Distribution and morphology of ghrelin immunostained cells in the adrenal gland of the African ostrich

Ghrelin is the endogenous ligand for the growth hormone secretagogue receptor. We investigated the distribution and morphological characteristics of ghrelin-immunopositive (ghrelin-ip) cells in the African ostrich adrenal gland. We found that the adrenal gland of the African ostrich consisted of three parts: capsule, inter-renal tissue and chromaffin cells. The inter-renal tissue and chromaffin cells interdigitated irregularly. The inter-renal tissue consisted of a peripheral zone and a central inner zone. The peripheral zone could be divided into an outer subcapsular zone and an inner zone. The subcapsular zone cells were arranged as a bow, while the inner area cells formed cords that were perpendicular to the capsule. The central inner zone exhibited irregular clumps and the cells were morphologically similar to chromaffin cells. Ghrelin-ip cells were located throughout the adrenal gland except the capsule. The majority of ghrelin-ip cells were found among the chromaffin cells. The number of ghrelin-ip cells in the inter-renal tissue decreased gradually from the central inner zone, to the inner zone to the subcapsular zone. The ghrelin-ip cells were oval or irregular in shape and exhibited cytoplasmic staining. Our findings suggest that ghrelin may play a role in regulating adrenal hormone secretion in the African ostrich.     

Morphology and ultrastructure of the adrenal gland in Bactrian camels (Camelus bactrianus)

In the present study, we examined the morphological features of the adrenal gland in Bactrian camel by means of digital anatomy, light and electron microscopy. Our findings testified that the gland was divided into three parts, capsule, cortex and medulla from outside to inside as other mammals, and the cortex itself was further distinguished into four zones: zona glomerulosa, zona intermedia, zona fasciculate and zona reticularis. Notably, the zona intermedia could be seen clearly in the glands from females and castrated males, whereas it was not morphologically clear in male. There was a great deal of lipid droplets in the zona fasciculate, while it was fewer in the zona glomerulosa and zona reticularis. The cytoplasm of adrenocortical cell contained rich mitochondria and endoplasmic reticulum. The adrenal medulla was well-developed with two separations of external and internal zones. The most obvious histological property of adrenal medulla cells were that they contained a huge number of electron-dense granules enveloped by the membrane, and so medulla cells could be divided into norepinephrine cells and epinephrine cells. Moreover, the cortical cuffs were frequently present in adrenal gland. Results of this study provides a theoretical basis necessary for ongoing investigations on Bactrian camels and their good adaptability in arid and semi-arid circumstances.     

An immuno-electron-microscopic study of the localization of VIP-like immunoreactivity in the adrenal gland of the rat

Summary VIP-like immunoreactivity was revealed in a few chromaffin cells, medullary ganglion cells and a plexus of varicose nerve fibers in the superficial cortex and single varicose fibers in the juxtamedullary cortex and the medulla of the rat adrenal gland. VIP-like immunoreactive chromaffin cells were polygonal in shape without any distinct cytoplasmic processes and they appeared solitarily. Their cytoplasm contained abundant granular vesicles having a round core and the immunoreactive material was localized to the granular core. VIP-immunoreactive ganglion cells were multipolar and had large intracytoplasmic vacuoles. The immunoreactive material was localized not only in a few granular vesicles but also diffusely throughout the axoplasm. VIP-immunoreactive varicose nerve fibers in the superficial cortex were characterized by abundant small clear vesicles and some large granular vesicles, while those in the juxtamedullary cortex and medulla and the ganglionic processes were characterized by abundant large clear vesicles, as well as the same vesicular elements as contained in the nerves in the superficial cortex. The immunoreactive material was localized on the granular cores and diffusely in the axoplasm in both nerves. Based on the similarity and difference in the composition of the vesicles contained in individual nerves, it is likely that the VIP-immunoreactive nerve fibers in the medulla and the juxtamedullary cortex are derived from the medullary VIP-ganglion cells, while those in the superficial cortex are of extrinsic origin. The immunoreactive nerve fibers in both the cortex and the medulla were often in direct contact with cortical cells and chromaffin cells, where no membrane specializations were formed. The immunoreactive nerve fibers were sometimes associated with the smooth muscle cells and pericytes of small blood vessels in the superficial cortex. In addition they were often seen in close apposition to the fenestrated endothelial cells in the cortex and the medulla, only a common basal lamina intervening. Several possible mechanisms by which VIP may exert its effect in the adrenal gland are discussed.     

Distribution and morphology of argyrophilic cells in the digestive tract of the African ostrich

We used light microscopy to elucidate the morphological features of argyrophilic cells in the digestive tract of the African ostrich (Struthio camelus). The results indicated that argyrophilic cells were found to be distributed among the epithelial cells of the mucosa or glands throughout the digestive tract, except for the esophagus; two types of argyrophilic cells were found; i.e., closed-type cells and cells with triangular or elongated shapes and with their apical cytoplasmic process in contact with the lumen (open-type cells); the greatest number of argyrophilic cells was found in the proventriculus, and the argyrophilic cell density gradually decreased from the proventriculus to the rectum; Furthermore, the number of argyrophilic cells in the duodenum and ileum was higher than that in the jejunum. This text still combined the characteristics that the argyrophilic cells in digestive tract of ostrich maybe related to different digestive function of different region and the basis of their morphology to carry on a discussion. It was speculated that argyrophilic cells in the digestive tract may have both endocrine and exocrine functions.     

Response of host embryonic chicks to grafts of additional adrenal glands

Summary The ultrastructure of the developing adrenal gland of the chick has been studied over the embryonic period 10 to 18 days.Cortical cells occur in double-rowed strands, are loosely attached in early development but more firmly attached later in development. Hypertrophy of mitochondria, endoplasmic reticulum, golgi body, lipid and vacuoles increases with increasing age. Two cell types (designated Dark and Light) were present at 17 days of incubation. Their significance is discussed.Medullary cells occur as single cells at 10 days but more usually in groups by 18 days. Catecholamine-containing granules are a prominent feature of the medullary cells, at all ages. Two cell types could be distinguished in the medulla at 17 days of incubation. These may represent adrenalin and noradrenalin-containing cells.Changes in the ultrastructure of host adrenal glands after exposure to an 18 day adrenal gland, grafted onto the host chorio-allantoic membrane at 8 days, were studied. The chief response within the cortex of the host involved retardation of organelle hypertrophy, so that 17 day hosts resembled 14 day controls. More light cells were seen in the host than in the control cells. The medullary tissue of the host was also retarded in development and the release of catecholamine-containing granules inhibited. The significance of these observations in relation to compensatory hypertrophy within the host is discussed.Supported by National Research Council of Canada Grant No. A 5056, and by a Dalhousie University Research Development Grant. HPH is a Post Doctoral Research Fellow, supported under Grant A 5056.     

Ultrastructure and melatonin 1a receptor distribution in the ovaries of African ostrich chicks

Healthy 90-day-old ostrich chicks were used in the present study. The ultrastructure and melatonin 1a receptor (MT1) distribution in the ovaries of ostrich chicks was observed by transmission electron microscope and light microscope. The results showed that the ostrich chick ovary contained primordial follicles, primary follicles and secondary follicles, but no mature follicles. There are some unique ultrastructural characteristics observed in the secondary follicle, such as the cortical granule, which was located in cytoplasm beside the nucleus and appeared first in the oocyte. The zona radiata appeared in the secondary follicle, and there was an obvious vitelline membrane. There were intraovarian rete, connecting rete, and extraovarian rete in the ovaries of ostrich chicks. This is the first study that provides immunohistochemical evidence for the localization of the melatonin MT1 in the ostrich chick ovary. The germinal epithelium, follicular cell layer of every grade of follicle, cytoplasm of the oocyte and interstitial cells all expressed MT1. The expression of positive immunoreactivity materials was the strongest in the follicular cell layer of the primordial follicle and germinal epithelium, was weaker in the follicular cell layer of the primary follicle and secondary follicle, and was weakest in the oocytes of all grades of follicle. In addition, the extraovarian rete displayed strong positive expression of MT1, while there was no positive expression in the intraovarian rete or connecting rete. The positive expression of MT1 immunoreactivity in the ovary was very strong, implying that the ovary is an important organ for synthesizing MT1.     

Effect of a low calcium diet on the ultrastructure of the parathyroid gland of chicks

Summary The effect of a low calcium diet on the ultrastructure of the parathyroid gland in the chick was examined. Two-week-old White Leghorn chicks were fed a low calcium diet (calcium content 0.63%) for two weeks. In these chicks, the parathyroid glands are grossly enlarged. Hypertrophy and hyperplasia of the chief cells are evident. The plasma membranes between adjacent cells are relatively straight but interdigitate in some places. Chief cells contain occasional membrane-limited secretory granules (150–350 m in diameter) and with contents of variable electron density. Secretory granules are distributed randomly but some are closely applied to the plasma membrane. There is an increase in the development of the rough-surfaced endoplasmic reticulum. The Golgi complex is enlarged and consists of cisternae arranged in concentric layers, smooth-surfaced and coated vesicles and condensing vacuoles. Dilatations of the cisternae at several points are observed. Mitochondria and filaments are also encountered. These morphological features suggest that low calcium intake stimulates the synthetic activity of the chief cells of the chick parathyroid.     

Further data on the existence of a neural pathway from the adrenal gland to the hypothalamus

Summary The effect of unilateral adrenalectomy on the incorporation of tritiated leucine into the ventromedial nucleus of both sides of the rat hypothalamus was studied by light- and electron-microscopical autoradiography. The left adrenal had been removed and 14 days later labeled amino acid was given intravenously. Rats were killed 5, 30, 60 and 120 min after isotope administration. Following unilateral adrenalectomy there is a marked difference in the autoradiographic reaction of both sides of the hypothalamic ventromedial nucleus. On the right side the number of autoradiographic silver grains is much higher than on the left side, the difference being statistically significant for each animal and for each time interval. In accordance with previous findings the data suggest the existence of a neural pathway from the adrenal gland to the hypothalamus.     

Functional differences between two structurally distinct types of steroidogenic cell in the avian adrenal gland

Summary There are two regions of steroidogenic cells in the duck adrenal gland. An outer, subcapsular zone (SCZ), consisting of cells with irregularly shaped nuclei, shows relatively little smooth endoplasmic reticulum and mitochondria with shelf-like cristae. This region surrounds the inner zone (IZ) of the gland which is comprised of smaller cells with rounded nuclei, a more abundant smooth endoplasmic reticulum and mitochondria with tubular cristae. When samples of tissue from these distinct regions of the gland are superfused in vitro with media containing concentrations of 1–24 ACTH ranging from 100 to 1000 ng per ml (0.034 to 0.34 M) the steroidogenic cells in both zones release corticosterone in a dose-dependent manner. The dose-responsiveness of both the SCZ and the IZ cells over this range is a complex quadratic function of the 1–24 ACTH concentration in the medium and the semilogarithmic linear portions of the dose-response curves are restricted to a narrow midrange of ACTH concentrations. Throughout the dose-response range, however, the steroidogenic cells of the IZ are more responsive to corticotropic stimulation than are the cells of the SCZ. The cells of the two zones are further distinguished by their responses to a challenge for a second time with medium containing 1–24 ACTH; the responses of the IZ cells to a second challenge were greater than those of the SCZ cells, and at a high concentration of ACTH the SCZ slices showed no significant second response.This work was supported by a grant from the National Science Foundation (PCM 79-15777) to James Cronshaw and W.N. Holmes     

Annual variations of adrenal gland hormones in the lizard <Emphasis Type=Italic>Podarcis sicula</Emphasis>

The adrenal gland regulates metabolism and maintains normal electrolyte balance. Adrenal hormones are equivalent in all vertebrates; the chromaffin tissue produces adrenaline and noradrenaline and the steroidogenic tissue produces most of the steroid hormones present in mammals. Podarcis sicula belongs to the Squamata family of lizards and it is the most abundant lizard species in southern Italy. This species shows a reproductive annual cycle and the presence of seasonal variations in the activity of the hypothalamus-hypophyseal-thyroid axis. To investigate the existence of an annual cycle of lizard adrenal gland, we have measured plasma concentrations of corticosterone, ACTH, noradrenaline and adrenaline. We have shown that corticosterone rapidly increased from January to March to reach a peak value that persisted until July, then, it slowly decreased until December. ACTH levels increased from January to May and slowly decreased from July to December. Noradrenaline levels were higher in March and then decreased until December. On the contrary, adrenaline levels increased from March to July and slowly decreased until December. Our results demonstrate the existence of an annual cycle of the lizard adrenal gland activity. This is very interesting because its activity is important to rightly regulate the reproductive status of the Podarcis sicula lizard.     

Effect of melatonin on norepinephrine,epinephrine, and corticosterone contents in the adrenal gland of three avian species

Summary A single melatonin injection was administered intraperitoneally to three avian species in two doses (250 and 500 g · 100 g body wt^–1). Norepinephrine (NE), epinephrine (E), and corticosterone (C) contents of the adrenal gland were measured spectrofluorometrically 0.5, 2, and 24 h after injection. The results showed that melatonin at the lower dose caused a decrease of NE content in bulbul (42%), babbler (52%), and pigeon (39%), while at the higher dose it resulted in a decrease of NE only in bulbul (51%) 0.5 h after treatment. Melatonin at the lower dose also caused a decrease of NE in bulbul (45%) and babbler (53%) 2 and 24 h, respectively, after treatment, while at the higher dose it resulted in an increase of NE in bulbul (82%) and a decrease of NE in babbler (44%) 24 h after injection.Both low and high doses of melatonin resulted in a decrease of E content in bulbul (32–43%), babbler (34–43%), and pigeon (44–56%) 0.5 h after treatment, and a 34–46% decrease of E in bulbul and a 32–33% decrease of E in babbler 2 h after treatment. A 57% decrease of E was evident in pigeon with the lower dose of melatonin 2 h after injection. Melatonin at the higher dose caused a 67% increase of E in babbler and a 41% decrease of E in pigeon 24 h after administration. Melatonin at the lower dose resulted in an increase of C content in bulbul (70%), babbler (132%), and pigeon (69%) 0.5 h after treatment. A 60% increase of C was evident in pigeon following the lower dose of melatonin 24 h after injection. Melatonin at the higher dose resulted in an increase of C in the bulbul of 72% and 86% at 0.5 and 24 h, respectively, after treatment. The results indicate that melatonin produces significant changes of NE, E, and C contents in three avian species. The lower dose appears to be more effective in changing NE and C content.Abbreviations C corticosterone - CA catecholamine - DBH dopamine -hydroxylase - E epinephrine - NE norepinephrine     

The fine structure of the vesicular component of the ultimobranchial gland of the domestic fowl

Summary The ultrastructure of the polymorphic vesicular component of the ultimobranchial gland of the domestic fowl (Gallus gallus domesticus) has been described in detail, together with the structure of the cell strands interconnecting the vesicles and the parathyroid nodules lying within the ultimobranchial stroma. The vesicles frequently appear to arise from the nodules by way of the cell strands. The strands show a structure of their component cells intermediate between that of the parathyroid and the vesicular cells, although the position at which the strand changes from an essentially parathyroid structure to an essentially vesicular structure is very variable. The degree and kind of secretory activity within different cell types has been described. A review of the structure of ultimobranchial glands throughout the vertebrates shows that similar tissue with a similar secretory potential has been observed in all vertebrate classes, suggesting a functional significance for this part of the gland.     

Respiratory motion of adrenal gland metastases: Analyses using four-dimensional computed tomography images

PurposeTo evaluate the respiratory motion of adrenal gland metastases in three-dimensional directions using four-dimensional computed tomography (4DCT) images.MethodsFrom January 2013 to May 2016, 12 patients with adrenal gland metastases were included in this study. They all underwent 4DCT scans to assess respiratory motion of adrenal gland metastases in free breathing state. The 4DCT images were sorted into 10 image series according to the respiratory phase from the end inspiration to the end expiration, and then transferred to FocalSim workstation. All gross tumor volumes (GTVs) of adrenal gland metastases were drawn by a single physician and confirmed by a second. Relative coordinates of adrenal gland metastases were automatically generated to calculate adrenal gland metastases motion in different axial directions.ResultsThe average respiratory motion of adrenal gland metastases in left-right (LR), cranial-caudal (CC), anterior-posterior (AP), 3-dimensional (3D) vector directions was 3.4 ± 2.2 mm, 9.5 ± 5.5 mm, 3.8 ± 2.0 mm and 11.3 ± 5.3 mm, respectively. The ratios were 58.6% ± 11.4% and 63.2% ± 12.5% when the volumes of GTV_In0% and GTV _In100% were compared with volume of IGTV_10phase. The volume ratio of IGTV_10phase to GTV_3D was 1.73 ± 0.48.ConclusionsAdrenal gland metastasis is a respiration-induced moving target, and an internal target volume boundary should be provided when designing the treatment plan. The CC motion of adrenal gland metastasis is predominant and >5 mm, thus motion management strategies are recommended for patients undergoing external radiotherapy for adrenal gland metastasis.     

Morphological changes in the submandibular glands and in the X zone of the adrenal gland following ovariectomy in mice

Summary Morphological changes in submandibular glands of female mice following ovariectomy were studied morphometrically by light microscopy and ultrastructurally by electron microscopy. The X zone of the adrenal gland was examined in order to assess possible changes that might be expected to occur after ovariectomy.In submandibular glands, 1 to 4 weeks after ovariectomy, no changes were observed in percentages of the acinar, intercalated duct, and granular convoluted tubular areas occupying photomicrographs. However, an increase in the granular content of both intercalated duct and granular convoluted tubular cells was recognized. By contrast, the glandular picture 4 months after ovariectomy changed remarkably, resembling that of the male mouse both morphometrically and in terms of fine structure. In the adrenal cortex of control female mice, the X zone became thinner with aging. As compared with this, the X zone of ovariectomized mice at any time after the operation was thicker than that of controls.These observations suggest that the absence of ovarian hormones in the ovariectomized mouse may lead to prolonged functioning of X zone cells, which in turn may cause masculinization of the submandibular gland.     

Changes in the adrenal cortex of the rat after chronic administration of the steroidogenic inhibitor U-8113

In concert with studies of the effects of various pharmacologic inhibitors of corticosteroidogenesis on adrenocortical morphology, U-8113, an analog of amphenone B, was administered daily to Sprague-Dawley rats for 7, 14, 21 or 30 day. The primary morphological responses involved increases in adrenal weight, width of zona fasciculata, width of zona reticularis, intracellular lipids, mitochondrial size, mitochondrial vacuolation and crystalline-like inclusions, small coated vesicles, lysosomes, autophagic vacuoles and cholesterol ester clefts. In particular, the increases in lysosomes, coated vesicles and autophagic vacuoles containing morphologically altered mitochondria were considered reflective of mechanisms designed to maintain cellular integrity amidst functional impairment. Lipid analysis revealed marked increases in cholesterol esters and phospholipids, supportive of morphological observations. When permitted a 14 day recovery period following either 14 or 30 days of inhibitor therapy, most fine structural alterations and lipid derangements were diminished, and the cells approximated normal parameters.     

A study of the vascular arrangement in the rat adrenal gland using non-radioactive microspheres

Summary The intra-glandular vascular arrangement in the adrenal has been studied using non-radioactive microspheres injected by three different routes: in-vivo injection into the left ventricle under pentobarbital anesthesia, postmortem orthograde, and postmortem retrograde injection. The doses of microspheres were 10⁵ (average size 24.7 m), 10⁶ (15.8 m) and 10⁷ (9.9 m). The entrapment rate of microspheres by the medulla as compared with the whole gland was measured in the serially sectioned tissue (section thickness 60 m).The entrapment rates of 25-m microspheres differed between the orthograde and retrograde injections, while the entrapment rates for 15-m microspheres were essentially similar irrespective of the route of injection.Our results support the conclusion from previous microangiographic studies that the adrenal cortex and medulla are supplied by different arteries but have a common venous outflow, and that direct communication between cortical and medullary sinusoids is not likely. The medullary blood flow per gram tissue weight is estimated to be larger than cortical blood flow.     

Calcitonin gene-related peptide (CGRP)-like immunoreactivity in scattered chromaffin cells and nerve fibers in the adrenal gland of rats

Summary The present immunohistochemical study reveals that a small number of chromaffin cells in the rat adrenal medulla exhibit CGRP-like immunoreactivity. All CGRP-immunoreactive cells were found to be chromaffin cells without noradrenaline fluorescence; from combined immunohistochemistry and fluorescence histochemistry we suggest that these are adrenaline cells. In addition, all CGRP-immunoreactive cells simultaneously exhibited NPY-like immunoreactivity. CGRP-chromaffin cells were characterized by abundant chromaffin granules with round cores in which the immunoreactive material was densely localized. These findings suggest the co-existence of CGRP, NPY and adrenaline within the chromaffin granules in a substantial number of chromaffin cells.Thicker and thinner nerve bundles, which included CGRP-immunoreactive nerve fibers, with or without varicosities, penetrated the adrenal capsule. Most of them passed through the cortex and entered the medulla directly, whereas others were distributed in subcapsular regions and among the cortical cells of the zona glomerulosa. Here the CGRP-fibers were in close contact with cortical cells. A few of the fibers supplying the cortex extended further into the medulla. The CGRP-immunoreactive fibers in the medulla were traced among and within small clusters of chromaffin cells and around ganglion cells. The CGRP-fibers were directly apposed to both CGRP-positive and negative chromaffin cells, as well as to ganglion cells. Immunoreactive fibers, which could not be found close to blood vessels, were characterized by the presence of numerous small clear vesicles mixed with a few large granular vesicles. The immunoreactive material was localized in the large granular vesicles and also in the axoplasm. Since no ganglion cells with CGRP-like immunoreactivity were found in the adrenal gland, the CGRP-fibers are regarded as extrinsic in origin. In double-immunofluorescence staining for CGRP and SP, all the SP-immunoreactive fibers corresponded to CGRP-immunoreactive ones in the adrenal gland. This suggests that CGRP-positive fibers in the adrenal gland may be derived from the spinal ganglia, as has been demonstrated with regard to the SP-nerve fibers.     

Short- and long-term effects of vinblastine on the rat adrenal medulla

Summary The effects of a single high dose (10mg/kg) of vinblastine (vb) sulfate (Velbe, Lilly) on the ultrastructure, catecholamine (CA) content and activity of CA-synthesizing enzymes of the rat adrenal medulla were studied for up to 120h after intravenous injection of the drug.By 1 h, microtubules were virtually absent from chromaffin cells and preganglionic cholinergic axons, and typical paracrystals had appeared inside the nerve fibers. By 16h microtubules were completely reconstituted and paracrystals had disappeared. From 16h onwards, there was an increasing depletion of storage granules from adrenaline (A) — producing cells, which coincided with biochemical determinations showing a reduction of adrenal A to about 40 % of control levels by 48 h, with noradrenaline (NA) remaining in the range of controls. Both A- and NA-storing cells showed an extensive proliferation of the rough endoplasmic reticulum (ER). Vb caused a marked increase in tyrosine hydroxylase (TH; +113%) and dopamine -hydroxylase (DBH; +82%) activities after 48 h. Splanchnicotomy completely abolished the vb-mediated increase in TH and DBH activities. A smaller increase (+ 47 %) in enzyme activity was observed with phenylethanolamine N-methyltransferase (PNMT). Vb (10^–5M) had no apparent effect on granule content and the amount of rough ER in chromaffin cells, which were cultured for 48 h.The results demonstrate that a single high dose of vb has relatively little short-term effects on the rat adrenal medulla, but causes drastic long-term changes in CA-content and enzyme activities that are mediated by the preganglionic nerves. These changes could be interpreted as an effort to compensate for a loss of CA-stores in peripheral adrenergic nerves (cf. Cheney et al., 1973). The differential long-term effect of vb on adrenal NA and A might be due to the lower induction of PNMT as compared to TH and DBH activities and/or to a preferential release of A versus NA, which may occur at high frequencies of stimulation of the splanchnic nerves.Supported by grants from the Deutsche ForschungsgemeinschaftDedicated to Professor G. Petry in honor of his 65th birthday