Transrectal ultrasonography of the adrenal glands in donkeys (Equus asinus)

Little information is available for medical imaging in donkeys and no report about adrenal glands ultrasonography can be found in scientific literature. The feasibility of transrectal ultrasonography of the adrenal glands was tested on 30 healthy donkeys using a 10 MHz linear transducer. Mean age of animals was 10.7 ±4.8 years, mean weight 275.0 ±62.9 Kg and mean height 126.7 ±7.1 cm. The left adrenal gland was visualized in all donkeys. The right gland ultrasonography was not feasible in seven animals with a height less than 116 cm. The left gland was visualized as a linear or slightly curved structure, the right gland was most often S-shaped. In both glands, an hypechoic peripheral zone was identified as the cortex with an inner, hyperechoic medulla. The length was 5.49 ±1.90 cm and 5.15 ±1.10 cm for right and left gland, respectively. Right gland whole and medullary thickness were 0.71 ±0.11 cm and 0.24 ±0.09 cm, 0.65 ±0.13 cm and 0.21 ±0.07 cm, 0.56 ±0.17 cm and 0.25 ±0.07 cm for cranial pole, middle point and caudal pole respectively. Left gland whole and medullary thickness were 0.69 ±0.13 cm and 0.25 ±0.09 cm, 0.66 ±0.13 cm and 0.23 ±0.09 cm, 0.57 ±0.15 cm and 0.26 ±0.09 cm for cranial pole, middle point and caudal pole respectively. There was a significant correlation between height and the entire length of the left gland. Ultrasonography of the adrenal glands is a suitable tool for evaluation of both adrenal glands in most of the donkey. The size is a limiting factor for proper visualization of the right gland

Sexual Differentiation of Circadian Clock Function in the Adrenal Gland

Sex differences in glucocorticoid production are associated with increased responsiveness of the adrenal gland in females. However, the adrenal-intrinsic mechanisms that establish sexual dimorphic function remain ill defined. Glucocorticoid production is gated at the molecular level by the circadian clock, which may contribute to sexual dimorphic adrenal function. Here we examine sex differences in the adrenal gland using an optical reporter of circadian clock function. Adrenal glands were cultured from male and female Period2::Luciferase (PER2::LUC) mice to assess clock function in vitro in real time. We confirm that there is a pronounced sex difference in the intrinsic capacity to sustain PER2::LUC rhythms in vitro, with higher amplitude rhythms in adrenal glands collected from males than from females. Changes in adrenal PER2::LUC rhythms over the reproductive life span implicate T as an important factor in driving sex differences in adrenal clock function. By directly manipulating hormone levels in adult mice in vivo, we demonstrate that T increases the amplitude of PER2::LUC rhythms in adrenal glands of both male and female mice. In contrast, we find little evidence that ovarian hormones modify adrenal clock function. Lastly, we find that T in vitro can increase the amplitude of PER2::LUC rhythms in male adrenals but not female adrenals, which suggests the existence of sex differences in the mechanisms of T action in vivo. Collectively these results reveal that activational effects of T alter circadian timekeeping in the adrenal gland, which may have implications for sex differences in stress reactivity and stress-related disorders

Localisation of the melanocortin-2-receptor and its accessory proteins in the developing and adult adrenal gland

The melanocortin-2-receptor (MC2R)/MC2R accessory protein (MRAP) complex is critical to the production of glucocorticoids from the adrenal cortex. Inactivating mutations in either MC2R or MRAP result in the clinical condition familial glucocorticoid deficiency. The localisation of MC2R together with MRAP within the adrenal gland has not previously been reported. Furthermore, MRAP2, a paralogue of MRAP, has been shown in vitro to have a similar function to MRAP, facilitating MC2R trafficking and responsiveness to ACTH. Despite similar MC2R accessory functions, in vivo, patients with inactivating mutations of MRAP fail to be rescued by a functioning MRAP2 gene, suggesting differences in adrenal expression, localisation and/or function between the two MRAPs. In this study on the rat adrenal gland, we demonstrate that while MRAP and MC2R are highly expressed in the zona fasciculata, MRAP2 is expressed throughout the adrenal cortex in low quantities. In the developing adrenal gland, both MRAP and MRAP2 are equally well expressed. The MC2R/MRAP2 complex requires much higher concentrations of ACTH to activate compared with the MC2R/MRAP complex. Interestingly, expression of MC2R and MRAP in the undifferentiated zone would support the notion that ACTH may play an important role in adrenal cell differentiation and maintenance

Contribution of the adrenal gland to the production of androstenedione and testosterone during the first two years of life

Androstenedione and testosterone were measured in whole adrenal glands of 56 previously healthy boys who died suddenly between birth and 2 yr of age. In each adrenal gland, the concentration of androstenedione considerably exceeded that of testosterone. The highest concentrations were found during the first week of life (median, 295 ng/g; range, 98- 320 ng/g). Thereafter, values decreased rapidly until the end of the first year of life (median, 10 ng/g; range, 4.4-22.7 ng/g). Adrenal testosterone concentrations averaged 15% of those of androstenedione in the same gland and similarly decreased until the end of the first year. The decrease of adrenal androgen concentrations paralleled the involution of the fetal adrenal zone. A close correlation existed between the concentration of androstenedione in adrenal tissue and plasma. However, no correlation existed between adrenal and plasma testosterone. When the adrenals and testes of the same infant were compared, there was 10 times more androstenedione in the adrenals than in the testes during the first 2 yr of life. The testes contained more testosterone than the adrenals only during the first 4 months. Thus, in infant boys the adrenals are the main source of androstenedione during the first 2 yr. After the sixth month of life, they also are the main source of testosterone

Corticosteroid-Binding Globulin is expressed in the adrenal gland and its absence impairs corticosterone synthesis and secretion in a sex-dependent manner

Corticosteroid-binding globulin (CBG) is synthesized by the liver and secreted into the bloodstream where binds to glucocorticoids. Thus CBG has the role of glucocorticoid transport and free hormone control. In addition, CBG has been detected in some extrahepatic tissues without a known role. CBG-deficient mice show decreased total corticosterone levels with missing of classical sexual dimorphism, increased free corticosterone, higher adrenal gland size and altered HPA axis response to stress. Our aim was to ascertain whether CBG deficiency could affect the endocrine synthetic activity of adrenal gland and if the adrenal gland produces CBG. We determined the expression in adrenal gland of proteins involved in the cholesterol uptake and its transport to mitochondria and the main enzymes involved in the corticosterone, aldosterone and catecholamine synthesis. The results showed that CBG is synthesized in the adrenal gland. CBG-deficiency reduced the expression of ACTH receptor, SRB1 and the main genes involved in the adrenal hormones synthesis, stronger in females resulting in the loss of sexual dimorphism in corticosteroid adrenal synthesis, despite corticosterone content in adrenal glands from CBG-deficient females was similar to wildtype ones. In conclusion, these results point to an unexplored and relevant role of CBG in the adrenal gland functionality related to corticosterone production and release

Reaction of chickens to graduated length of exposure to stress

The reactions of 60 day old chickens Arbor Acres 60 X Vantress to immobilization stress lasting 1/2, 1, 2, 4 hours and to application of ACTH, manifested by activity changes in the systems hypophysis-adrenal gland and hypophysis-thyroid gland were studied. The highest activity increase in the two neuro-endocrine systems of the chickens was found to occur after 1/2 hour exposure to stress. With prolonged stress the responses weakened and after 4 hours most of the values gradually regressed to their initial level. The responses of both systems were synchronized. Reactions of the chickens differed from those of laboratory rats in which an increased activity of the hypophysis-adrenal gland system coincided with attenuation of the hypophysis-thyroid gland system

Numerical Evaluation of Microwave Thermal Ablation to Treat Small Adrenocortical Masses

In this paper microwave thermal ablation is numerically evaluated in the context of a treatment for Conn’s Syndrome. This condition is caused by a benign shallow tumour in the cortex of adrenal gland. The modelling and design of microwave applicator to deliver thermal ablation to the adrenal gland requires accurate tissue characterisation. Measuring the dielectric properties of the constituent tissues in the adrenal gland, i.e. cortex and medulla, enables more accurate numerical modelling for electromagnetic and thermal simulations. This study presents an anatomically and dielectrically realistic numerical model of the adrenal gland, and investigates the feasibility of applying controlled heating to small targets in the adrenal cortex. In addition, the use of dielectric contrast between the fat and the cortex of the adrenal gland to focus the thermal energy in the gland has also been studied. Being conscious of limitations of numerical simulation of complex multiphysics problems like the microwave ablative treatment, calculated results provide a preliminary description of the electromagnetic and thermal phenomena involved

Ex vivo MRI and histological comparison of the canine adrenal glands.

Cross-sectional imaging is widely used to characterize adrenal gland tumors in humans. In small animal veterinary medicine, while some studies have attempted to distinguish between types of adrenal gland neoplasia using CT, peer-reviewed studies investigating canine adrenal glands on MRI are scant. This prospective, pilot, single-center, method comparison, cadaveric study aimed to assess the agreement between ex vivo MRI findings and analogous histopathological findings of the adrenal glands in dogs. The adrenal glands of randomly selected dogs presented for necropsy were examined by MRI (n = 31). Additionally, five adrenal masses in dogs who underwent invasive adrenalectomy (including three adrenocortical carcinomas, one pheochromocytoma, and one adenoma) were imaged. Subsequently, gross pathology and histopathology of all the specimens were performed and correlated with the imaging findings. Adrenal gland lesions were identified on MRI with a sensitivity of 24%, a specificity of 100%, a positive predictive value of 100%, a negative predictive value of 31%, and an accuracy of 45%. The present study provides MRI features of multiple adrenal gland lesions that had never been described in dogs, including cortical hyperplasia, nodular fibrosis, hemorrhage, or multiple tumors, such as adenoma, carcinoma, and hemangiosarcoma. While MRI identified numerous adrenal gland lesions, a significant portion of those went undetected. Therefore, the absence of adrenal gland lesions on MRI does not exclude the possibility of histological lesions being present

Preservation of the retrohepatic vena cava during recipient hepatectomy for orthotopic transplantation of the liver.

A modified final phase of recipient hepatectomy in orthotopic hepatic transplantation is presented. It involves preservation of the retrohepatic vena cava "in toto" to decrease the risk of injury to the adrenal gland and assure better control of the adrenal vein, as well as the forming of the caval cuffs, for the subsequent implantation of the donor liver

Naloxone inhibits and morphine potentiates. The adrenal steroidogenic response to ACTH

The adrenal actions were stereospecific since neither the positve stereoisomer of morphine, nor that of naloxone, had any effect on the adrenal response to exogenous adrenocorticotrophic hormone (ACTH). The administration of human beta endorphin to phyophysectomized rats had no effect on the adrenal corticosterone concentration nor did it alter the response of the adrenal gland to ACTH. These results indicate that morphine can potentiate the action of ACTH on the adrenal by a direct, stereospecific, dose dependent mechanism that is prevented by naloxone pretreatment and which may involve competition for ACTH receptors on the corticosterone secreting cells of the adrenal cortex