Showing papers on "Adrenal cortex published in 1978"

The renin-angiotensin-aldosterone system. Past, present and future.

Abstract: "The present results indicate that there is a close relationship between the incretory function of the kidney, which is shown by the discharge of renin and similar materials, and the function of the adrenal cortex, especially the zona glomerulosa, which is the place of production of the sodium-retaining hormone aldosterone . Salt load inhibits the production of renin and aldosterone, while salt deprivation stimulates the production of both. The excess of sodium-retaining corticoids (DOC or aldosterone) together with sodium suppress the secretion of renin, while a deficiency of cortical hormones (adrenalectomy, morbus Addison) increase it." ... "Under these conditions the development of experimental renal hypertension could be explained as follows: the narrowing of the renal artery stimulates the secretion of renin which itself increases the formation or discharge of mineralocorticoid hormones (aldosterone or similarly acting corticoids). The resulting retention of sodium does not lead to the normal reduction of renin secretion in the ischemic kidney, so that corticoid production in the adrenal cortex is further stimulated despite no need for it."

Angiotensin II receptors and aldosterone production in rat adrenal glomerulosa cells.

Abstract: Specific receptors for angiotensin II (A II) were demonstrated in membrane fractions and collagenase- dispersed cells from the zona glomerulosa of the rat adrenal gland. The equilibrium association constant (Ka) of the A II binding sites was similar in particulate fractions (2.0 ± 0.4 (SE) × 109 M-1) and intact glomerulosa cells (1.8 ± 0.3 × 109 M-1). Specific binding of [125I]iodo-A II was enhanced by increasing sodium concentration, and in the presence of dithiothreitol, EDTA, and EGTA. Plasma membrane fractions prepared by density gradient centrifugation showed increased binding of [125I]iodo-A II, and were correspondingly enriched in adenylate cyclase and sodium-potassium- dependent ATPase. Steroid production by collagenase-dispersed adrenal glomerulosa cells was highly responsive to A II and ACTH. Significant increases in aldosterone and corticosterone production were elicited by A II concentrations as low as 3 × 10-11, equivalent to normal blood levels of A II in rats (5 × 10-11). The maximum increa...

Prolactin and adrenal androgen secretion

Abstract: The aim of this study was to investigate the role of prolactin in the secretion by the adrenal of dehydroepiandrosterone (DHA) and its sulphate (DHA-S). Therefore prolactin and DHA-S levels were determined in different groups of subjects under various physiological and pathological conditions. In patients with prolactinomas, or with pharmacologically induced hyperprolactinaemia, plasma DHA-S and, to lesser extend, DHA concentrations were elevated, and the DHA-S blood production rate greatly increased. ACTH stimulation which did not influence DHA-S concentrations in normals, caused a significant increase in patients with prolactinomas; the increase in DHA concentrations was similar in normal subjects and in prolactinoma patients. Bromocriptine treatment of prolactinaemia patients normalized both prolactin and DHA-S concentrations. Acute elevation of prolactin in normal subjects by TRH stimulation or by short term administration of sulpiride, in contrast to long term treatment, did not influence DHA-S levels. During pregnancy, notwithstanding high prolactin concentrations, DHA-S concentrations were lower than during the menstrual cycle. In patients with prolactinomas, given glucocorticoid replacement with cortisol, DHA-S concentrations were low (normal) notwithstanding persistently high prolactin concentrations. It is concluded that only prolonged elevation of prolactin induces increased DHA-S secretion by the adrenal cortex and that normal ACTH secretion is a prerequisite for this effect. The absence of elevated DHA-S concentrations in pregnancy might be explained by the rapid rate of metabolism, as the DHA-S production rate is increased. The intimate mechanism of prolactin and ACTH interaction at the adrenal cortex remains however unknown.

Some age-related changes in pituitary-adrenal function in the male laboratory rat.

Abstract: Changes in the pituitary-adrenal axis have been investigated as a function of age (2 1/2 to 26 mo) in the male laboratory rat (CFY-Sprague Dawley). Ether stress was used to challenge the pituitary-adrenal axis and blood samples (peripheral and adrenal venous effluent) taken for measurement of corticosterone using the competitive protein-binding assay and ACTH by the increase in corticosteroidogenesis in isolated rat adrenal cells. The results show that there was an increase of basal ACTH levels with increase in age which might be correlated with the degenerative changes in the adrenal cortex at old age. No age difference was observed in the 2 1/2-min stress levels. However, 15-min stress resulted in a further increment of ACTH levels, which was not found in old animals. No age-related differences in the basal and stress levels of corticosterone was observed, and, hence, adrenocortical function would seem not to be impaired in old age.

The Adrenal Cortex of Amphibia

Abstract: Publisher Summary This chapter discusses the structure of the adrenal islets and functions of adrenocortical secretions. Amphibian adrenocortical tissue secretes steroid hormones of the accepted vertebrate type, the major ones being corticosterone and aldosterone. Anatomically, it differs from the gland in Amniota in that it lies ventrally on the kidney and intermingles with the renal tubules and interstitium. The adrenocortical homologue comprises discrete or scattered tissues set about the ventral surface of the functional opisthonephros kidney. Bilateral branches of the dorsal aorta supply both the gland and the kidneys. The blood exits through venules into renal veins to enter the posterior vena cava. Venous blood from the renal portal vein enters numerous small vessels to reach the outer edges of the kidneys and is also carried to the vena cava by the renal veins. The inter-renal islets are on the ventro-median surface of each kidney in the anuran type and are set principally in the midline between the two kidneys in the urodelan type. With the low power light microscope, adrenal islet cells are seen to contain fat, which gives a characteristic appearance. In general, the adrenal islets of Anura are arranged to form more or less compact strands. In the Urodela, the islets are mostly cast into patches seen along the midline where the two halves of the kidney meet.

Studies on Cyclic Nucleotides in the Adrenal Gland. VIII. Effects of Angiotensin on Adenosine 3′,5′-Monophosphate and Steroidogenesis in the Adrenal Cortex

Abstract: Effects of angiotensin II on corticoid biogenesis and cAMP levels in the zona fasciculata-reticularis (the decapsulated fraction) and the zona glomerulosa (the capsular fraction) from the rat adrenal gland have been studied. Angiotensin II exclusively stimulated steroidogenesis in the zona glomerulosa without stimulation of the cAMP system, suggesting that steroidogenic action of this polypeptide does not involve the adenylate cyclase system. Angiotensin II was also found to stimulate cAMP-phosphodiesterase activity in the zona glomerulosa. An elevation of calcium concentration in the incubation medium has been observed to be effective in stimulating the production of aldosterone and cAMP by the capsular fraction. Angiotensin II caused a significant enhancement of the steroidogenic response of the capsular fraction to increasing calcium concentration regardless of the response of the cAMP system to calcium. This steroidogenic effect of angiotensin II was completely abolished by calcium antagonists added t...

Intracellular Prolactin in Rat Corpus Luteum and Adrenal Cortex

Abstract: This study was done to examine whether PRL, which appears in both active milk secretory cells (MSC) (1) and milk (1, 2) during normal lactation, could also be detected in PRL target cells which do not transfer this hormone into an exocrine secretory product. Ovaries, adrenals, and mammary and pituitary glands were collected from actively nursing rats decapitated on day 15 post-partum. All four tissues were processed for light microscopic immunohistochemical identification of PRL. Immunoreactive PRL was again found in pituitary PRL cells and in MSC. It was also detected within both lutein and adrenal cortical cells (zona fasciculata). In all three target tissues, PRL was present in target cell cytoplasm, but, in MSC and adrenal cells, it was also found occasionally in nuclei. These findings, which seem to indicate that transfer into an exocrine secretory product cannot be the only possible explanation for the appearance of this protein hormone inside its target cells, extend the evidence suggesting that PR...

The Structure of the Mammalian Adrenal Cortex

Abstract: Publisher Summary This chapter discusses the problems of adrenocortical structure using histochemical and ultrastructural techniques. In embryological development, adrenocortical cells arise from mesoderm, particularly from the columnar epithelial cells that line the coelom. Chromaffin cells have a separate origin, coming from neighboring paraganglion cells of the neural crest complex and thence migrating to lie adjacent to cortical cells. This intermingling is characteristic of most submammalian vertebrates though Elasmobranchii display complete separation. In Mammalia, the adult adrenal gland shows coalescence of chromaffin tissue and in Eutheria and Metatheria it lies centrally and is termed the medulla and eccentrically in the Prototheria. It is only over the past 10 years that the role of organelles in the biosynthesis of steroid hormones has begun to be delineated with correlated changes in fine structure. Changes occur in the smooth endoplasmic reticulum—the surface of which increases in area when the rate of steroidogenesis rises— and the mitochondrial cristae, which are usually tubular or vesicular in steroid secreting cells. Lamelliform cristae differentiate into tubular then vesicular cristae in most species studied. This is related to adrenocortical stimulation, for example, by ACTH. Thus, in hypophysectomized animals, the predominant tubular type is changed to vesicular by the administration of ACTH.

Adrenal scintigraphy. [/sup 131/I tracer techniques]

Abstract: Adrenal scintigraphy has been clinically feasible since the development of /sup 131/I-19-iodocholesterol in 1970. This agent has been supplanted by the current agent of choice, 6-iodomethyl-19-norcholesterol. Patients receive Lugol's iodine to block the thyroid gland and receive 1 to 2 mCi of radiocholesterol intravenously. Imaging is accomplished 4 to 7 days postinjection with the gamma camera. Adrenal percent uptake determinations similar to thyroid uptakes may be accomplished with the aid of a digital computer and standard percent uptake curves derived from phantom studies. Adrenal suppression scans were developed to enhance differences between the normal and abnormal adrenal cortex in certain clinical conditions. Patients receive dexamethasone prior to radiotracer injection, and serial scans beginning 2 to 3 days postinjection are obtained. In the normal adrenal scintigram, the right adrenal gland is higher than the left and appears slightly hotter. The left adrenal has an oval configuration, while the right adrenal has a truncated or circular configuration in most subjects. Knowledge of the patient's clinical hormonal status is necessary for proper scintigraphic interpretation. With documented glucocorticoid excess, symmetrical visualization is due to adrenal hyperplasia, usually secondary to Cushing's disease. Unilateral visualization indicates the presence of an adenoma or a postsurgical adrenal remnant;more » and bilateral nonvisualization is typically due to carcinoma. On dexamethasone suppression scans in primary aldosteronism and adrenal androgenism, adenomas demonstrate unilateral or markedly asymmetrical uptake. Patients with micro- and macronodular hyperplasia typically demonstrate bilateral breakthrough in contrast to normal subjects in whom there should be no visualization while on dexamethasone suppression.« less

Different types of small granule-containing cells and neurons in the guinea-pig adrenal medulla.

Abstract: An electron microscopic, histo- and biochemical study was carried out on the adrenal medulla of newborn and adult guinea-pigs giving special emphasis to small granule-containing (SGC) cells. Adrenaline (A) was the predominating catecholamine (CA) both in newborn (70-90% of total CA) and adult (85-90%) guinea-pig adrenals. In analogy to the biochemical findings electron microscopy revealed a high predominance of A cells, which contained large granular vesicles with an average diameter of 180 nm. Most noradrenaline (NA) storing cells showed granular vesicles of a considerably smaller average diameter (80 nm) and had a higher nuclear-cytoplasmic ratio. These cells were termed SGC-NA cells. NA cells with large granular vesicles (average diameter 170 nm) were extremely rare. Another type of SGC cells contained granular vesicles with cores of low to medium electron-density (SGC-NA-negative cells). Biochemical determinations made it unlikely that these cells contained predominantly dopamine (DA). SGC cells were scarcely innervated by cholinergic nerves. They formed processes, which were found both in the adrenal cortex and medulla contacting blood vessels including sinusoid capillaries, steroid producing cells of the reticularis and fasciculata zone and processes, which were interpreted to belong to medullary nerve cells. Two types of neurons were present in the guinea-pig adrenal medulla, one resembling the principal neurons in sympathetic ganglia, the other, which, principal neurons and SGC cells. In adrenomedullary grafts under the kidney capsule, which were studied three weeks after transplantation, "ordinary" A cells resembled SGC-NA negative cells with respect to their ultramorphology. Processes of transplanted principal neurons showed uptake of 5-hydroxydopamine and, hence, were considered to be adrenergic. Despite the lack of extrinsic nerves to the transplants, few principal neurons received cholinergic synapses, the origin of which is uncertain to date.

Physiological evolution of the renin-angiotensin system.

Abstract: The renin-angiotensin system (RAS) in mammals may participate in the controls of blood pressure and aldosterone secretion, and possibly in the regulation of renal function. It has been shown that renin release is controlled by:1) two intrarenal receptors, the renal arteriolar receptor and the macula densa; 2) the sympathetic nervous system; and 3) several humoral agents. Recent studies indicate interrelations between the RAS and renal prostaglandins and the kallikrein-kinin system. Comparative studies have revealed that renal renin and the juxtaglomerular (JG) cells emerged during the early evolution of bony fishes, wherease the macula densa evolved later in the vertebrate phylogney. Exogenously administered angiotensins and renin produce vasopressor actions in representative species of all vertebrate classes from elasmobranchs to mammals, and increase secreations of mineralocorticoids from the adrenal cortex (interrenal) in amphibians, repitles, and possibly in teleosts. Angiotensin causes glomerular diuresis in teleosts and lung-fishes, which may be ascribed to increased dorsal aortic pressure, while angiotensin may have both glomerular and tubular actions in some amphibians. Intracranial injection of angiotensin stimulates drinking in teleosts, repites, and birds, but not in amphibians. Hemorrage and acute hypotension are potent stimuli for causing renin release in an aglomerular teleost and a bird. When we consider this fact together with the anatomical evidence that the evolution of the JG cells precedes that of the macula densa, it appears that the RAS HAS EVOLVED WITH A CLOSE RELATIONSHIP TO BLOOD PRESSURE HOEMOSTASIS. On the other hand, there is no clear evidence that the RAS is activated in depleted teleosts and amphibians. Although the RAS appears to exert several functions in man and other mammals, some of them may be more important in primitive animals, while a similar function remains in mammals as a relic of the primitive system. Comparative approaches provide a perspective of biological history and unique experimental model that will eventually aid in understanding of the underlying mechanisms operating in mammals.

Binding and degradation of human 125I-HDL by rat adrenocortical cells

Abstract: In order to learn more about the mechanism by which high density lipoprotein (HDL) cholesterol is taken up by the adrenal cortex, binding and degradation of human 125I-HDL by suspensions of intact rat adrenal cortical cells have been examined. Cellular accumulation of 125I-HDL was found to occur in two phases. Our results indicate that the initial phase of association results from reversible binding of 125I-HDL to a specific saturable set of membrane binding sites. Binding site affinity appears equal for both rat and human HDL while affinity for human LDL is approximately one order of magnitude less on the basis of apoprotein weight. In addition, isolated rat adrenal cortical cells were found to degrade human 125I-HDL at a rapid rate. Degradation, like binding, can be prevented by addition of excess unlabeled HDL suggesting that binding and degradation are linked. Thus, one mechanism that could account for adrenal uptake of HDL cholesterol is endocytosis, initiated by lipoprotein binding to the HDL specific membrane binding site.

Activity of [Des-Aspartyl1]-Angiotensin II and Angiotensin II in Man: DIFFERENCES IN BLOOD PRESSURE AND ADRENOCORTICAL RESPONSES DURING NORMAL AND LOW SODIUM INTAKE

Abstract: This study was designed to compare the effect of [des-Aspartyl(1)]-angiotensin II ([des-Asp]-A II) and angiotensin II (A II) on blood pressure and aldosterone production in man under conditions of normal and low sodium (Na) intake. Seven normal male subjects in balance on constant normal Na intake (U(Na) V 160.3+/-5.0 meq/24 h) for 5 days received A II and [des-Asp]-A II infusions on two consecutive days; 1 mo later they were restudied after 5 days of low Na intake (U(Na) V 10.5+/-1.6 meq/24 h). Each dose was infused for 30 min, sequentially. During normal Na intake, [des-Asp]-A II from 2 to 18 pmol/kg per min increased mean blood pressure from 85.2+/-3 to 95.3+/-5 mm Hg and plasma aldosterone concentration from 5.2+/-1.1 to 14.3+/-1.9 ng/100 ml. During low Na intake, the same dose of [des-Asp]-A II increased mean blood pressure from 83.7+/-3 to 86.7+/-3 mm Hg and plasma aldosterone concentration from 34.4+/-6.0 to 51.0+/-8.2 ng/100 ml. In contrast, A II from 2 to 6 pmol/kg per min during normal Na intake increased mean blood pressure from 83.3+/-4 to 102.3+/-4 mm Hg and plasma aldosterone concentration from 7.0+/-2.2 to 26.8+/-2.0 ng/100 ml; during low Na intake, A II increased mean blood pressure from 83.0+/-3 to 96.0+/-4 mm Hg and plasma aldosterone concentration from 42.0+/-9.7 to 102.2+/-15.4 ng/100 ml. A II and [des-Asp]-A II were equally effective in suppressing renin release. Plasma cortisol and Na and K concentration did not change. The effects of two doses (2 and 6 pmol/kg per min) of each peptide on blood pressure and aldosterone production were evaluated. During normal Na intake, [des-Asp]-A II had 11-36% of the pressor activity and 15-30% of the steroidogenic activity of A II. Na deprivation attenuated the pressor response and sensitized the adrenal cortex to both peptides, but the increase in steroidogenesis was greater with [des-Asp]-A II than with A II. The dose-response curves for [des-Asp]-A II with respect to blood pressure and aldosterone production were not parallel, and although no maximum was established for A II, [des-Asp]-A II was less efficacious.In summary, (a) [des-Asp]-A II has biologic activity in man, (b) [des-Asp]-A II is less efficacious than A II in stimulating aldosterone production, (c) Na deprivation sensitizes the adrenal cortex more markedly to [des-Asp]-A II than A II, and (d) dose-response curves for the two peptides differ, suggesting the possibility that they act at different receptor sites in vascular smooth muscle and the adrenal cortex.

Schedule-induced polydipsia in rats: adrenocortical and hippocampal modulation.

Abstract: Onset of schedule-induced polydipsia (SIP) is related to adrenal gland weight. Adrenalectomy, but not demedullation, hastened the emergence of SIP, and exogenous corticosterone administration tended to reverse this effect. Hippocampal lesions were followed by a rapid and uniform release of SIP. None of the above manipulations influenced normal (home-cage) drinking. A synthesis of present findings with the literature suggests that the hippocampus and the adrenal cortex interact and that the equilibrium established within this system is reflected, for any particular rat, in its adjunctive behavior.

Preadolescent and adolescent endocrinology: physiology and physiopathology. II. Hormonal changes during abnormal pubertal development.

Abstract: • Based on the knowledge of the physiology of regulation of gonadotropins and gonadal steroids, basal levels of these hormones might be indicative of the etiologic factors of abnormal pubertal development. In addition, stimulatory tests may help in the diagnosis of such conditions. It is interesting that the pubertal maturation of the adrenal cortex is independent of the hypothalamic-pituitary-gonadal axis. The role of the adrenal cortex for the pubertal development remains questionable: adrenal androgens are low in isosexual precocious puberty, low in delayed adolescence, and normal in hyper- or hypogonadotropic hypogonadism. The importance of this role is doubled in congenital virilizing adrenal hyperplasia. When the disease is untreated, although adrenal androgens in excess advance bone age and hypothalamic maturation, girls remain prepubertal. When the therapeutic control is good, normal puberty occurs. The action of the adrenal androgens on growth and puberty remains to be determined. ( Am J Dis Child 132:797-805, 1978)

Cytogenesis in the rat adrenal cortex: evidence for an ACTH-induced centripetal cell migration from the zona glomerulosa.

Abstract: The mechanism underlying cytogenesis in the adrenal cortex of ACTH-treated rats was investigated. ACTH was found to increase the number of parenchymal cells in the zona fasciculata as well as that of "S" phase cells in the inner half of the zona glomerulosa and in the outer third of the zona fasciculata. The fate of 3H-thymidine labelled cells in ACTH-administered rats was also autoradiographically followed. The results are consistent with the hypothesis that the ACTH-provoked hyperplasia in the zona fasciculata involves the centripetal migration of newly-formed parenchymal cells from the zona glomerulosa.

Behavioural and pituitary-adrenal characteristics of pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane anesthesia. 2. Pituitary-adrenal function.

Abstract: Pituitary-adrenal function was investigated in two groups of Pietrain pigs differing by their susceptibility to the malignant hyperthermia syndrome induced by halothane, and in Large White pigs (LW). Plasma basal levels of glucocorticoids, measured by a protein binding technique, and plasma ACTH concentrations, determined by radioimmunoassay, did not differ according to halothane susceptibility but were higher in LW pigs compared with Pietrain pigs. The reactivity of the pituitary-adrenal axis to such stressors as exposition to a novel environment or shaking was the same for all experimental groups. The same was true concerning plasma levels of glucocorticoids and ACTH after injection of dexamethasone and response of the adrenal cortex to a standard dose of ACTH. These results demonstrate that LW pigs have a higher tonic secretion of ACTH than Pietrain pigs, but with identical phasic response to stimulations. Halothane susceptibility by itself appears to have no influence of pituitary-adrenal function.

Stress response and its relationship to cystic (pseudofollicular) change in the definitive cortex of the adrenal gland in stillborn infants.

Abstract: The adrenal glands of 41 fresh stillbirths were studied and a 'stress response' pattern could be seen in 28. In these glands the stress response was characterised by compact cell change, lipid depletion, excess pyroninophilia, and dilatation of the very prominent granular endoplasmic reticulum. Scattered areas of cytolysis of cells, especially of the definitive cortex, gave rise to the commonly seen cystic (pseudofollicular) change and it was obvious that cells undergoing lysis were severely 'stressed'. In 2 infants there was a 'clear cell reversal' pattern. Histological and ultrastructural changes of the stress response were not identified in 11. Infants of low birthweight score were somewhat more commonly represented in the group that did not show a stress response. Cytolytic changes accompanying a stress response were commoner in immature infants. It is argued that cystic (pseudofollicular) change in the adrenal cortex of the newborn signifies a previous stress reaction.

Effects of culture conditions on the growth and differentiation of transformed rat adrenocortical cells.

Abstract: Normal rat adrenocortical cells grow in vitro in two states of differentiation, depending on culture conditions. Under one set of conditions, they proliferate and are fibroblast shaped, with some myoid cell characteristics and with limited steroidogenic activity. Under alternate conditions they do not replicate and are epithelial-like and similar to adrenocortical secretory cells structurally and steroidogenically. The effects of oncogenic transformation on these cellular responses to culture variables were examined by using the Kirsten murine sarcoma virus-transformed rat adrenocortical line TRA. Transformation eliminated the differential proliferative response of the cells to culture variables and resulted in similar growth rates and high cell densities under all conditions. Horse serum, conducive to epithelial-like growth of nontransformed cells, caused aggregation, whereas fetal calf serum, conducive to fibroblastic growth of untransformed cells, caused dispersed growth in TRA cultures. Variations in dissociation procedures had little effect on growth patterns. Most ultrastructural characteristics of myoid as well as adrenocoritcal differentiation were reduced in TRA cells, although basement membranes and extracellular matrix were produced, but under different conditions than in untransformed cultures. Like normal adrenocortical cells, TRA cells were capable of 20alpha-reduction and delta5-3-beta-dehydrogenation of [4-14C5pregnenolone but, in contrast to untransformed cells, they did not respond to variables in culture conditions by qualitative changes in pregnenolone metabolism, did not produce deoxycorticosterone or corticosterone, and secreted progesterone, a hormone not recovered from untransformed cultures. TRA cells showed no increase in steroidogenic differentiation in response to those culture environment factors that normally cause modulation of the fibroblast-shaped adrenocortical stem cells to more differentiated steroid-secreting cells.

Effects of ACTH and 3',5'-cyclic purine nucleotides on the morphology and metabolism of normal adult human adrenocortical cells in primary tissue culture.

Abstract: Stereological studies showed that treatment of normal adult human adrenocortical cells in primary culture with ACTH or cyclic-AMP for 2 days results in similar increases in the volume of cells, of the mitochondrial and “membrane space” compartments and of the surface area of the smooth endoplasmic reticulum and mitochondrial cristae, and decrease in the lipid content of the cells. These changes were more marked after 8 days of treatment. Treatment for 2 days with cyclic-GMP had no striking effects on cell ultrastructure, whereas an 8-day treatment led to ultrastructural changes similar to those obtained after 2 days of ACTH-or cyclic-AMP-treatment. A discrete population of untreated cortical cells maintained a slow proliferation that was not effected by exposure to cyclic-GMP, but was significantly increased in cultures treated with ACTH or cyclic-AMP. Radioimmunological studies showed that untreated cortical cells kept secreting progesterone and cortisol and that ACTH, but neither cyclic nucleotide, increased the secretion rate per cell of both hormones. These results assign a major role to cyclic-AMP and a minor one to cyclic-GMP in the mediation of the differentiation-promoting and trophic effects, but not in the steroidogenic effects of ACTH on the human adrenal cortex.

Steroidogenesis in the Zones of the Mammalian Adrenal Cortex

Abstract: Publisher Summary This chapter describes steroidogenesis in the zones of the mammalian adrenal cortex By the microanatomy of the adrenal cortex, exemplified by those eutherian and metatherian species, it is clear that there are three major zones, namely, the zona glomerulosa, the zona fasciculata, and the zona reticularis with sub-divisions and additional zones Cells of organs are replaced throughout life, and the adrenal cortex is no exception; controversy lies in the mode whereby this is achieved Whatever may be the fact of the matter, the three zones produce various steroids in differing amounts and with both common and disparate controlling mechanisms The chapter discusses the receptor sites for ACTH and isolated cell studies It also discusses acute and chronic factors affecting secretion along with renin-angiotensin system, functional aspects of adrenocortical zonation, metatheria, adrenocortical sex steroids, and gonadotrophins

An ultrastructural, morphometric and autoradiographic study of the effects of 7,12-dimethylbenzanthracene on the rat adrenal cortex

Abstract: The effects of chronic treatment (up to 9 consecutive days) with 7,12-dimethylbenzanthracene (DMBA) on the adrenal glands of adult male Wistar rats were investigated. Morphometry showed that DMBA provokes atrophy of the zona reticularis which was due to the decrease in both cell volume and number. The zona fasciculata showed only a decrease in the cell volume, whereas the zona glomerulosa did not display any significant changes. Autoradiography demonstrated that DMBA induces a significant increase in the number of mitoses and “S” phase cells in the zona glomerulosa and outer zona fasciculata, which may be interpreted as a repair mechanism of the DMBA-provoked slight necrosis in the inner adrenocortical layers. The mechanism(s) underlying the cytotoxic effect of DMBA is discussed in the light of our ultrastructural observations showing that the chemical causes a decrease in the volume of the mitochondrial and nuclear compartments and in the surface of smooth endoplasmic reticulum as well as an increase in the volume of the lipid compartment.

A histochemical study on the effects of photoperiod on gonadal and adrenal function in the male bank vole (Clethrionomys glareolus).

Abstract: NADH- and NADPH-diaphorases, 3alpha-, delta5-3beta-, 11beta- and 17beta-hydroxy-steroid dehydrogenases (HSD) and lipids were studied histochemically in the testes and adrenals of male bank voles kept in a long (16L:8D) or a short (8L:16D) photoperiod (Groups L and S, respectively). At 67 days of age the Group L males were heavier and had active and significantly larger testes than Group S males. The testes of Group S males were regressed and were also significantly smaller than those of 18-day-old animals born and reared in a 18L:6D photoperiod. Lipid droplets were detected in the Leydig cells and intratubular spaces in the testes of Group L animals, but were absent from those of Group S voles. The adrenal cortex of the Group L animals was virtually devoid of lipids, but large lipid inclusions were present in the basal zona fasciculata of the Group S voles. In the Group L testes the diaphorase activities were more intense and the difference in enzymic activity between the seminiferous epithelium and the Leydig cells was more pronounced (especially for NADH-diaphorase) than that in the testes of Group S animals. Moreover, the 3alpha-- and delta5-3beta-HSD activities were much stronger in the testes of sexually active animals; 17beta-HSD activity was present in the Leydig cells of the active testes, and absent in the regressed testes. There was no marked difference between the two groups of animals with regard to the distribution or intensity of diaphorases, 3alpha-, delta5-3beta-, 11beta- or 17beta-HSD in the adrenal cortex. It is concluded that a decline in steroid synthesis occurs in the testes of voles kept in a short photoperiod. The large lipid inclusions observed in the adrenal cortex of such animals suggest decreased corticosteroid synthesis and/or secretion.