocytochemical study of the pituitary gland of the white seabream (Diplodus sargus)

The adenohypophysis of the white seabream (Diplodus sargus) was studied using histochemical and immunocytochemical techniques. The adenohypophysis was composed of rostral pars distalis, proximal pars distalis and pars intermedia. Prolactin (anti-chum salmon prolactin positive) and adrenocorticotropic (anti-human ACTH positive) cells were found in the rostral pars distalis. Prolactin cells were organized into follicles, while ACTH cells were arranged in cords around neurohypophyseal tissue branches that penetrated the rostral pars distalis. In the proximal pars distalis, somatotropic (anti-chum salmon and anti-gilthead seabream growth hormone positive), gonadotropic (anti-chum salmon -gonadotrophin II and anti-carp -gonadotrophin II positive, but anti-chum salmon -gonadotrophin I negative) and thyrotropic (anti-human -thyrotropin positive) cells were observed. Growth hormone cells were restricted to the dorsal and ventral part of the proximal pars distalis. They were clustered or surrounded the neurohypophyseal branches. Only one type of gonadotrophin cell was identified and they were clustered or isolated in the proximal pars distalis. Scattered groups of thyrotropin cells were located throughout the proximal pars distalis. In the pars intermedia somatolactin (anti-chum salmon and anti-gilthead seabream somatolactin positive) and melanotropic (anti--melanotropic hormone positive) cells were localized. In addition, gonadotrophin cells surrounded the pars intermedia or distributed evenly between somatolactin and melanotropic hormone cells. Somatolactin cells were periodic acid-Schiff negative and surrounded the neurohypophyseal branches intermingled with melanotropic cells. These cells were also immunoreactive to anti-human ACTH antiserum.     

Changes in the pituitary of the migrating European eel during its journey from rivers to the sea

Summary The present studies demonstrate that, as migrating European silver eels enter the sea, important changes occur in the pars distalis of the pituitary. A decrease of Type A neurosecretory material in all nerve tracts penetrating the pars distalis was observed, as was an increased activity of Type B neurosecretion in the tracts of the proximal pars distalis.In the proximal pars distalis, gonadotropic cells show striking changes, and in the rostral pars distalis thyrotropic and prolactin cells. It is discussed whether these changes are related to migration to breeding grounds or to changes in the environment.Dedicated to Dr. Berta Scharrer on her 60th birthday.     

Ultrastructure of the pituitary gland (pars distalis) in sockeye salmon (Oncorhynchus nerka) during gonad maturation

Summary The fine structure of the various hormone-producing cell types (with the exclusion of the prolactin cells) in the pituitary gland (pars distalis) of migratory sockeye salmon is described. All fish were in an advanced stage of sexual maturation. In the proximal pars distalis five cell types were distinguished: growth hormone cells, ACTH cells, gonadotrops, vesicular cells, and chromophobe cells. Gonadotrops were also found throughout the rostral pars distalis. A conspicuous feature of the gonadotrops was the presence of two kinds of secretory inclusions: small electron-dense granules (200–375 m) and large, relatively electron-translucent globules (400–2 000 m). The large vesicular cells, so called because of their conspicuous vesicular endoplasmic reticulum, were numerous and often appeared to contain some small granules. It is argued that they may represent a second type of gonadotropic cell, which, in earlier stages of gonad development, contains many granules but becomes largely degranulated near the time of reproduction when the other gonadotrops (globular gonadotrops) abound. The chromophobes, which were smaller and far less abundant than the vesicular cells, also appeared to contain small granules (120–280 m). They are probably thyrotrops.The assistance of Mr. S. Killick, of the International Pacific Salmon Fisheries Commission, who helped in the collection of salmon, is gratefully acknowledged.     

Immunocytochemical localization of POMC-derived peptides (adrenocorticotropic hormone, α-melanocyte-stimulating hormone and β-endorphin) in the pituitary,brain and olfactory epithelium of the frog,Rana esculenta,during development

Developmental stages of Rana esculenta, starting with the posterior limb-bud stage (stage 26) up to a few days after metamorphosis, were examined immunohistochemically to localize cells and fibers producing some POMC-derived peptides, namely, -MSH, ACTH and -END. Anti ACTH and anti -MSH revealed a positive reaction in the pars intermedia during all stages of development included in this study, whereas no immunoreactivity in this pituitary zone was ever evidenced with anti -END. In the pars distalis strongly positive cells were seen with anti ACTH and anti -END, while anti -MSH yielded weakly positive cells. Interestingly, these peptides were colocalized in the same cells. Immunoreactivity for -MSH was no longer present in the pars distalis during metamorphic climax and postmetamorphosis. In the brain of premetamorphic tadpoles, belonging to stages 26 to 30, a few neurons in the posterior telencephalon showed a positive reaction only with anti -MSH,but from stage 31 (prometamorphosis) onwards, ACTH and -endorphin-like peptide producing cells, together with -MSH-immunoreactive cells, were seen in this region and in the anterior preoptic area and infundibulum. This situation persisted in the subsequent stages of development. Anti -MSH also revealed weakly positive cells in the olfactory epithelium in premetamorphic tadpoles; strong immunoreactivity with anti -MSH was seen in olfactory epithelium cells in animals during prometamorphosis, metamorphic climax and postmetamorphosis. The possible significance of these findings is briefly discussed.     

Identification of the LH and TSH-secreting cells in the pituitary gland of the rhesus monkey

Summary Pituitary glands from juvenile (pre-pubertal) and adult male and female rhesus monkeys were examined following immunocytochemical staining with antisera to the beta subunits of ovine luteinizing hormone (LH) and of human thyroid stimulating hormone (TSH). The LH antiserum reacts with a cell that is PAS-positive, occurs singly and is randomly distributed throughout the pars distalis. The diameter of these cells is approximately 11.5 m. They do not seem to vary in number in either juveniles (pre-pubertals) or adults, or in males or females. There appears to be fewer LH cells in the pituitary glands of pregnant and lactating females. In addition to staining cells in the pars distalis, the antiserum also reacts with a population of cells located in the pars tuberalis.The cells that stain with the anti-TSH serum are confined primarily to the pars distalis. They are approximately 15.8 m in diameter and are generally found in groups or clusters located in the anterior and medial regions of the gland. The TSH cells vary in number from one animal to another; however, this variability is unrelated to the age or the sex of the animals. No demonstrable changes occur in the number of TSH cells during pregnancy or lactation.Supported by NIH General Research Support Grant RR05654The author wishes to express appreciation to the Hormone Distribution Program of NIAMDD for the preparations of ovine FSH, TSH and human TSH, and to Drs. H. Papkoff for the ovine LH and LH, L. Reichert for the human FSH, J. Vaitukaitis for the anti-human TSH, and L.A. Sternberger for the PAP complex     

Ontogenesis of cells producing polypeptide hormones (ACTH,MSH, LPH,GH, Prolactin) in the fetal hypophysis of the rat: Influence of the hypothalamus

Summary The ontogenesis of cells containing polypeptide hormones (ACTH, MSH, LPH, GH and Prolactin) was investigated in the fetal rat hypophysis by immunohistochemistry using the peroxidase-antiperoxidase complex.Corticotrophs, melanotrophs and lipotropic cells were revealed earlier in the pars distalis than in the pars intermedia. In the pars distalis, cells producing LPH were found in the morning of day 15 of gestation using anti-- or anti--LPH sera, and in the afternoon using anti-- or -endorphin sera. Cells containing -MSH were observed from the afternoon of day 15. The cells stainable with the anti--MSH, anti--(17-39)ACTH and anti--(l-24)ACTH sera appeared on day 16. In the pars intermedia, the cells producing -MSH, MSH, - and -endorphin, and -LPH were observed in the morning of day 17, while cells containing ACTH were only revealed in the afternoon of the same day of gestation. Based on the treatment of serial paraffin sections with various antisera, it was clearly shown that MSH, ACTH, and LPH occur in the same cells located in the pars distalis as in the pars intermedia.The development of the corticotrophs, melanotrophs and lipotropic cells does not require the presence of the fetal hypothalamus or other central nervous structures. The pituitary glands of 21 day-old fetuses encephalectomized on day 16 showed as many reactive cells as those of the littermate controls.The somatotrophs were first revealed in the pars distalis in the afternoon of day 19. The cells producing prolactin were not observed before day 21 of gestation. On some cases GH and prolactin were found together in one cell. The cytodifferentiation of GH and prolactin cells is apparently not under hypothalamic control.     

Immunohistochemical localization of FSH and LH in the pars distalis of vervet (Cercopithecus aethiops) and babbon (Papio hamadryas) pituitaries

Summary Antisera against oLH¹, oLH and hFSH were used to localize gonadotropic cells in the pars distalis of Cercopithecus aethiops and Papio hamadryas. Three separate cell types were observed for FSH and LH: 85% of immunohistochemically identified gonadotropic cells reacted to all the various antisera; 10% reacted with the anti-LH antibody only; and 5% with the anti-hFSH antibody only. Comparisons between adjacent serial sections treated with various antisera, other than anti-gonadotropic hormones, demonstrated that the gonadotropic cells of these monkeys did not respond to these antisera.

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Résumé Des anticorps anti-LH ovine, anti-LH ovine et anti-FSH humaine ont été utilisés pour localiser les cellules gonadotropes dans la pars distalis de l'hypophyse des Singes Cercopithecus aethiops et Papio hamadryas. Trois catégories cellulaires distinctes, réagissant avec des anticorps anti-hormones gonadotropes, ont été observées. 85% des cellules immunoréactives identifiées en tant que cellules gonadotropes réagissent simultanément avec les différents anticorps mentionnés; 10% des cellules gonadotropes réagissent seulement avec l'anticorps anti-oLH et 5% de ces cellules seulement avec l'anticorps anti-hFSH. La comparaison avec des coupes adjacentes traitées par divers anticorps autres que les anticorps anti-gonadotropines prouve que les cellules gonadotropes de ces Singes ne réagissent jamais simultanément avec l'un ou l'autre de ces anticorps.

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Abbreviations used in this Article oLH ovine luteinizing hormone - hFSH human follicle stimulating hormone - ACTH corticotropin - GH growth hormone - LPH lipotropin - TSH thyrotropin     

Effect of 17β-estradiol on cells stained for FSHβ and/or LHβ in the dog pituitary gland

Summary The effect of long-term treatment (52 weeks) with high doses of 17-estradiol (1.28 mg/kg/week intramuscularly) on gonadotrophs was studied in the pituitary gland of the beagle bitch. For immunochemical staining the immunoperoxidase technique and antisera to the specific beta () subunits of FSH and LH were employed. For control purposes antisera to the following hormones were also used: bovine TSH, canine GH, canine PRL and porcine ACTH¹. In the pars distalis and pars tuberalis of control bitches, in addition to the cells which react solely with antisera to either LH or FSH, most cells were reactive to both antisera. The cells stained for FSH were less numerous than those shown to contain LH. TSH, PRL, GH and ACTH/MSH were localized in distinctly different cell types in the pars distalis of all control animals. In the treated bitches, almost complete regression of cells classically identified as gonadotrophs and stained for LH was observed. On the other hand, using the antiserum to FSH, selective immunochemical staining was localized in cells fitting the morphological characteristics of TSH cells. All these cells were also stained for TSH. However, a few cells were also shown to react solely with the antiserum to TSH. These cells, which seem to contain both TSH and FSH, were further clearly differentiated from PRL, GH and ACTH/MSH cells on the basis of their cytological features, intraglandular distribution and by immunochemical double staining. These observations support the concept that the one cell-one hormone theory may not necessarily apply to the glycoprotein hormones of the dog pituitary gland.Abbreviations of Hormones cited in this Paper ACTH Adrenocorticotropin - FSH Follicle Stimulating Hormone - GH Growth Hormone - LH Luteinizing Hormone - MSH Melanocyte Stimulating Hormone - PRL Prolactin - TSH Thyrotropin The authors are grateful to Mrs. K. Oertel for carrying out the experimental work on animals, to Mrs. B. Schilk and Miss U. Tüshaus for their excellent technical assistance, and to Dr. P. Günzel for his advice and encouragement     

Ultrastructure of STH cells of the pars distalis of castrated male mice after hepatectomy

Summary An electron microscopic study aimed at differentiation between castration gonadotrophs and posthepatectomy STH cells was performed on the pars distalis of the pituitary of castrated male mice, after partial hepatectomy. The ultrastructural features observed permit the distinction of both cell types. In the present experiments some remarkable ultrastructural changes, other than those described in a previous report, have been found in STH cells of hepatectomized mice with or without previous castration. Most of them contained masses of heterogeneous electron density, suggesting fusion of granules. These masses and some secretion granules were observed close to the plasma membrane, apparently in the process of discharging material into the pericapillary space. Granular extrusion was more frequent than normally. An increased number of lysosomes, probably related to the digestion of overproduced secretion material, was evident. The appearance of concentric lamellar formations might be related to an increase in cell movements. STH cells with severe cytoplasmic damage were also found, indicating an increased rate of cell loss.Work carried out with the financial assistance by a grant from the Comisión de Investigación Científica de la Universidad Nacional de La Plata. Thanks are due to the members of the Technical Staff of the Institute for their technical assistance.     

The use of BRM-activated killer cells in adoptive immunotherapy: A pilot study with nine advanced cancer patients

Adoptive immunotherapy using MHC-nonrestricted-lymphocytes, peripheral blood T cells and NK cells was devised. Peripheral blood mononuclear cells (3 x 107) were selected by immobilization to anti-CD3 monoclonal antibody for 4 days and cultured for 2 weeks in the presence of IL-2. Thereafter they were reactivated by 500 U/ml of IFN- and 1000 U/ml of IL-2 for 1 hour. Enhancement of NK and LAK activities was confirmed. Peripheral blood T cells proliferated in response to immobilized anti-CD3 antibody (3% to 30%). Approximately 6 x 109 BRM-activated killer (BAK) cells composed of CD56+ T cells and CD56+ NK cells, were dispensed to cancer patients via intravenous drip infusion. Nine patients were treated with BAK cells every 2 weeks or every month on an outpatient basis. During the course of adoptive immunotherapy, the crossed affinity immunoelectrophoresis (CAIE) pattern of serum immunosuppressive acidic protein (IAP) was analysed. Both the production and glycosylation pattern of IAP is changed in response to tumor enlargement and may therefore act as a marker of the disease progression. During the course of BAK therapy, the glycosylation IAP pattern of 6 patients changed from tumor (T) to normal (N). In addition, the performance status of all patients was maintained at 90–100% of the Karnofsky scale and any side effects including fever were not observed during treatments with BAK cells. Moreover, the overall quality of life (QOL) of the patients, scored at the Face scale was favorable. In addition, blood levels of activated T cells producing IFN- were assayed as an indication marker of BAK therapy. The normal range of IFN- producing T cells comprised 6.9 ± 0.9% of peripheral blood mononuclear cells (PBMC), according to a single cell FACScan analyses of PBMCs derived from normal individuals. IFN- producing T cells of Patients No. 8 and 9, who received extensive chemotherapy before initiation of BAK therapy, comprised only 0.2% and 2% of PBMC, respectively. These patients died 3 and 6 months after beginning BAK therapy. Peripheral blood T cells of Patients Nos. 1–7 proliferated in response to immobilized anti-CD3 antibody and the frequency of IFN- producing T cells in PBMC preparation of these patients were over 3% before initiation of BAK therapy. Since our data show a positive correlation between survival time and initial T cell counts, a low frequency of these cells may contraindicate BAK therapy.     

Comparative immunocytochemical demonstration of ACTH-, LH and FSH-containing cells in the pituitary of neonatal,immature and adult rats

Summary By means of immunocytochemistry, the development of ACTH-, LH- and FSH cells was examined in the anterior pituitary of 5-day-old neonatal, 15-day-old immature and adult rats. ACTH-positive cells are angular and the periphery of these cells is strongly reactive with anti-ACTH serum. In contrast, LH- and FSH-immunopositive cells are ovoid elements, ranging in cell size and intensity of staining. Angular cells, in which only the cell periphery reacted with anti-LH serum, were observed in neonatal and immature rats; however, these cells were not stained with either anti-FSH serum or anti-ACTH serum. Observation of serial semithin sections revealed that ACTH-immunopositive cells do not react with either anti-LH or anti-FSH serum. Finally, it was observed that ACTH cells and LH cells are both functionally differentiated already in 5-day-old neonatal rats.     

Ganglioside-cholera toxin interactions: a binding and lipid monolayer study

Summary On t.l.c. plates ¹²⁵I-cholera toxin binds to a disialoganglioside tentatively identified as GD_lb with about 10 times less capacity than to ganglioside GM₁. Binding of labeled toxin to both gangliosides was abolished in presence of excess amounts of unlabeled B subunit. Ganglioside extracts from human or pig intestinal mucosa showed toxin binding to gangliosides GM₁ and GD_1b. In ganglioside-containing lipid monolayers the penetration of the toxin was independent of the ganglioside binding capacity.Abbreviations GM₂ Gal-NAc14Gal(3-2NeuAc)14G1c1Cer - GM₁ Gal3Ga1-NAc14Gal(32NeuAc)14G1c11Cer - GD_1a NeuAc23Ga113Gal-NAc14Gal(32NeuAc)14G1c11Cer - GD1b Gall3Gal-NAcl4Gal(32NeuAc82NeuAc)14Glc11Cer - GT_1b NeuAc23Ga113Ga1-NAcal4Gal(3-2NeuAc82NeuAc)14G1c11Cer - dpPC 1,2-hexadecanoyl-sn-glycero-3-phosphocholine - dpPE 1,2-hexadecanoyl-sn-glycero-3-phosphoethanolamine     

Le réseau des cellules folliculo-stellaires et les follicules de l'adénohypophyse du rat (Pars distalis)

Résumé Dans l'hypophyse du rat, la microscopie électronique permet de mettre en évidence à l'intérieur de tous les cordons épithéliaux de la pars distalis un réseau de cellules agranulaires: les cellules stellaires et folliculo-stellaires, satellites des cellules granuleuses hormonogènes. Les cellules de ce réseau se caractérisent à la fois par la multiplicité de leurs prolongements et par leur organisation autour de cavités pour la plupart submicroscopiques, «les follicules». Les cellules folliculo-stellaires correspondent à une partie des cellules chromophobes de la microscopie photonique.La fente hypophysaire, par de nombreux caractères, semble faire partie de ce système folliculo-stellaire, dont elle pourrait représenter une région privilégiée par sa situation, ses dimensions et son contenu.L'existence des cellules folliculo-stellaires dans un grand nombre d'espèces, leurs caractères cytologiques hautement différenciés, leurs relations étroites avec le milieu intérieur interstitiel et leurs modifications en fonction de l'âge et des conditions expérimentales permettent de penser qu'elles sont étroitement attachées à la fonction glandulaire.

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The network of the folliculo-stellate cells and the follicles of the adenohypophysis in the rat (pars distalis)

Summary Electron microscopic investigation of the rat anterior pituitary reveals, throughout the whole pars distalis, a cellular network composed of agranular cells. These cells, the stellate and folliculo-stellate cells, are satellites of the granulated secretory cells.The cells of the network are characterized both by their multiple cytoplasmic processes and by their organization around cavities, most of them submicroscopic, the follicles. Those cells probably represent a large part of the chromophobe cells previously observed by light microscopy.On account of several characters, the pituitary cleft seems to be related to the réseau folliculo-stellaire and could be a peculiar part of this system because of its localization, size and contents.The réseau folliculo-stellaire is present in numerous species, showing a typical and differentiated cytology, and close relationships with the interstitial medium. Owing to its morphology and to modifications according to age and experimental conditions, this network seems to be a system intimately involved in the glandular function.

Je remercie Mr. le Professeur J. Racadot et toute l'équipe du Laboratoire pour l'aide apportée: Mme O. Racadot (clichés), Mme G. Porcile (tirages, manuscrit), Mlle B. Marie (technique), Mme A. Combrier (manuscrit). Ce travail a été effectué sous la direction de Mr. le Professeur L. Olivier que je remercie vivement pour ses conseils et pour son aide lors de la rédaction du manuscrit.     

Heterogeneity of epithelial cells in the human thymus

Summary To evaluate interrelationships among epithelial cells, and between morphology and function in the microenvironment, we studied the ultrastructural morphology of epithelial cells in sections of human thymus from donors aged 2 months to 31 years. Six types of epithelial cells were observed: subcapsular-perivascular (type 1); pale (type 2); intermediate (type 3); dark (type 4); undifferentiated (type 5); and large-medullary (type 6). Cells of types 2, 3 and 4 were found throughout the organ. The type-2 to -4 epithelial cells may represent various stages in a differentiation process. In this, type-2 cells are very active and type-4 cells are possibly degenerating elements. Type-4 cells can also contribute to Hassall's corpuscles. Type-5 cells were located mainly in the cortico-medullary region and showed the morphological characteristics of undifferentiated elements. Type-6 cells were located exclusively in the medulla and displayed characteristics of cellular activity. Small Hassall's corpuscles consisted of type-6 epithelial cells; in larger corpuscles many nuclei of type-6 cells were found. Cells of types 2 and 6 contained tubular structures (diameter approximately 20 nm).Concerning the function of thymus epithelial cells, the features associated with protein synthesis observed in cellular types 2 and 6 make them likely candidates for humoral factor-producing and/or secreting elements. In addition, type-2 and -3 cells in the cortex appear to contribute to a special pattern of epithelium-lymphocyte interaction (thymic nurse cells), as demonstrated by the intracytoplasmic location of lymphocytes in the epithelial cells. The various steps in intrathymic T-cell maturation occur at locations in a microenvironment composed of morphologically distinct epithelial cells.     

Ontogeny of gonadotropin releasing hormone and gonadotropin immunoreactivity in brain and pituitary of normal and estrogen-treated guppies,Poecilia reticulata Peters

Summary Gonadotropin releasing hormone (GnRH) and gonadotropic hormone (GTH) were identified by immunohistochemistry in the brains and pituitaries of neonate, juvenile and adult guppies. GTH was present in some cells of the pars intermedia (pi) and proximal pars distalis (ppd) of all animals. GnRH was found in the perikarya of the nucleus olfactoretinalis. In the pituitaries of juvenile 30-day-old guppies, GnRH-immunoreactive cells existed in a juvenile pattern, whereas in adult animals GnRH was recognized in only a few cells. GnRH-immunoreactive fibers were seen in the pituitaries of animals that were 30 days or older. In adult guppies, the ventral and lateral ppd (the gonadotropic region) contained a dense network of GnRH-immunoreactive fibers. Pituitary cells staining for either GnRH or GTH were located in different places. After immunohistochemical double staining of adult pituitaries, none of the GnRH-immunoreactive cells were LH-immunoreactive, although both cell types were often found in close proximity. After 20 days or more of ethinylestradiol treatment, less immunoreactive GnRH was detected in the pituitary cells of juvenile guppies, and fewer animals exhibited the juvenile pattern of GnRH-immunoreactive pituitary cells, when compared with untreated controls. The results indicate that GnRH-immunoreactive pituitary cells in the guppy are distinct from gonadotropes and that these cells are involved in regulatory processes along the juvenile brain-pituitary-gonad axis.     

Hypothalamus and cytodifferentiation of the foetal pituitary gland

Summary To investigate whether the hypothalamus is involved in the cytodifferentiation of the anterior pituitary gland, rat foetuses were encephalectomized in utero on day 16 of pregnancy.Pituitary sections from encephalectomized and normal littermate foetuses were studied on day 21 with the immunofluorescence technique using antibodies and -MSH, anti -MSH, anti -(17–39) ACTH and anti -(1–24) ACTH. On day 16, only the anti -MSH revealed a few cells in the pars distalis but not in the pars intermedia. On the other hand, on day 21, the pituitary cells reacting with antibodies anti -MSH, anti -MSH and anti -(17–39) ACTH were as numerous in the encephalectomized foetuses as in the normal littermate foetuses. The cells revealed with the antibody anti -(1–24) ACTH were less numerous and less fluorescent in the pars distalis and intermedia of the hypophysis of the encephalectomized foetuses.On day 21, the adrenals of the encephalectomized foetuses were atrophied in comparison with those of the normal littermate foetuses but they were larger than on day 16.These data suggest that the cytodifferentiation of the corticotroph and melanotroph cells of the hypophysis occurs without the influence of the hypothalamus which is necessary for the normal release of ACTH.     

Immunocytochemical study of Wulzen's cone of the bovine pituitary

Summary The Wulzen's cone of the bovine adenohypophysis presents a variable development and general arrangement. It is joined to the pars intermedia with no intervening connective tissue. It is covered by a single layer of cubical cell epithelium on the side of the hypophysial cleft. Immunofluorescence reveals the presence of different glandular cell types. The most abundant cells are those demonstrated by an anti-oPRL antibody and are either isolated or clustered. Other cells react with anti-hGH, anti-bLH, anti-oLH or anti-hTSH antibodies. Some cells react simultaneously with anti-MSH, anti-^1–24ACTH, anti-^17–39ACTH, anti-LPH and anti-endorphin antibodies. Cell types other than the numerous prolactin cells appear only as isolated elements. We did not observe cells reacting with anti-leu-enkephalin, anti-met-enkephalin or anti-calcitonin antibodies either in the Wulzen's cone or in the pars distalis or pars intermedia.

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Résumé Le cône de Wulzen de l'adénohypophyse bovine présente un développement et une disposition générale variables. Il est accolé à la pars intermedia dont il n'est séparé par aucune cloison conjonctive. Du côté de la fente hypophysaire, il est revêtu par un épithélium simple, cubique. En immunofluorescence, on observe la présence de divers types de cellules glandulaires: les plus abondantes sont des cellules mises en évidence par un anticorps anti-oPRL, isolées ou groupées en amas. D'autres cellules réagissent avec des anticorps anti-hGH, et anti-bLH, anti-oLH ou anti-/mTSH. Quelques cellules réagissent simultanément avec des anticorps anti-MSH, anti-^1–24ACTH, anti-^17–39ACTH, anti-LPH et anti-endorphine. Mises à part les nombreuses cellules à prolactine, les autres types cellulaires apparaissent constamment sous l'aspect d'éléments isolés. Nous n'avons pas observé de cellules réagissant avec des anticorps anti-leu-enképhaline, antiinet-enképhaline ou anti-calcitonine ni dans le cône de Wulzen, ni dans la pars distalis et dans la pars intermedia.

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Abbreviations used in this Article oPRL ovine prolactin - hPRL human prolactin - hGH human growth hormone - bLH bovine luteinizing hormone - oLH ovine luteinizing hormone - pFSH porcine follicle stimulating hormone - hFSH human follicle stimulating hormone - hTSH human thyrotropin - ACTH corticotropin - MSH a melanotropin - MSH melanotropin - LPH lipotropin - PD pars distalis - PI pars intermedia - PN pars nervosa - HC hypophysial cleft     

The ultrastructure of the epithelium of the ciliary body

Summary The fine structure of the human and rabbit ciliary body epithelium has been studied with the electron microscope, both under normal conditions and after paracentesis of the anterior chamber. The disposition of the junctional complexes in the two layers of the ciliary epithelium is described in detail. Junctional complexes appear particularly developed between the apical surfaces of the cells of the two layers, but are present, as in other monolayered epithelia, also between the lateral surfaces of adjacent cells of each layer. The junctional complexes connecting the apical surfaces of the cells of the two layers are represented by zonulae occludentes, zonulae adhaerentes and desmosomes following each other irregularly, with interposition of rounded dilatations of the intercellular space called ciliary channels. The zonulae occludentes and adhaerentes found along the lateral surfaces of the epithelial cells probably form discontinuous and overlapping fasciae. Moreover, the existence of a peculiar dove-tail arched junction called macula occludens is suggested. Few differences were encountered when comparing the arrangement of junctional complexes in the ciliary epithelium of man with that of the rabbit. Many desmosomes connecting the basal portion of lateral surfaces of the non-pigmented cells were found only in human ciliary bodies.The study of the modifications of the junctional apparatus of the ciliary epithelium following paracentesis of the anterior chamber, confirms the functional hypotheses on junctional complexes previously suggested: in particular only zonulae occludentes cause a real block of the intercellular spaces. On the basis of the present work, the close relationships between the number, kind and disposition of junctional complexes in epithelia and the functional possibilities of these epithelia are stressed.Dedicated to Professor W. Bargmann on his 60th birthday.Dr. Orzalesi is the recipient of a research grant from Ministero della Pubblica Istruzione for 1964.     

Ultrastructure and early development of the pore plate sensilla ofGymnomerus laevipes (Shuckard) (Vespoidea,Eumenidae)

Summary The oval pore plates (approx. 17 m long) are separated from the antennal cuticle by a furrow, the inner wall of which is flexible. The thin perforated plates are strengthened by an encircling and a middle ledge, the latter of which branches into about 100 almost parallel rims. Each pore plate is innervated by about 20 sense cells. The dendrites fork into numerous branches occupying the outer receptor lymph cavity below the perforated plate. Each pore plate is associated with one thecogen cell, two trichogen cells, one tormogen cell and one envelope cell 4. A so-called additional cell surrounds the sensillum in the imaginal stage. The envelope cells in the later of the two pupal stages examined, have reached an arrangement which immediately precedes the secretion of the cuticulin layer. The surface of the duplicate trichogen cells is almost equal in area to the completed perforated plate. A dendritic sheath, entirely reduced in the imago, protrudes into the exuvial space, where it encloses a single dendrite.In the younger pupal stage the Sensillenanlage forms a crater, whereby envelope cell 4 overtops the other envelope cells. The distal ends of the trichogen cells are divided into several appendages that form the bottom of the crater.     

Observations on the fine structure of the cercaria of Notocotylus attenuatus and formation of the cyst wall of the metacercaria

Summary The dorsal tegument of the mature cercaria of Notocotylus attenuatus is a syncytial, cytoplasmic layer, containing two types of secretory granule which are identifiable ultrastructurally. The type 1 secretory bodies are electron lucid, whereas most type 2 granules have a banded appearance. The ventral tegument contains granules which are secreted from the type 3 cells; the type 3 granules are membrane bound, electron dense, and consist of both an amorphous and a finely striated zone. The type 4 cells mainly contain cigar-shaped granules consisting of an amorphous core surrounded by concentric striations. The granules exhibit structural variability in shape and content. The type 4 cells undergo a cellular migration to the tegument during encystment. The structure of the posterior-lateral glands and mode of secretion of the granules are described. Possible functions of microtubules are discussed for each cell type. Details of some secretory processes involved in the formation of the hemispherical cyst wall are described. The layers of the cyst wall may be related to the granular contents of the various parenchymal cells of the cercaria. The tegument of the metacercaria originates primarily from the cytoplasm of the type 1, type 2, type 3 and type 4 cells.