Megaoesophagus in a patient with autoimmune polyglandular syndrome type II

Dysphagia and vomiting are frequently present in untreated Addison's disease. These non-specific symptoms may be due either to the metabolic disorder and myopathy or to disorders associated with Addison's disease. We describe a patient with autoimmune adrenal failure as a feature of autoimmune polyglandular syndrome (APS) type II. This patient was referred initially because of megaoesophagus. The association of megaoesophagus with Addison's disease or any of the three types of APS has not previously been described in humans. The association of megaoesophagus and adrenal failure, however, is known to occur in Allgrove's syndrome, a disease with primary manifestation in childhood characterized by adrenal failure, achalasia and alacrimia. Moreover, there are several reports on the association of megaoesophagus with adrenocortical insufficiency and other autoimmune endocrine diseases in dogs. Vomiting and dysphagia usually resolve with hormone substitution in patients with isolated Addison's disease. In our patient these symptoms disappeared in spite of the radiological persistence of megaoesophagus, which might have been overlooked if the diagnosis of Addison's disease had been made earlier. The occurrence of megaoesophagus might be more common than previously suspected and we suggest a systematic search for similar findings in other patients with autoimmune Addison's disease, even when minor dysphagia is present.

Functional aspects of the effect of prolactin (PRL) on adrenal steroidogenesis and distribution of the PRL receptor in the human adrenal gland

Hyperprolactinemia is one of the most common disorders in endocrinology. A role for PRL on the human adrenal gland has been postulated in various clinical studies. We have demonstrated for the first time the expression of the PRL receptor in the human adrenal gland and in human adrenal primary cell cultures using PCR and immunohistochemical methods. Using immunostaining, we could detect the PRL receptor in all three zones of the adrenal cortex. Only weak staining was observed in the adrenal medulla. The influence of PRL on the secretion of cortisol, aldosterone, and androgens in human primary cell cultures was investigated. After stimulation with PRL (10(-7) mol/L), we measured increased concentrations of cortisol (155 +/- 9.8%; P < 0.005%), aldosterone (122 +/- 3.7%; P < 0.005), and dehydroepiandrosterone (121 +/- 8.6%; P < 0.05) in the cell supernatant. PRL did not affect the expression of messenger ribonucleic acid of cytochrome P45017 alpha in human adrenal cell cultures. In conclusion, we found the PRL receptor in the human adrenal gland. We postulate that PRL has a direct effect on adrenal steroidogenesis, thereby regulating adrenal function, which may be of particular relevance in clinical disorders with hyperprolactinemia.

Ultrastructural dynamics of mitochondrial morphology in varying functional forms of human adrenal cortical adenoma

Adrenal cortical mitochondria display an extensive capacity to adapt morphologically to the functional state of the adrenal cortical cell. In the present study, we have used transmission electron microscopy to analyze cortical tissues from 3 normal human adrenal glands (zona fasciculata and zona glomerulosa), and from 8 steroid-secreting adrenal cortical adenomas (3 cortisol-producing, 4 aldosterone-producing, and 1 progesterone-producing tumor), correlating both clinical and biochemical features with cellular ultrastructure. The morphology of mitochondria was related to the enzyme activity and steroid-biosynthetic capacity of each tumor. Cells from aldosterone-producing adenomas demonstrated a large number of elongated tubular mitochondria with characteristic bridging of inner membranes, producing a lamellar-type pattern. Cells from cortisol-producing adenomas showed large round mitochondria with vesicular or tubulovesicular inner membranes surrounded by a characteristic dilated smooth endoplasmic reticulum. A highly unusual progesterone-producing adenoma, in which a deficiency of 21 alpha-hydroxylase activity was demonstrated, showed a peculiar type of enlarged lamellar mitochondria with bright inner matrix and a reduced number of inner membranes. Therefore, the ultrastructural characteristics of adrenal cortical mitochondria appear to be potential markers for the differentiation of steroid-producing adenomas. These studies point to the possibility of a broader use of electron microscopy in the study of adrenal tumors.

Human adrenal cells express tumor necrosis factor-alpha messenger ribonucleic acid: evidence for paracrine control of adrenal function

Tumor necrosis factor (TNF) is gaining increasing importance in clinical medicine. It plays a role in the interaction of the immune system with the hypothalamic-pituitary-adrenal axis. In the present study various morphological methods, including immunohistochemistry, electron microscopy, and in situ hybridization were applied to characterize the localization and distribution of TNF in the human adrenal gland. Double immunostaining revealed an astonishing degree of intermingling of steroid-producing cells and chromaffin cells. Macrophages could be found in all regions of the adrenal gland, but particularly in the transition zone of cortex and medulla. The steroid-producing cells of the inner zone of the cortex express major histocompatibility complex class II molecules. On the ultrastructural level, immune cells, steroid cells, and catecholamine-producing cells were found in direct contact. The combination of immunohistochemistry and in situ hybridization was optimally suited to define the exact cellular source of TNF in the human adrenal. TNF is produced in macrophages, but above all in 17 alpha-hydroxylase-positive cells (steroid-producing cells) in the zona reticularis and medulla. No signal was found in chromaffin cells. TNF may induce major histocompatibility complex class II in human adrenal gland in a paracrine or autocrine manner. It is concluded that TNF may have an important role in normal human adrenal physiology.

Angiotensin II regulates both adrenocortical and adrenomedullary function in isolated perfused pig adrenals

The effect of angiotensin II (ANG II) on all four zones of the adrenal gland was studied in preparations of isolated perfused porcine adrenals. The experimental design offered the possibility to analyze directly the actions of ANG II while preserving the structure of the gland. ANG II stimulated aldosterone, cortisol, and androstenedione release in a dose-dependent manner. At a final ANG II concentration of 10(-8) M aldosterone increased from 0.7 +/- 0.05 to 3.4 +/- 0.9 ng/ml, cortisol from 50 +/- 5 to 430 +/- 60 micrograms/l, and androstenedione from 1.4 +/- 0.2 to 4.4 +/- 0.8 ng/ml. In addition, ANG II provoked a release of adrenaline from 4.1 +/- 0.6 to 27.5 +/- 0.5 micrograms/ml and of noradrenaline from 5.5 +/- 1.1 to 36.0 +/- 8.7 micrograms/ml. Our results show that secretion of both adrenocortical steroids and adrenomedullary catecholamines can be evoked by ANG II. ANG II seems to influence not only the function of the zona glomerulosa but the function of the entire adrenal gland.

Long-term effect of octreotide in acromegaly on insulin resistance

An important feature of acromegaly is a reduced action of insulin on hepatic gluconeogenesis and peripheral glucosal disposal. Octreotide (SMS) exerts complex effects on hormonal and metabolic regulations affecting glucose homeostasis. Eight patients with active acromegaly despite surgical intervention (age 44.8 +/- 3.5 years, BMI 27.3 +/- 1.6 kg/m2, lean body mass (LBM) 70 +/- 3.2%, blood glucose 5.24 +/- 0.26 mmol/l, HbA1c < or = 6.5%) were investigated before and after 6 months of treatment with SMS in an open trial. SMS was injected sc. at a dosage between 100-200 micrograms t.i.d. Mean GH and IGF1 levels during SMS therapy were significantly reduced (GH 9.6 +/- 1.9 ng/ml vs. 4.9 +/- 1.3 ng/ml, p < 0.05; IGF1 729.5 +/- 84 ng/ml vs. 415 +/- 49 ng/ml, p < 0.05). OGTT and euglycaemic-clamp-studies were performed before and after 6 months of SMS treatment. The glucosal disposal rate on average (insulin infusion rate 40 mU/m2/min) was not significantly changed following SMS treatment (McLBM before 3.60 +/- 0.38, after 3.95 +/- 0.41 mg/kg LBM/min). There was a positive correlation (r = 0.620) between the individual change of IGF1 and the change of McLBM. Additionally there was no significant difference of serum basal insulin levels (0.19 +/- 0.01 vs. 0.23 +/- 0.06 nmol/l) as well as basal C-peptide levels (0.79 +/- 0.07 vs. 0.47 +/- 0.04 nmol/l) before and with SMS treatment. We therefore conclude that long-term treatment of acromegalic patients with SMS, which achieves a successful reduction of GH and IGF1 levels, does not always guarantee a significant improvement in glucose metabolism.(ABSTRACT TRUNCATED AT 250 WORDS)

Plasma catecholamines in patients with Addison's disease

BACKGROUND AND OBJECTIVE

Two endocrine tissues are present within the adrenal gland: the steroid producing cortical cells and the catecholamine producing chromaffin cells. Glucocorticoids occur in high concentrations in the adrenal medulla. In vitro, glucocorticoids have been shown to induce the enzyme phenyl-N-methyl-transferase which is necessary for the production of adrenaline in adrenal medullary cells. The purpose of this study was to evaluate the possible significance of a local glucocorticoid effect on adrenomedullary function.

DESIGN

Plasma catecholamine levels were measured in patients with autoimmune Addison's disease where local production of corticosteroids is deficient in the presence of intact chromaffin tissue.

MEASUREMENTS

Catecholamines were measured by high pressure liquid chromatography and ACTH, renin and adrenal steroids by radioimmunoassay.

PATIENTS

Nineteen Addisonian patients (9 females, 10 males) were treated according to a standard regime with oral cortisone acetate (37.5 mg/day) and fludrocortisone (0.1 mg/day). All patients were clinically well.

RESULTS

Mean plasma adrenaline in patients with Addison's disease was significantly reduced compared to a sex and age matched control group (males (n = 10) 143 +/- 36 pmol/l, controls (n = 27) 303 +/- 30 pmol/l, P < 0.01; females (n = 9) 77 +/- 25 pmol/l, controls (n = 27) 293 +/- 21 pmol, P < 0.001). The noradrenaline:adrenaline ratio was clearly higher in patients with Addison's disease (males 24 +/- 4, controls 9 +/- 1, P < 0.01; females 45 +/- 6, controls 9 +/- 1, P < 0.01).

CONCLUSION

We conclude that the physiologically high local glucocorticoid concentration may be responsible for normal adrenaline production under basal conditions.

Sympathoadrenal regulation of adrenocortical steroidogenesis

Sympathoadrenal regulation of adrenocortical steroidogenesis was studied on a physiological, cellular, molecular and morphological level. The effects of nerve activation and of epinephrine (EPI) on adrenal corticosteroid release were compared in isolated perfused pig adrenals with preserved nerve supply. Splanchnic nerve activation as well as perfusion with EPI provoked a significant release of cortisol, aldosterone and androstenedione. In cultured bovine adrenocortical cells steroid secretion and accumulation of P450scc, P450(17) alpha, P450c21 and P450(11) beta mRNAs were studied after stimulation with EPI with or without propranolol or phentolamine. Incubation with EPI stimulated steroidogenesis and increased the levels of all four P450-mRNAs. The beta-adrenergic antagonist propranolol totally blocked the effects of EPI while the alpha-antagonist phentolamine had no effect. Using immunohistochemistry, adrenals were studied morphologically. The contact zones of the two cell types were investigated on an electron microscopical level. Cortical and medullary cells were closely interwoven with cortical and chromaffin cells in direct apposition, providing the possibility for paracrine interactions. It is concluded that the release of corticosteroids can be stimulated through the sympatho-adrenal system. The stimulatory action of EPI upon adrenal steroid formation and accumulation of all four P450-mRNAs requires beta-adrenergic receptors. Taking into consideration the close colocalization of cortical and medullary tissue, this stimulation may be mediated by chromaffin cells in a paracrine manner.

IL-1 is expressed in human adrenal gland in vivo. Possible role in a local immune-adrenal axis

IL-1 is an important mediator in the dialogue between the immune system and the hypothalamo-pituitary-adrenal axis. A direct influence of IL-1 upon adrenal steroidogenesis has been demonstrated in experimental animals. We therefore designed a study to see if IL-1 is expressed within the normal human adrenal gland. The combination of in situ hybridization and specific immunostaining to IL-1 beta was eminently suited to demonstrate both mRNA and protein production. The specific immunostaining of the different cells combined with in situ hybridization (IL-1) allowed us to identify the exact cellular source of IL-1. IL-1 mRNA occurred in the zona reticularis in 17 alpha-hydroxylase positive steroid cells surrounding the adrenomedullary cells. Some CD68+ macrophages in this zona showed a positive signal. A weak signal was seen to IL-1 mRNA in few chromaffin cells, while IL-1-like immunoreactivity was more frequent. We conclude that in the normal situation in man IL-1 is mainly expressed in specialized cortical cells. The occurrence of the major glucocorticoid inducing factor in the normal human adrenal gland itself provides evidence for an autocrine or paracrine reaction under physiological conditions.

Interleukin-6 messenger ribonucleic acid expression in human adrenal gland in vivo: new clue to a paracrine or autocrine regulation of adrenal function

Interleukin-6 (IL-6) is an important mediator in the interaction of the hypothalamo-pituitary-adrenal axis with the immune system. Recently, a direct influence of IL-6 on adrenal steroidogenesis has been demonstrated. Therefore, we designed a study to determine whether IL-6 is expressed within the normal human adrenal gland. The combination of in situ hybridization and specific immunostaining was eminently suited to identify the cell types producing IL-6. IL-6 messenger ribonucleic acid occurred in the inner zone of the adrenal cortex in anti-17 alpha-hydroxylase-positive steroid cells. Also, CD68-positive macrophages in the zona reticularis showed a positive signal. No reaction was seen in chromaffin cells. We conclude that under normal conditions, IL-6 is expressed in specialized adrenocortical cells. Therefore, IL-6 may play an important role as a paracrine or autocrine factor in a local immune-adrenal interaction.

Macrophages within the human adrenal gland

There is increasing evidence for an immune-adrenal interaction in which macrophages may play an important role. However, few data are available with respect to a human intra-adrenal macrophage system. In this study, we have investigated the density, distribution and phenotype of human adrenal macrophages using monoclonal antibodies. Macrophages are localized in all zones of the adrenal gland. These cells exhibit the phenotype of the phagocytotic macrophage compartment (CD11c+, KiM8+). At the ultrastructural level, macrophages are frequently attached to the endothelial wall, but also lie in direct contact with cortical and chromaffin cells. This investigation reveals the cellular basis for the possible role of macrophages in the local immune-neuroendocrine axis.

Interleukin-6 stimulates the hypothalamus-pituitary-adrenocortical axis in man

A recent study in humans, animal studies, and in vitro data have suggested that interleukin-6 (IL-6) stimulates the secretory activity of the hypothalamus-pituitary-adrenocortical (HPA) axis. In a phase II study, one female and six male patients with metastatic renal cell carcinoma received IL-6 to evaluate a possible antitumor effect of IL-6. This offered the possibility of investigating the influence of IL-6 on the HPA axis in man. The subjects were studied 1 day before, on day 1, and on day 21 of IL-6 therapy (150 micrograms administered sc every day at 0900 h). Blood samples were taken at 0900, 1100, 1300, 1600, and 2000 h the day before, on day 1 of IL-6 therapy, 24 h after the first IL-6 injection, and on day 21 of IL-6 treatment. Plasma ACTH and cortisol levels promptly followed the rise of IL-6, which peaked 4 h after administration. They were significantly (P < 0.05) higher at 1100 and 1300 h on day 1 of IL-6 therapy compared with the corresponding plasma levels the day before IL-6 treatment. Cortisol concentrations remained significantly increased at 1600 and 2000 h after IL-6 administration. Twenty-four hours after the first IL-6 administration, IL-6, ACTH, and cortisol levels had reached preinjection values. Although plasma cortisol levels were similar on days 1 and 21, ACTH levels were lower on day 21 (than on day 1), but significantly elevated at 1100 h compared with levels on the day before the first IL-6 injection. Results confirming the very recent data of another study demonstrate a stimulating effect of IL-6 on the HPA axis in man. They support the notion that IL-6 is one of the cytokines involved in the interaction between the immune system and the HPA axis.

Interleukin-1 regulates corticosterone secretion from the rat adrenal gland through a catecholamine-dependent and prostaglandin E2-independent mechanism

Studies from this and other laboratories have shown that interleukin-1 alpha (IL-1 alpha) stimulates corticosterone and prostaglandin (PG) release from primary cultures of rat adrenal cells. A previous report from our laboratory (1) indicated involvement of the alpha-adrenergic system in IL-1 alpha-stimulated corticosterone secretion from primary cultures of rat adrenal cells. The present experiments were conducted to determine the role of catecholamines and eicosanoids in IL-1-stimulated corticosterone release from primary rat adrenal cells. Primary adrenal cells were incubated for 24 h at 37 C with IL-1 alpha (10 nM), medium, or the appropriate agonist. After incubation, the supernatant was removed and assayed for epinephrine, prostaglandin E2 (PGE2), and corticosterone concentrations. At this time, untreated adrenal cells were fixed for immunohistochemical staining with a specific antirat tyrosine hydroxylase antibody. The results indicate that the primary adrenal cells contained 3.1 +/- 0.45% tyrosine hydroxylase-positive cells. On the ultrastructural level, the chromaffin cells were found to be in direct cellular contact with cortical cells. IL-1 alpha significantly increased (P < 0.05) epinephrine, PGE2, and corticosterone levels above those in medium-treated controls from primary adrenal cells. In the presence of the alpha-adrenergic antagonist phentolamine (10 microM), IL-1 alpha-stimulated (P < 0.05) corticosterone release was inhibited, whereas IL-1 alpha-induced PGE2 release was not affected. Conversely, the presence of the cyclooxygenase inhibitor indomethacin (10 microM) significantly inhibited IL-1 alpha-induced PGE2 secretion without altering the effect of IL-1 alpha on corticosterone release. Inhibitors of the 5-lipoxygenase system (10 microM CGS 8518) and the lipoxygenase and cytochrome P450 monooxygenase systems (10 microM nordihydroguaiaretic acid) did not effect IL-1 alpha-induced corticosterone or PGE2 release. These observations indicate that IL-1 alpha stimulates corticosterone release through an alpha-adrenergic mechanism that is independent of PGE2 release from primary rat adrenal cells.

Sympathoadrenal regulation of adrenal androstenedione release

The effects of epinephrine and of splanchnic nerve activation on adrenocortical androstenedione release were studied in intact isolated perfused pig adrenals with preserved nerve supply. In addition, long-term effects of epinephrine were characterized in bovine adrenocortical cells in primary culture. To investigate the contact zones of the androgen-producing cells of the zona reticularis with the catecholamine producing cells of the adrenal medulla, cortical cells were immunostained for cytochrome P450 side chain cleavage (P450SCC). Perfusion of the isolated adrenals with epinephrine (10(-7) to 10(-5) M) stimulated androstenedione release in a dose-dependent manner. At a concentration of 10(-6) M, epinephrine provoked an increase to 179.11 +/- 16.14% of basal secretion (p < 0.05). Electrical stimulation of the splanchnic nerves led to an increase to 151.5 +/- 9.24% of basal values (p < 0.05). Epinephrine (10(-6) M) reached 40% and activation of the splanchnic nerves 26% of the stimulatory effect of ACTH at a physiological concentration (10(-10) M). The alpha-agonist phenylephrine had no effect on androstenedione release. In cell cultures, epinephrine stimulated the release of androstenedione in a dose-dependent manner with an ED50 of 0.75 x 10(-6) M. The maximal effect was reached at 10(-5) M with 8.92 +/- 0.66 pmol androstenedione/dish/24 h; the basal secretion was 1.44 +/- 0.54 pmol/dish/24 h. The epinephrine-stimulated androstenedione release was abolished by the beta-adrenergic antagonist propranolol while the alpha-adrenergic antagonist phentolamine had no effect. Immunohistochemical staining of paraffin sections of bovine and porcine adrenals for P450SCC revealed that zona reticularis and zona medullaris are closely interwoven.(ABSTRACT TRUNCATED AT 250 WORDS)

Intimate contact of chromaffin and cortical cells within the human adrenal gland forms the cellular basis for important intraadrenal interactions

A new role for the adrenal medulla as a regulator of adrenocortical function has been postulated. However, there has been no idea as to how such a cellular interaction within the human adrenal gland could take place. In this study we were able to demonstrate with the help of specific immunostaining of cortical and chromaffin cells, respectively, that the two endocrine systems are interwoven with each other to an astonishing degree. Protrusions, clusters, islets, and single cortical cells were made visible by immunostaining with an antibody against 17 alpha-hydroxylase cytochrome P450 enzyme. They occurred diffusely within the entire adrenal medulla, providing ample contact zones for paracrine interactions. Specific immunostaining for the neuroendocrine protein chromogranin-A identified the occurrence of chromaffin cells within all three zones of the human adrenal cortex, including the zona glomerulosa. In an ultrastructural analysis, cortical and chromaffin cells were found in all zones in direct apposition, providing the possibility for direct intercellular exchange. The close morphological colocalization of cortical and chromaffin cells revealed in this study may constitute the basis for the growing evidence of relevant intraadrenal paracrine mechanisms within the human adrenal gland.

Vasoactive intestinal peptide (VIP) stimulates androstenedione release in isolated perfused pig adrenals

The effect of the vasoactive intestinal peptide (VIP) on adrenal androstenedione release was investigated in isolated perfused pig adrenals. Our system allowed a direct comparison with the effect of ACTH, gonadotropins and proopiomelanocortin 79-96, which has been suggested to be the specific cortical androgen stimulating hormone (CASH). VIP 10(-8) M provoked a threefold increase of androstenedione release which was similar to the effect of ACTH at a physiological concentration of 10(-10) M. Gonadotropins at a perfusate concentration of 0.5 I.U. weakly but significantly increased androstenedione output, the response amounting to 32% of that elicited by ACTH or VIP. Perfusion of the adrenals with CASH at concentrations of 10(-11) to 10(-8) M did not affect the release of adrenal androstenedione. VIP appears to be a modulator of adrenal androgen release which might be involved in a local neuroendocrine control of adrenal androgen secretion.

Ultrastructural evidence for a paracrine regulation of the rat adrenal cortex mediated by the local release of catecholamines from chromaffin cells

The adrenal glands of perfusion fixed rats were investigated by light and electron microscopy. Within the rat adrenal cortex occurred rays and islets of chromaffin cells which were in close contacts with cortical cells on the electron microscopical level. We achieved to catch the process of exocytosis from a chromaffin cell located within the zona glomerulosa in direct apposition with an adrenocortical cell. The documentation of an exocytotic process from a chromaffin cell neighbouring a cortical cell provides direct evidence in support of a paracrine regulation of the cortex mediated by chromaffin cells.

Regulation of adrenal steroidogenesis by adrenaline: expression of cytochrome P450 genes

The effect of adrenaline on the secretion of cortisol and cyclic AMP (cAMP) and on the accumulation of four different mRNAs encoding cholesterol side-chain cleavage cytochrome P450 (P450scc), 17 alpha-hydroxylase cytochrome P450 (P450(17 alpha)), 21-hydroxylase cytochrome P450 (P450c21) and 11 beta-hydroxylase cytochrome P450 (P450(11 beta)) was studied in bovine adrenocortical cells in primary culture and compared with the effects of ACTH. Treatment of cultured cells with adrenaline (1-100 mumol/l) showed a biphasic response in cortisol release over 1-24 h. Concentration of cAMP in the culture media increased from a basal level of < 0.06 pmol/dish to a maximal level of 40.14 +/- 8.9 pmol/dish with a half-maximal release of 20.07 pmol cAMP/dish in the medium reached 1.2 h after treatment with 10 mumol adrenaline/l. This stimulation resulted in an uniform increase in the levels of all four P450 mRNAs as revealed by Northern blot analysis. Increasing doses of adrenaline produced a maximal mRNA accumulation at a concentration of 10 mumol adrenaline/l. Incubation of the cells with 10 mumol adrenaline/l for 1-24 h produced a biphasic time-course with a half-maximal stimulation after about 5-6 h. Maximal stimulation with ACTH (100 nmol/l) caused different accumulations of the four mRNAs: P450sec mRNA increased twice as much and P450(17 alpha) mRNA six times as much as the accumulation of P450c21 mRNA and P450(11 beta) mRNA, which was about ten-fold over basal values. Propranolol totally blocked the stimulatory effect of adrenaline but not the effect of ACTH.(ABSTRACT TRUNCATED AT 250 WORDS)

Structure and dynamics of adrenal mitochondria following stimulation with corticotropin releasing hormone

The mitochondria of rat adrenals were investigated qualitatively and quantitatively in different functional states of the adrenal cortex. Following stimulation of the animals with corticotropin releasing hormone (CRH), the corticosterone serum levels reached a maximum 1 hour after stimulation with CRH. The amount of inner mitochondrial membrane within the zona fasciculata increased showing a biphasic time course, with a first maximum 2 hours and a second maximum 8 hours after stimulation. In contrast, a significant rise of mitochondrial volume occurred only 24 hours after CRH stimulation. Therefore, the dense vesicularization of mitochondrial cristae may constitute an early process to enhance the steroidogenic capacity of these cells. Within cells of the transition zone between zona glomerulosa and zona fasciculata, we could depict a special type of mitochondria with characteristic crescent-like cristae only seen after stimulation with CRH. This type of mitochondria may represent an intermediate form between mitochondria of zona glomerulosa and zona fasciculata underlining the impressive transformational capacity of adrenocortical mitochondria. After hypophysectomy, zona fasciculata cells contained mitochondria with tubular inner membranes, representing a hypofunctional state. In contrast, the hypofunctional state after hypophysectomy and the hyperfunctional state after stimulation of the adrenal cortex via CRH injection did not appear to correlate with the morphology of mitochondria from the zona reticularis and adrenal medulla.

Role of ovarian sex steroids in the regulation of thyrotropin (TSH) secretion of hypogonadal women

The exact role of ovarian sex steroids in the neuroendocrine regulation of thyrotropin (TSH) release in women can only be accurately assessed in the absence of any considerable ovarian sex steroid feedback upon the hypothalamic-pituitary unit. Consequently, the unstimulated episodic and thyrotropin-releasing hormone (TRH) stimulated TSH secretion was evaluated in postmenopausal women before and during sequential ovarian sex steroid replacements. Seven euthyroid women (mean age: 59.4 years) were studied initially without any sex steroid replacement (control studies), then on the last day of a 21-day course of oral estradiol-valeriate (E2) administration (2 mg daily) and finally, on the last day of a 21-day course of oral estradiol-progesterone (E2/P4) replacement (2 mg E2 and 200 mg micronized P4 daily). During all study occasions, blood was sampled at 10 min intervals for 10 h, while TRH (200 micrograms iv) was administered 8 h after initiation of blood collections. Compared to the control conditions, serum E2 and P4 concentrations markedly increased (p less than 0.001) following oral E2 or E2/P4 treatments. Total triiodothyronine (T3) and thyroxine (T4) concentrations and free T3 and T4 equivalents remained unchanged during E2 and E2/P4 regimens. In the unstimulated secretory profiles, TSH was found to be episodically released, with little interindividual variability for each study condition. Since the TSH pulse attributes (pulse amplitudes, frequencies, interpulse intervals, mean TSH concentrations, by Cluster pulse algorithm) did not significantly change during E2 and E2/P4 replacements, the episodic character of TSH secretion virtually remained unchanged by sex steroid replacements.(ABSTRACT TRUNCATED AT 250 WORDS)

Role of the vasoactive intestinal peptide in a neuroendocrine regulation of the adrenal cortex

Using a method for isolation and perfusion of pig adrenal glands with preserved nerve supply, we measured the release of cortisol and aldosterone and of the vasoactive intestinal peptide (VIP) after electrical stimulation of the splanchnic nerves. Additionally, the effect of VIP (at final concentrations of 10(-10)-10(-7) M) in the perfusion medium on the release of cortisol and aldosterone was investigated. The amount of VIP contained within the adrenal was measured by chromatography, and the localization of VIP in the adrenal gland was investigated immunohistochemically. Stimulation of the splanchnic nerves provoked a significant release of VIP (2.7- to 17-fold) and of the corticosteroids cortisol (2.5- to 6.7-fold) and aldosterone (1.6- to 2.8-fold). VIP added to the perfusion medium stimulated secretion of both corticosteroids with a maximal effect at 10(-8) M. Cortisol release increased 20- to 58.5-fold over basal, aldosterone release increased 2.9- to 4.9-fold over basal. This VIP-stimulated release had the same range of magnitude as the release stimulated by adrenocorticotropic hormone in physiological concentrations (10(-10) M). The mean concentration of VIP-like immunoreactivity in the adrenal glands was 8.9 +/- 2.1 pmol/g wet weight. Immunohistochemical investigations showed immunoreactive cells within the adrenal medulla as well as VIP-ergic nerve fibers in the cortex of the adrenal gland. These data show that the adrenal cortex can be stimulated independent of the hypothalamus-pituitary-adrenal axis via a neuroadrenocortical axis. In this regulatory pathway, the VIP-ergic innervation of the adrenal cortex may be a potent stimulatory element.

Adrenaline stimulates cholesterol side-chain cleavage cytochrome P450 mRNA accumulation in bovine adrenocortical cells

The effect of adrenaline on the accumulation of mRNA encoding cholesterol side-chain cleavage cytochrome P450 (P450scc) and cortisol secretion was studied in bovine adrenocortical cells in primary culture. Treatment of cultured cells with adrenaline resulted in a 2-fold increase in mRNA encoding P-450scc, as revealed by Northern blot analysis. Under these conditions the maximal stimulation with ACTH resulted in a 6-fold accumulation of mRNA encoding P450scc. The effect of adrenaline on the expression of P450scc was abolished by the beta-blocker propranolol, while propranolol had no effect on ACTH-induced P450scc mRNA accumulation. Adrenaline stimulated the secretion of cortisol in a dose-dependent manner with a median effective dose of 0.5 mumol/l. The adrenaline-stimulated cortisol secretion amounted to 42% of the effect of ACTH (0.1 nmol/l). Upon adrenaline treatment, cAMP concentration in the culture medium increased about 50-fold over the basal value. It is concluded that the stimulatory action of adrenaline upon cortisol formation requires beta-adrenergic receptors and is due, at least in part, to a cAMP-mediated increases in the accumulation of mRNA encoding P450scc.

Morphological and hormonal changes following vasectomy in rats, suggesting a functional role for Leydig-cell associated macrophages

The effects of bilateral vasectomy on hormone serum levels as well as Leydig cell and associated macrophage structure were analysed in parallel in rats 36 weeks following the operation. Serum testosterone was decreased in vasectomized rats (1.96 +/- 0.11 ng/ml) compared with control animals (3.44 +/- 0.22 ng/ml, p less than 0.05). Vasectomy also resulted in an increase in serum luteinizing hormone (LH) to 0.299 +/- 0.02 ng/ml compared to the control group (0.175 +/- 0.01 ng/ml, p less than 0.05). Also serum follicle-stimulating hormone (FSH) was increased following vasectomy (350.88 +/- 15.5 ng/ml) compared to 132.0 +/- 4.8 ng/ml in control animals (p less than 0.01). Morphometric analysis of Leydig cells showed hypertrophy with a 19% increase of total cell area, p less than 0.01 (cytoplasm 28%, nucleus 8% increase). On the ultrastructural level, leydig cells demonstrated massively dilated smooth endoplasmic reticulum characteristic for stimulated cells. There was also a significant hypertrophy of the Leydig cell-associated macrophages. The macrophage cell area was enlarged by 22%, p less than 0.01 (cytoplasm 25%, nucleus 18%). Vasectomy also led to remarkable ultrastructural changes of macrophages with a marked dilated and extended rough endoplasmic reticulum. Macrophages were found in apposition to Leydig cells with close cellular contact zones, and they frequently formed cell extensions on Leydig cells. Our data obtained following vasectomy indicate that, by their close contacts to Leydig cells, as well as the known influence on Leydig-cell steroidogenesis, macrophages may form the basis of a local immunoendocrine regulation of the pituitary-gonadal axis.

Ultrastructural evidence for cortico-chromaffin hybrid cells in rat adrenals?

The adrenals of perfusion fixed rats were investigated by electron microscopy. In 2 out of 12 animals studied, chromaffin cells were detected that contained organelles identical to adrenocortical mitochondria and smooth endoplasmic reticulum. The mitochondria were round-shaped with the vesicular cristae typical for steroid hormone producing cells. They were located within the cytoplasm of adrenomedullary cells neighbouring chromaffin vesicles, rough endoplasmic reticulum and the characteristic elongated mitochondria of chromaffin cells with laminar cristae. The mitochondria-like structures could be clearly differentiated from the extracellularly located synaptic endings. It can therefore be concluded that some rare cortico-chromaffin hybrid cells or chromaffin cells that present a mitochondrial-endoplasmic system of adrenocortical cells exist within the adrenal medulla. This surprising finding may offer an explanation for the long line of inconsistencies in clinico-pathological reports of adrenal morphology.

Morphological evidence for a close interaction of chromaffin cells with cortical cells within the adrenal gland

The adrenal medulla appears to exert a regulatory influence on adrenocortical steroidogenesis. We have therefore studied the morphology of rat, porcine and bovine adrenals in order to characterize the contact zones of adrenomedullary and adrenocortical tissues. The distribution of chromaffin cells located within the adrenal cortex and of cortical cells located within the adrenal medulla was investigated. Chromaffin cells were characterized by immunostaining for synaptophysin and chromogranin A, both being considered specific for neuroendocrine cells. Cortical cells were characterized by immunostaining for 17 alpha-hydroxylase, an enzyme of the steroid pathway. Cellular contacts of chromaffin cells and cortical cells were examined at the electron microscopical level. In rat and porcine adrenals, rays of chromaffin cells, small cell clusters and single chromaffin cells or small invaginations from the medulla could be detected in all three zones of the cortex. Chromaffin cells often spread in the subcapsular space of the zona glomerulosa. In porcine and bovine adrenals, 17 alpha-hydroxylase immunoreactive cells were localized within the medulla. Single cortical cells and small accumulations of cells were spread throughout this region. At the ultrastructural level, the chromaffin cells located within the cortex in pig and rat adrenals formed close cellular contacts with cortical cells in all three zones. Our morphological data provide evidence for a possible paracrine role of chromaffin cells; this may be important for the neuroregulation of the adrenal cortex.

Effects of splanchnic nerve stimulation on the adrenal cortex may be mediated by chromaffin cells in a paracrine manner

The effects of nerve activation and of the catecholamines epinephrine and norepinephrine on adrenal corticosteroid release were investigated in intact isolated perfused pig adrenals with preserved nerve supply. To study the contact zones of medullary and cortical tissues, porcine adrenals were examined on the histological and ultrastructural levels. Splanchnic nerve activation stimulated in parallel the release of epinephrine (from a basal value of 0.31 +/- 0.11 to 8.13 +/- 0.60 microgram/min) and norepinephrine (from 0.76 +/- 0.68 to 12.94 +/- 3.58 micrograms/min) and the release of the corticosteroids cortisol (from 0.62 +/- 0.19 to 2.00 +/- 0.35 micrograms/min) and aldosterone (from 3.34 +/- 0.59 to 7.53 +/- 1.63 ng sigma in). Also, perfusion of the isolated adrenals with catecholamines provoked a significant release of the corticosteroids. Epinephrine (10(-6) M) stimulated the release of cortisol (from 0.59 +/- 0.31 to 2.66 +/- 0.34 micrograms/min) and aldosterone (from 2.12 +/- 0.42 to 4.68 +/- 0.92 ng/min). Norepinephrine (10(-6) M) stimulated the release of cortisol (from 0.26 +/- 0.07 to 1.28 +/- 0.10 micrograms/min) and aldosterone (from 1.28 +/- 0.37 to 3.57 +/- 0.80 ng/min). Using an immunostaining for synaptophysin, which is specific for neuroendocrine cells, chromaffin cells could be detected within all three zones of the adrenal cortex. The two endocrine tissues appear to be closely interwoven. On the ultrastructural level, medullary cells are in apposition to cortical cells, with close cellular contacts. These results show that the release of corticosteroids cortisol and aldosterone can be stimulated through the sympatho-adrenal system. Taking into consideration the close colocalization of cortical and medullary tissues, this stimulation may be mediated by chromaffin cells in a paracrine manner.

Adrenocortical atrophy of hypophysectomized rats can be reduced by corticotropin-releasing hormone (CRH)

The effects of high dose injections of corticotropin-releasing hormone (CRH) on the adrenal cortex of hypophysectomized rats were studied at the light- and electron-microscopical levels. Adrenocortical atrophy induced by hypophysectomy could be reduced by daily i.p. injection of 10 micrograms (3 nmol) CRH given for 3 days starting at day 5 after the operation. The cortex broadened, mostly because of hypertrophy of the zona fasciculata. Blood vessels were enlarged. Although the adrenocortical cells of hypophysectomized rats showed features of a functionally suppressed state, such as tubular mitochondria, the cells of CRH-treated animals showed characteristics of stimulated cells. The inner membrane of the mitochondria formed the typical densely packed vesicles of adrenocortical cells that are active in steroidogenesis. Lipid droplets were found to be reduced, and the cells developed filopodia at their surface. These morphological observations indicate that CRH influences the adrenal cortex via extrapituitary mechanisms.