Rosette morphology in zona glomerulosa formation and function.

How morphology informs function is a fundamental biological question. Here, we review the morphological features of the adrenal zona glomerulosa (zG), highlighting recent cellular and molecular discoveries that govern its formation. The zG consists of glomeruli enwrapped in a Laminin-ß1-enriched basement membrane (BM). Within each glomerulus, zG cells are organized as rosettes, a multicellular structure widely used throughout development to mediate epithelial remodeling, but not often found in healthy adult tissues. Rosettes arise by constriction at a common cellular contact point mediated/facilitated by adherens junctions (AJs). In mice, small, dispersed AJs first appear postnatally and enrich along the entire cell-cell contact around 10 days after birth. Subsequently, these AJ-rich contacts contract, allowing rosettes to form. Concurrently, flat sheet-like domains in the nascent zG, undergo invagination and folding, gradually giving rise to the compact round glomeruli that comprise the adult zG. How these structures impact adrenal function is discussed.

Development of adrenal cortical zonation and expression of key elements of adrenal androgen production in the chimpanzee (Pan troglodytes) from birth to adulthood.

The basis for the pattern of adrenal androgen production in the chimpanzee, which resembles that of humans, is poorly defined. We characterized the developmental zonation and expression of elements of the androgen biosynthetic pathway in the chimpanzee adrenal. The newborn adrenal contained a broad fetal zone (FZ) expressing CYP17, SULT2A1, and Cytochrome B5 (CB5) but not HSD3B; the outer cortex expressed HSD3B but not SULT2A1 or CB5. During infancy, the FZ involuted and the HSD3B-expressing outer cortex broadened. By 3years of age, a thin layer of cells that expressed CB5, SULT2A1, and CYP17 adjoined the medulla and likely represented the zona reticularis; the outer cortex consisted of distinct zonae fasiculata and glomerulosa. Thereafter, the zona reticularis broadened as also occurs in the human. The adult chimpanzee adrenal displayed other human-like characteristics: intramedullary clusters of reticularis-like cells and also a cortical cuff of zona fasiculata-like cells adjoining the central vein.

Effect of a water-rich diet on adrenal zona glomerulosa in Gerbillus tarabuli.

The objective of this work is to evaluate the aldosterone level and to study the gerbil adrenal zona glomerulosa morphology in the presence of an important water diet content during seven days. Thirty adult gerbils, Gerbilus tarabuli, were randomly assigned to two watering regimes, with fifteen gerbils per group. The first group was the control and the second group was exposed to a water-rich diet during seven days. Thin sections of the adrenal glands were observed in photonic and electron microscopy. Their blood was sampled and analyzed for aldosterone, electrolyte concentrations and hematocrit. Urine was collected after 24hours. A water-rich diet decreased the body weight but increased the hematocrit, total protein, aldosterone concentration and urine volume. In electronic microscopy, the adrenal zona glomerulosa cells present a decrease in lipid compartment and Golgi apparatus zone development. The blood electrolyte concentrations were not changed significantly. These findings indicate that the water-rich diet exerts a potent stimulatory effect on aldosterone secretion by the gerbil adrenal zona glomerulosa through plasma volume perturbation.

Alteration of subcapsular adrenocortical zonation in humans with aging: the progenitor zone predominates over the previously well-developed zona glomerulosa after 40 years of age.

Few studies have examined functional adrenal zonation throughout human life. Adrenals from 61 surgical/autopsy patients from 1 day old to 92 years old who had no clinical endocrinological/mineralocorticoid abnormalities were assessed for immunohistochemically defined adrenal zonation. The zona glomerulosa (zG) was well developed in all 11 patients ranging in age from newborn to the 30s. After 40 years of age, however, the zG occupied less than one-quarter of the adrenal circumference, suggestive of zG involution. The other subcapsular areas were occupied by the progenitor zone (zP), which expressed neither cytochrome P450(aldo) nor P450(11ß) but 3ß-hydroxysteroid dehydrogenase and P450scc, although some autopsy cases had adrenals with zG zonation because of secondary aldosteronism, and others who had experienced severe stresses showed subcapsular zona fasciculata (zF). In conclusion, the adrenal cortex consists of homogeneous zG-topped columns from birth to adolescence. Subsequently, in the fifth decade of life, the cortex is reconstituted by integration of three types of cortical columns: scattered zG-topped columns and zonal zP-topped columns, the latter having the ability for bidirectional differentiation into either zG-topped columns or zF-topped columns, according to secondary aldosteronism or the presence of severe stresses. Such adrenocortical remodeling is ascribed to high-sodium/low-potassium diets.

Adrenal glands of slaughtered bulls, heifers and cows: a histological study.

The study involved histological and immunohistochemical examinations of the adrenal glands of healthy slaughtered cattle. Glands of 13 bulls, 10 heifers and 10 cows were examined. The following histological findings were observed: Unequal thickness of connective capsule and nodular formations of the zona glomerulosa (ZG), eosinophilic granules in cells of the ZG, globoid arrangement of the zona fasciculata, nodules or pegs of cortical tissue in the medulla, mutual interlacing of superficial and deep zones of the medulla, proliferation of cortical or medullary cells into the blood vessels wall situated in the medulla and focal inflammatory infiltrates. Cortical cells and noradrenalin-secreting (N) cells in the medulla expressed cytoplasmic positivity of S100 protein. Both adrenalin (A) cells and N cells were positive in synaptophysin. The majority of the cells in the cortex and in the medulla displayed were positive for chromogranin A. Electron microscopy showed structureless, electrondense particles of varying size and shape, mostly displaying the having mostly character of secretory granules.

Prenatal development of the adrenal gland in the one-humped camel (Camelus dromedarius).

UNLABELLED: With 14 figures and 3 tables SUMMARY: Each adrenal gland consisted of cortex and medulla that developed from different embryological origins and presented different cellular organization. One hundred male or female camel embryos or fetuses with crown vertebral rump lengths (CVRL) that ranged from 0.8 to 117 cm were examined. The adrenal cortex, which is derived from intermediate mesoderm, was first observed in the 0.8-cm CVRL camel embryo. The adrenal cortex initially was combined with the gonad as a thickened region of proliferating cells derived from splanchnic intermediate mesoderm. Adrenocortical tissue was first separated from the gonadal tissue in the 2-cm CVRL camel fetus and was observed as a separate dorso-medial mass of cells. At 2.5-cm CVRL, the adrenocortical tissue was surrounded by a capsule of undifferentiated mesenchymal cells, except at its proximal pole, where an invagination was located through which chromaffinoblast cells entered the cortex. The chromaffinoblast cells migrated from the neural crest to form the medulla of the developing adrenal gland. In the 3.5-cm CVRL camel fetus, the adrenocortical cells differentiated into two layers: the inner fetal cortex and the outer definitive cortex. As development proceeded, the fetal cortex degenerated and the definitive cortex formed the zona glomerulosa and zona fasciculata. The zona reticularis did not form until the end of gestation. During prenatal life, the adrenal medulla was much thicker than the cortex.

Central effects of ghrelin on the adrenal cortex: a morphological and hormonal study.

Ghrelin, a growth hormone secretagogue that exerts an important role in appetite and weight regulation, participates in the activation of the hypothalamo-pituitary-adrenal (HPA) axis. Male Wistar rats (5/group) received daily for 5 days, via an ICV (intracerebroventricular) cannula, 5 microl phosphate buffered saline with or without 1 microg of rat ghrelin. Two hours after the last injection, blood and adrenal glands were collected from decapitated rats for blood hormone analyses and histologic and morphometric processing. Ghrelin treatment resulted in increased (p<0.05) body weight (13%), absolute whole adrenal gland weight (18%) and whole adrenal gland volume (20%). The absolute volumes of the entire adrenal cortex, ZG, ZF, and ZR also increased (p<0.05) after ghrelin by 20%, 21%, 21% and 11%, respectively. Ghrelin-treated rats had elevated (p<0.05) blood concentrations of ACTH, aldosterone and corticosterone (68%, 32% and 67%, respectively). The data clearly provide both morphological and hormonal status that ghrelin acts centrally to exert a global stimulatory effect on the adrenal cortex. Clarifying of the ghrelin precise role in the multiple networks affecting the stress hormone release, besides its well known energy and metabolic unbalance effects, remains a very important research goal.

Estereología renal en el cobayo (Cavia porcellus) / Renal stereology in the guinea pig (Cavia porcellus)

El cobayo (Cavia porcellus) es un roedor perteneciente al Orden Rodentia y a la Familia Caviidae, utilizado como animal de laboratorio y de consumo humano. Los parámetros cuantitativos del riñón entregan importante información de su morfofunción dada su labor en la homeostasis del organismo. El objetivo de este estudio fue describir el riñón de cobayo (Cavia porcellus), analizando las características estereológicas para futuros estudios experimentales. Se utilizaron 5 cobayos machos, obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. El riñón de cobayo pesó 3,2 g, aproximadamente. El riñón posee 140.298 glomérulos en total, Nv de 458 mm³, Vv de 7,89% y Sv de 3,58 mm²/ mm³. El volumen glomerular del riñón fue de 1,73 x 10(4)mm³ y el diámetro glomerular de 90 jm. Factores como especie, edad, peso corporal, peso y volumen renal, son importantes a considerar, ya que diferencian los resultados en investigaciones morfofuncionales.

The guinea pig, (Cavia porcellus) is a rodent pertaining to the Rodentia group and the Caviidae family, used as a laboratory animal and for human consumption. Quantitative parameters of the kidney provides important information of its morphofunction, given its labor in the organism's homeostasis. The aim or this study was to describe the kidney of the guinea pig (Cavia porcellus), analyzing the stereological characteristics for future experimental studies. Five male guinea pigs (Cavia porcellus) obtained from the Biotery of the Universidad de la Frontera, Temuco, Chile, were used. The kidney of the guinea pig weighed approximately 3.2g. The kidney has 140,298 total glomerulus, Nv of 458 mm³, Vv of 7.89% and Svof 3.58mm²/mm³. The glomerular volume of the kidney was of 1.73 x 10(4)mm³ and a glomerular diameter of 90 urn. Factors such as species, age, body weight and renal volume, are important to consider, as they differentiate the results in the morphofunctional investigations.

Determinación de parámetros estereológicos en el riñón de conejo (Oryctolagus cuniculus) / Determination of the stereological parameters in the kidney of the rabbit (Oryctolagus cuniculus)

El número y volumen glomerular contiene información importante sobre la morfofunción del riñón. El objetivo de este trabajo fue determinar algunos parámetros estereológicos, compararlos con los de otros estudios y determinar patrones de normalidad, para futuros estudios experimentales. Se utilizaron 5 riñones de conejo (Oryctolagus cuniculus), obtenidos del Bioterio de la Universidad de La Frontera, Temuco, Chile. Los riñones fueron disecados y fijados en formalina tamponada al 10 por ciento, realizando una breve descripción morfológica de ellos y determinando su volumen por el método de Scherle. Las muestras fueron obtenidas por Orientator e incluidas en Paraplast®. Se utilizó un fragmento de cada riñón y de cada uno de ellos se obtuvieron 5 cortes de 5 µm, los cuales fueron teñidos con H-E y Tricrómico de Masson. El volumen promedio obtenido del riñón de conejo, fue 11,4 mm3 + - 1,146mm3. El número promedio de glomérulos en el riñón fue 195,09 + - 84,78 x 103 glomérulos; un Nv de 17,1 + - 7,43 glomérulos por mm3 y un volumen glomerular de 4,2 x 10-4 x mm3 + - 0,8 x 10-4 x mm3. El número total de glomérulos del conejo Oryctolagus cuniculus, es menor al obtenido en ovejas por Eleanor et al. (2004) de 559.000 + - 198.000 y en perros por Horster et al. (1971) de 589.000; y mayor que en ratas por Bertram et al. (1992) de 31.764 + - 3.667. El volumen glomerular fue menor que en ratas (6,6 x10-4), que en ovejas 4,39x10-4 y mayor que en perros 1,2x10-4. Estas diferencias nos incentivaron a determinar otros parámetros estereológicos que permitirán iniciar una línea de investigación experimental en este animal.

The glomerular number and volume contain important information regarding the morphofunction of the kidney.The objective of this investigation was to determine some stereological parameters, compare them to those of other investigations and determine the normalcy patterns for future experimental investigations. Five rabbit (Oryctolagus cuniculus) kidneys from the Biotery of the Universidad de La Frontera, Temuco, Chile were used.The kidneys were dissected and set in buffered formalin at 10%, doing a brief morphological description of them and determining their volume via the Scherle method. The samples were obtained by Orientator and included in the Paraplast. One fragment of each kidney was used and serialized cuts of each one of these 5 µm were obtained, which were dyed with H-E and Masson´s Trichrome. The average volume obtained from the rabbit kidney was 11.4 mm3 ± 1.146mm3. The average number of glomerules in the kidney was 195.09 ± 84.78 x 103 gomerules; a Nv of 17,1 ± 7.43 glomerules per mm3 and a glomerular volume of 4.2 x 10-4 x mm3 ±0.8 x 10-4 x mm3. The total number of rabbit Oryctolagus cuniculus glomerules, is less than that obtained in sheep by Eleanor et al.(2004) of 559.000 ± 198.000 and in dogs by Horster et al. (1971) of 589.000and higher than in rats by Bertram et al. (1992) of 31.764 ± 3.667. The glomerular volume was less than in rats (6.6 x 10-4), than in sheep 4.39x10-4 and higher than in dogs 1.2x10-4. These differences are encouraging, in order to determine other stereological parameters which would allow for the initiation of an experimental line of investigation in this animal.

Ouabain chronic infusion enhances the growth and steroidogenic capacity of rat adrenal zona glomerulosa: the possible involvement of the endothelin system.

Ouabain, an inhibitor of the Na+/K+-ATPase, has been reported to affect the secretory activity of the adrenal cortex, and especially of zona glomerulosa (ZG). However, conflicting results were obtained, depending on the experimental condition used since ouabain appears to interact with angiotensin-II (Ang-II) and its action to be influenced by the electrolyte balance. Hence, we investigated the effects of prolonged (4-month) infusion with ouabain on the rat adrenal cortex. Ouabain raised the plasma concentrations of aldosterone, corticosterone and endothelin-1 (ET-1), without affecting either systolic blood pressure (SBP) or plasma renin activity (PRA). The treatment caused a marked hypertrophy of ZG and ZG cells, which mainly ensued from increases in the volume of the mitochondrial and smooth-endoplasmic-reticulum compartments, where the enzymes of steroid synthesis are located. Conversely, the volume of the lipid-droplet compartment, which stores cholesterol utilized in steroid-hormone production, underwent a striking decrease. Zona fasciculata and its parenchymal cells were not affected. Basal and maximally agonist (ACTH, Ang-II and ET-1)-stimulated in vitro mineralocorticoid secretion from adrenal slices was also notably enhanced by ouabain administration. Collectively, these findings indicate that prolonged treatment with ouabain selectively stimulates the growth and steroidogenic capacity of the rat adrenal ZG. The possibility that the activation of the renin-angiotensin system may be involved in this effect of ouabain is ruled out by the lack of significant changes in SBP and PRA. Instead, our results suggest the possible involvement of ET-1, the plasma level of which is elevated in ouabain-infused rats.

Aging alters zonation in the adrenal cortex of men.

Whereas aging has been shown to be associated with striking reductions in circulating levels of adrenal androgens in humans, the alteration in adrenal function that occurs in aging has not been identified. We sought to determine if there are changes in the zonation of the adrenal in aging men by performing histomorphologic analyses of adrenal specimens that had been obtained at autopsy following sudden death due to trauma. We evaluated adrenals from 21 young men (20-29 yrs) and 12 older men (54-90 yrs); inclusion criteria required the presence of medullary tissue in the specimen and fixation within the first 24 hrs postmortem. Sections stained with H/E were examined microscopically and areas of the cortex that included adjacent medullary tissue were chosen for quantitative evaluation by use of a computerized image analysis system. The average width (arbitrary units, pixels) of the zona reticularis and that of the combined zonae fasciculata/glomerulosa were determined from sections stained for reticulum fibers. The zona reticularis represented 37.1 +/- 1.9% of the total cortical width in the young men, which was significantly greater than that of the older men (27.1 +/- 3.3%, P = 0.0082). The zona fasciculata/glomerulosa to zona reticularis ratio in the young men (1.84 +/- 0.15) was significantly less that that of the older men (3.29 +/- 0.47, P = 0.0011). There was no significant difference in the total width of the cortex in young compared to older men. These data suggest that aging results in alterations within the cortex of the adrenals in men such that there is a reduction in the size of the zona reticularis and a relative increase in the outer cortical zones. A reduced mass of the zona reticularis could be responsible for the diminished production of dehydroepiandrosterone and dehydroepiandrosterone sulfate that occurs during aging.

The role of neuromedin B in the regulation of rat pituitary-adrenocortical function.

The effects of a 7-day administration of neuromedin B (NMB) and/or (Tyr4, D-Phe12)-bombesin, an NMB-receptor antagonist (NMB-A) on the function of pituitary-adrenocortical axis were investigated in the rat. NMB raised the plasma concentration of aldosterone, without affecting that of ACTH or corticosterone; the simultaneous administration of NMB-A prevented the effect of NMB. Neither NMB nor NMB-A treatments induced significant changes in adenohypophysis and adrenal weights, nor in the average volume of zona glomerulosa and zona reticularis cells. NMB-A administration lowered the volume of zona fasciculata cells, an effect annulled by the concomitant NMB administration. Our results suggest that NMB specifically stimulates aldosterone secretion, and that endogenous NMB or NMB-like peptides exert a tonic stimulating action on the growth of zona fasciculata cells.

Age related changes in the rat adrenal cortex.

The present study revealed that the growth of the rat adrenal gland was relatively slower than general body growth. However, growth of the cortex preceded that of the medulla. The parenchyma showed three usual zones but a fourth inconstant lipid-poor, zona intermedia between outer glomerulosa and middle fasciculata was also observed. In all cortical zones, the predominance of dark cells over the light cells occurred irrespective of the age groups studied. The advancing age replaced capsular cellular elements with fibrous ones whereas the mitotic activity of the parenchymal cells decreased and an increase in the intracellular lipid in the outer and ascorbic acid in the inner cortex was observed. The glycogen which was restricted mainly to the inner cortex remained unaffected by aging process while the acid phosphatase activity from the inner reticularis extended to the outer cortex in aged group.