Effect of Parenteral Antioxidants On Adrenal Pathobiology and Leukocytes in Hyperammonaemic Toxaemia

Infestation of sheep by L. cuprina larvae produces extensive skin wounds, severe dermatitis, hyperammonaemia and stress with adrenal necrosis and haemmorhage. In infested sheep, intramuscular (im) injections of Dl-Alpha tocopherol induced wool shedding and Desferrioxamine im prevented declines in white blood cells (WBC). In further trials, daily im injections of sodium ascorbate with Dl-alpha tocopherol, desferrioxamine and oral butylated-hydroxyanisole prevented adrenal damage and induced adrenocortical hypertrophy of the zona fasciculata. The treatment boosted the levels of mature and juvenile neutrophils, and blood glucose. Increases in toxic ammonia levels were correlated with increased toxic and band neutrophils, and globulin levels in treated sheep and toxic neutrophils in non-treated sheep. Decreases in serum zinc were correlated with declining lymphocytes and globulin levels. The results suggested that antioxidants protect and enhance adrenal activation in hyperammonaemic toxaemia. The changes in WBC, globulins and glucose were consistent with protected adrenocortical activation.     

Effect of Antioxidants on Ammonia Induced Cns-Renal Pathobiology in Sheep

The effect of antioxidants on ammonia induced CNS and renal pathobiology in 10 sheep infested by L. Cuprina larvae was investigated. The condition produces severe dermatitis, proliferation of macro-phages and hyperammonaemia, and free radicals may therefore be involved in the pathogenesis. Five of the sheep (treated group) were given daily intramuscular (im) injections of 2 g sodium ascorbate, 5.9 g dl-alpha tocopherol (11 days) and 3 g desferrioxamine mesylate (6 days) with 70 mg oral butylated-hydroxyanisole (11 days). The treatment prevented rises in jugular ammonia, creatinine, urea, sodium and pH, and decreases in water intake, urine output and glucose. The findings showed that antioxidants prevented ammonia induced CNS and renal pathobiology and suggest that free radicals contribute to the pathogenesis of the condition.     

Adrenocortical and renin-angiotensin systems in dynamics of experimental diabetes

Components of the adrenocortical system (adrenal and blood corticosteroid hormones and hepatic and renal 11β-hydroxysteroid dehydrogenase activity) and also activity of the most important enzyme of the renin-angiotensin system, tissue and blood angiotensin converting enzyme (ACE), have been investigated in dynamics of alloxan diabetes. The study has shown that the initial period of diabetes is characterized by activation of synthesis and secretion of adrenocortical hormones into blood. High blood glucose and glucocorticoid hormones increase activity of the renin-angiotensin system in lungs and decrease ACE secretion into blood. This is accompanied by a decrease of activity of the renin-angiotensin system in kidneys. Subsequent progression of diabetes resulted in impairments of physiologically determined correlations between the components of these systems. Development of experimental diabetes for 30 days was accompanied by sign of a decrease of the adrenal glucocorticoid function regardless of stable impairments of carbohydrate metabolism. Under these conditions increased adrenal and hepatic 11β-hydroxysteroid dehydrogenase activity may be responsible for maintenance of elevated levels of the main glucocorticoid in blood and tissues. Factor analysis revealed impairments in intersystem relationships between the adrenocortical and renin-angiotensin systems in experimental diabetes thus suggesting disintegration of regulatory systems.     

Glucose but not protein or fat load amplifies the cortisol response to psychosocial stress

We previously reported that glucose intake amplifies cortisol response to psychosocial stress and smoking in healthy young men, while low blood glucose levels prevented the stress-induced activation of the hypothalamus pituitary adrenal (HPA) axis. However, it remains unknown whether this modulation is specific for glucose load or a more common effect of energy availability. To elucidate this question, 37 healthy men, who fasted for at least 8 h before the experiment, were randomly assigned to four experimental groups, who received glucose (n = 8), protein (n = 10), fat (n = 10), and water (n = 9), one h before their exposure to the Trier Social Stress Test (TSST). Blood glucose levels were measured at baseline and following stress, while salivary cortisol was assessed repeatedly measured before after the TSST. The results show that both absolute cortisol levels and net cortisol increase were greater in the glucose group in comparison to the other groups (F(3,33) = 3.00, P < 0.05 and F(3,33) = 3.08, P < 0.05, respectively. No group differences were observed with respect to perceived stress and mood. Furthermore, the cortisol response was positively correlated with blood glucose changes (r = 0.49, P < 0.002). In conclusion, the results suggest a central mechanism responsible for regulation of energy balance and HPA axis activation, rather than peripheral mechanisms. We thus recommend controlling for blood glucose levels when studying HPA axis responsiveness.     

Effect of Family History of Type 2 Diabetes on White Blood Cell Count in Adult Women

Objective: To evaluate the effect of a first‐degree family history of type 2 diabetes on white blood cell (WBC) count, a risk factor for atherosclerotic vascular disease, in glucose‐tolerant adult women Research Methods and Procedures: WBC count was measured in 174 normal weight, overweight, and obese female offspring of type 2 diabetic patients (FH⁺) and 174 age‐ and BMI‐matched female controls with no family history of type 2 diabetes (FH^?). Other measurements included fat mass (FM), measured by body impedance analysis; central fat accumulation, evaluated by waist circumference; insulin resistance, estimated by homeostatic model assessment for insulin resistance (HOMA_IR); systolic and diastolic blood pressure; and fasting concentrations of glucose, insulin, and lipids. Results: WBC count, waist circumference, systolic blood pressure, and fasting levels of glucose, insulin, and triglycerides were significantly higher in FH⁺ than in FH^? subjects. In FH⁺ individuals, WBC count was positively associated with BMI, FM, waist circumference, HOMA_IR, and triglyceride and insulin concentrations, and negatively correlated with age and high‐density lipoprotein‐cholesterol. In FH^? subjects, WBC count was directly associated with BMI, FM, waist circumference, and triglyceride and insulin concentrations, and inversely correlated with age and high‐density lipoprotein‐cholesterol. After multivariate analyses, WBC count maintained a significant association with age, systolic blood pressure, and HOMA_IR in FH⁺ subjects and with age, BMI, FM, and triglycerides in FH^? individuals. Discussion: This study indicates that WBC count is increased in adult women with genetic predisposition to type 2 diabetes, and its main correlates are insulin resistance in FH⁺ and adiposity in FH^? individuals.     

Novel zebrafish behavioral assay to identify modifiers of the rapid,nongenomic stress response

When vertebrates face acute stressors, their bodies rapidly undergo a repertoire of physiological and behavioral adaptations, which is termed the stress response. Rapid changes in heart rate and blood glucose levels occur via the interaction of glucocorticoids and their cognate receptors following hypothalamic‐pituitary‐adrenal axis activation. These physiological changes are observed within minutes of encountering a stressor and the rapid time domain rules out genomic responses that require gene expression changes. Although behavioral changes corresponding to physiological changes are commonly observed, it is not clearly understood to what extent hypothalamic‐pituitary‐adrenal axis activation dictates adaptive behavior. We hypothesized that rapid locomotor response to acute stressors in zebrafish requires hypothalamic‐pituitary‐interrenal (HPI) axis activation. In teleost fish, interrenal cells are functionally homologous to the adrenocortical layer. We derived eight frameshift mutants in genes involved in HPI axis function: two mutants in exon 2 of mc2r (adrenocorticotropic hormone receptor), five in exon 2 or 5 of nr3c1 (glucocorticoid receptor [GR]) and two in exon 2 of nr3c2 (mineralocorticoid receptor [MR]). Exposing larval zebrafish to mild environmental stressors, acute changes in salinity or light illumination, results in a rapid locomotor response. We show that this locomotor response requires a functioning HPI axis via the action of mc2r and the canonical GR encoded by nr3c1 gene, but not MR (nr3c2). Our rapid behavioral assay paradigm based on HPI axis biology can be used to screen for genetic and environmental modifiers of the hypothalamic‐pituitary‐adrenal axis and to investigate the effects of corticosteroids and their cognate receptor interactions on behavior.     

Positive reinforcement training affects hematologic and serum chemistry values in captive chimpanzees (Pan troglodytes)

Positive reinforcement training (PRT) techniques have received considerable attention for their stress reduction potential in the behavioral management of captive nonhuman primates. However, few published empirical studies have provided physiological data to support this position. To address this issue, PRT techniques were used to train chimpanzees (Pan troglodytes) to voluntarily present a leg for an intramuscular (IM) injection of anesthetic. Hematology and serum chemistry profiles were collected from healthy chimpanzees (n=128) of both sexes and various ages during their routine annual physical examinations over a 7-year period. Specific variables potentially indicative of acute stress (i.e., total white blood cell (WBC) counts, absolute segmented neutrophils (SEG), glucose (GLU) levels, and hematocrit (HCT) levels) were analyzed to determine whether the method used to administer the anesthetic (voluntary present for injection vs. involuntary injection) affected the physiological parameters. Subjects that voluntarily presented for an anesthetic injection had significantly lower mean total WBC counts, SEG, and GLU levels than subjects that were involuntarily anesthetized by more traditional means. Within-subjects analyses revealed the same pattern of results. This is one of the first data sets to objectively demonstrate that PRT for voluntary presentation of IM injections of anesthetic can significantly affect some of the physiological measures correlated with stress responses to chemical restraint in captive chimpanzees.     

HMGB1 contributes to glomerular endothelial cell injury in ANCA‐associated vasculitis through enhancing endothelium–neutrophil interactions

Our previous studies demonstrated that high mobility group box‐1 (HMGB1), a typical damage‐associated molecular pattern (DAMP) protein, is associated with the disease activity of antineutrophil cytoplasmic antibody (ANCA)‐associated vasculitis (AAV). Moreover, HMGB1 participates in ANCA‐induced neutrophil activation. The current study aimed to investigate whether HMGB1 regulated the interaction between neutrophils and glomerular endothelial cells (GEnC) in the presence of ANCA. Correlation analysis on HMGB1 levels in AAV patients and soluble intercellular cell adhesion molecule‐1 (sICAM‐1) levels or vascular endothelial growth factor (VEGF) levels, which are markers of endothelial cell activation, was performed. The effect of HMGB1 on neutrophil migration towards GEnC, respiratory burst and degranulation of neutrophils in coculture conditions with GEnC was measured. The activation of neutrophils, the activation and injury of GEnC, and the consequent pathogenic role of injured GEnC were evaluated. Plasma levels of HMGB1 correlated with sICAM‐1 and VEGF (r = 0.73, P < 0.01; r = 0.41, P = 0.04) in AAV patients. HMGB1 increased neutrophil migration towards GEnC, as well as respiratory burst and degranulation of neutrophils in the presence of ANCA in the coculture system. In the presence of robust neutrophil activation, GEnC were further activated and injured in the coculture system of GEnC and neutrophils. In addition, injured GEnC could produce TF‐positive leuco‐endothelial microparticles and endothelin‐1 (ET‐1), while NF‐κB was phosphorylated (S529) in the injured GEnC. Plasma levels of HMGB1 correlated with endothelial cell activation in AAV patients. HMGB1 amplified neutrophil activation and the activation and injury of GEnC in the presence of ANCA.     

Modulation of the effects of ascorbic acid on lipid peroxidation by tocopherol in adrenocortical mitochondria

Studies were done to evaluate the role of alpha-tocopherol in modulating the effects of ascorbic acid (AA) on lipid peroxidation (LP) by adrenocortical mitochondria. In control mitochondria from the inner (zona reticularis) or outer (zona fasciculata plus zona glomerulosa) zones of the guinea pig adrenal cortex, subphysiological concentrations of AA stimulated LP but higher levels had little or no effect. However, after depletion of adrenal tocopherol, even physiological concentrations of AA exerted prooxidant effects, stimulating LP. To assess the antioxidant potency of AA, its effects to inhibit ferrous ion (Fe2+)-induced LP were determined. Mitochondria from the outer zone contained far more alpha-tocopherol than those from the inner zone and were more sensitive to the antioxidant effects of AA. After tocopherol depletion, the antioxidant potency of AA in outer zone mitochondria decreased, but there was little change in the inner zone. The results indicate that the actions of AA are determined in part by mitochondrial tocopherol content, and, as a result, vary in the different zones of the adrenal cortex.     

The effect of modulators of free-radical oxidation on the functional activity of phagocytes

The influence of free-radical oxidation inhibitors (alpha tocopherol) and stimulators (levamisole and alriblastin) on the processes of the peroxide oxidation of lipids in blood serum and the phagocytic activity of peripheral blood neutrophils in Salmonella infection in rabbits at an early age is accompanied by phasic changes in the peroxide oxidation of lipids with activation at the early period of the development of the infection. The synchronism of changes in the peroxide oxidation of lipids and in the phagocytic activity of neutrophils is observed. Alpha tocopherol inhibits the peroxide oxidation of lipids and decreases the degree of the completeness of phagocytosis. Alriblastin stimulates the peroxide oxidation of lipids and increases the phagocytic activity of neutrophils.     

Peripheral blood neutrophil activation patterns are associated with pulmonary inflammatory responses to lipopolysaccharide in humans

Increased nuclear accumulation of NF-kappaB in LPS-stimulated peripheral blood neutrophils has been shown to be associated with more severe clinical course in patients with infection associated acute lung injury. Such observations suggest that differences in neutrophil response may contribute to the pulmonary inflammation induced by bacterial infection. To examine this question, we sequentially measured LPS-induced DNA binding of NF-kappaB in neutrophils collected from healthy humans on at least three occasions, each separated by at least 2 wk, and then determined pulmonary inflammatory responses after instillation of LPS into the lungs. Consistent patterns of peripheral blood neutrophil responses, as determined by LPS-induced NF-kappaB DNA binding, were present in volunteers, with a >80-fold difference between individuals in the mean area under the curve for NF-kappaB activation. The number of neutrophils recovered from bronchoalveolar lavage after exposure to pulmonary LPS was significantly correlated with NF-kappaB activation in peripheral blood neutrophils obtained over the pre-LPS exposure period (r = 0.65, p = 0.009). DNA binding of NF-kappaB in pulmonary neutrophils also was associated with the mean NF-kappaB area under the curve for LPS-stimulated peripheral blood neutrophils (r = 0.63, p = 0.01). Bronchoalveolar lavage levels of IL-6 and TNFRII were significantly correlated with peripheral blood neutrophil activation patterns (r = 0.75, p = 0.001 for IL-6; and r = 0.48, p = 0.049 for TNFRII. These results demonstrate that stable patterns in the response of peripheral blood neutrophils to LPS exist in the human population and correlate with inflammatory response following direct exposure to LPS in the lung.     

Influence of hot environments on some blood variables of sheep

Thirty-two Polwarth sheep of ages up to 1 year were observed under temperatures varying from 10.5 to 46.5°C. The following blood cell counts were made: erythrocyte (RBC), leucocyte (WBC), eosinophil (EOS), neutrophil (NEU), lymphocyte (LYM) and monocyte (MON). Other traits measured were: haemoglobin (HB), haematocrit (HT), blood glucose (GLU) and serum protein (PROT). Multivariate analysis of variance was used and the results showed a significant (P<0.001) effect for the interaction of shearing and temperature treatment. Under temperatures >25°C, sheep presented a decrease of RBC, WBC, HB and HT, these differences being greater in the shorn than in the unshorn animals. Unshorn animals presented higher variations in EOS, NEU, LYM, MON and GLU. Blood glucose increased under high temperatures in the shorn animals (from 56.36±0.65 mg/100 ml to 60.52±0.69 mg/100 ml) as in the unshorn animals (from 54.72±0.74 mg/100 ml to 57.56±0.77 mg/100 ml).     

Cardiovascular effects produced by injections of thyrotropin-releasing hormone in specific preoptic and hypothalamic nuclei in the rat

Microinjection of 1.4 pmol TRH (0.5 ng; 50–150 nl) into both the preoptic suprachiasmatic nucleus (pos) and the A6800–7000 region of the medial preoptic nucleus (pom) produced increases in blood pressure and heart rate of 7% and 19%, respectively; heart rate responses in these two areas were higher than those occurring in other areas tested. TRH induced a significant increase in blood pressure and heart rate in the posterior hypothalamic nucleus (nhp) and increased heart rate only in the anterior (nha) and dorsomedial (ndm) hypothalamic nuclei. A small decrease in both blood pressure and heart rate resulted with TRH injections in the A7050–7400 region of the pom. No changes in respiratory rate or rectal temperature were observed at any site with this dose of TRH. Preliminary studies into the mechanism of the cardiovascular actions of TRH suggested that inhibition of the parasympathetic nerves to the heart make a partial contribution to the TRH-induced heart rate increase in the pos and that adrenal catecholamine release mediates the TRH response in the nhp. Neither methylatropine pretreatment nor adrenalectomy prevented the response to TRH injected into the nha, suggesting that activation of the cardiac sympathetic nerves may mediate TRH actions in this region. In the ndm, neither methylatropine nor adrenalectomy prevented the response to TRH; however, there was a tendency for the response to be less after methylatropine. Therefore, both inhibition of the parasympathetic and activation of the sympathetic nervous systems may contribute to the response observed, but no adrenal involvement could be demonstrated. Discrete injections of 0.8 nmol TRH produced increases in heart rate and blood pressure in all preoptic and hypothalamic nuclei tested with accompanying changes in respiratory rate and rectal temperature in some areas. Lateral cerebral ventricle injections of as little as 2.8 pmol TRH produced increases in blood pressure and heart rate; cardiovascular responses to higher doses (0.8–22 nmol) in the ventricle were often accompanied by arousal, piloerection, “wet dog” shakes and changes in respiratory rate and rectal temperature. Previous immunohistochemical demonstration of nerve cells and fibers in the preoptic-hypothalamic area and the present finding of specific sites responsive to low dose TRH injections (1.4 pmol) both support a physiological role for this peptide in central control of the cardiovascular system.     

Inhibition of glucose metabolism sensitizes tumor cells to death receptor-triggered apoptosis through enhancement of death-inducing signaling complex formation and apical procaspase-8 processing

Tumors display a high rate of glucose uptake and glycolysis. We investigated how inhibition of glucose metabolism could affect death receptor-mediated apoptosis in human tumor cells of diverse origin. We show that both substitution of glucose for pyruvate and treatment with 2-deoxyglucose enhanced apoptosis induced by tumor necrosis factor (TNF)-alpha, CD95 agonistic antibody, and TNF-related apoptosis-inducing ligand (TRAIL). Inhibition of glucose metabolism enhanced killing of myeloid leukemia U937, cervical carcinoma HeLa, and breast carcinoma MCF-7 cells upon death receptor ligation. Caspase activation, mitochondrial depolarization, and cytochrome c release were increased under these conditions. Glucose deprivation-mediated sensitization to apoptosis was prevented in MCF-7 cells overexpressing BCL-2. Interestingly, the human B-lymphoblastoid cell line SKW6.4, a prototype for mitochondria-independent death receptor-induced apoptosis, was also sensitized to anti-CD95 and TRAIL-induced apoptosis under glucose-free conditions. Changes in c-FLIP(L) and cFLIPs levels were observed in some but not all the cell lines studied following glucose deprivation. Glucose deprivation enhanced death receptor-triggered formation of death-inducing signaling complex and early processing of procaspase-8. Altogether, these results suggest that the glycolytic pathway may be an important target for therapeutic intervention to sensitize tumor cells to selectively toxic soluble death ligands or death ligand-expressing cells of the immune system by facilitating the activation of initiator caspase-8.     

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

Summary 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 g (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.     

Suppression of GLUT1; A new strategy to prevent diabetic complications

High blood glucose results in high glucose levels in retina, because GLUT1, the sole glucose transporter between blood and retina, transports more glucose when blood glucose is high. This is the ultimate cause of diabetic retinopathy. Knockdown of GLUT1 by intraocular injections of a pool of siRNAs directed against SLC2A1 mRNA which codes for GLUT1 significantly reduced mean retinal glucose levels in diabetic mice. Systemic treatment of diabetic mice with forskolin or genistein, which bind GLUT1 and inhibit glucose transport, significantly reduced retinal glucose to the same levels seen in non‐diabetics. 1,9‐Dideoxyforskolin, which binds GLUT1 but does not stimulate adenylate cyclase had an equivalent effect to that of forskolin regarding lowering retinal glucose in diabetics indicating that cyclic AMP is noncontributory. GLUT1 inhibitors also reduced glucose and glycohemoglobin levels in red blood cells providing a peripheral biomarker for the effect. In contrast, brain glucose levels were not increased in diabetics and not reduced by forskolin. Treatment of diabetics with forskolin prevented early biomarkers of diabetic retinopathy, including elevation of superoxide radicals, increased expression of the chaperone protein β2 crystallin, and increased expression of vascular endothelial growth factor (VEGF). These data identify GLUT1 as a promising therapeutic target for prevention of diabetic retinopathy. J. Cell. Physiol. 228: 251–257, 2013. © 2012 Wiley Periodicals, Inc.     

Hypothalamic-pituitary disconnection in fetal sheep blocks the peripartum increases in adrenal responsiveness and adrenal ACTH receptor expression

Although it has been recognized for over a decade that hypothalamic-pituitary disconnection (HPD) in fetal sheep prevents the late gestation rise in plasma cortisol concentrations, the underlying mechanisms remain unclear. We hypothesized that reductions in adrenal responsiveness and ACTH receptor (ACTH-R) expression may be mediating factors. HPD or sham surgery was performed at 120 days of gestation, and catheters were placed for blood sampling. At approximately 138 days of gestation, fetuses were killed, and adrenals were removed for cell culture and analyses of ACTH-R mRNA and protein. After 48 h, adrenocortical cells were stimulated with ACTH for 2 h, and the medium was collected for cortisol measurement. The same cells were incubated overnight with medium or medium containing ACTH or forskolin (FSK), followed by ACTH stimulation (as above) and cortisol and cellular ACTH-R mRNA analyses. HPD prevented the late gestation increase in plasma cortisol and bioactive ACTH and reduced adrenal ACTH-R mRNA and protein levels by over 35%. HPD cells secreted significantly less cortisol than sham cells (3.2 +/- 1.2 vs. 47.3 +/- 11.1 ng.ml(-1).2 h(-1)) after the initial ACTH stimulation. Overnight incubation of HPD cells with ACTH or FSK restored cortisol responses to acute stimulation to levels seen in sham cells initially. ACTH-R mRNA levels in cells isolated from HPD fetuses were decreased by over 60%, whereas overnight incubation with ACTH or FSK increased levels by approximately twofold. Our findings indicate that the absence of the cortisol surge in HPD fetuses is a consequence, at least in part, of decreased ACTH-R expression and adrenal responsiveness.     

Species differences in adrenal lipid peroxidation: role of alpha-tocopherol

Previous reports have noted high levels of lipid peroxidation (LP) in vitro in a variety of adrenocortical preparations. However, we have observed that susceptibility to adrenal LP seems to vary considerably from species to species. The current study was done to confirm these apparent species differences in adrenal LP in vitro and to determine if they were attributable to differences in alpha-tocopherol content. Incubation of mitochondrial or microsomal preparations from guinea pig or rabbit adrenal glands with ferrous ion (Fe2+) caused a time-dependent increase in the formation of thiobarbituric acid reactive substances (TBARS) accompanied by depletion of alpha-tocopherol. By contrast, incubation of adrenal mitochondria or microsomes from rats or monkeys with Fe2+ had little or no detectable effect on TBARS and basal adrenal alpha-tocopherol levels were five to ten-fold greater than those in guinea pigs or rabbits. In addition, there was little change in alpha-tocopherol concentrations during incubation of rat or monkey adrenal tissue. Dietary alpha-tocopherol deficiency in rats reduced adrenal alpha-tocopherol to concentrations approximating those in guinea pigs. Incubation with Fe2+ induced high levels of TBARS in adrenal mitochondria and microsomes from the alpha-tocopherol deficient rats. Conversely, dietary alpha-tocopherol supplementation in rabbits increased adrenal alpha-tocopherol levels and prevented Fe2+ induced TBARS formation in mitochondria and microsomes. The results indicate that there are large species differences in adrenal susceptibility to LP in vitro and that these differences are at least partly attributable to species differences in adrenal alpha-tocopherol concentrations.     

Prolactin and the expression of suppressor of cytokine signaling-3 in the sheep adrenal gland before birth

The fetal pituitary-adrenal axis plays a key role in the fetal response to intrauterine stress and in the timing of parturition. The fetal sheep adrenal gland is relatively refractory to stimulation in midgestation (90-120 days) before the prepartum activation, which occurs around 135 days gestation (term=147+/-3 days). The mechanisms underlying the switch from adrenal quiescence to activation are unclear. Therefore, we have investigated the expression of suppressor of cytokine signaling-3 (SOCS-3), a putative inhibitor of tissue growth in the fetal sheep adrenal between 50 and 145 days gestation and in the adrenal of the growth-restricted fetal sheep in late gestation. SOCS-3 is activated by a range of cytokines, including prolactin (PRL), and we have, therefore, determined whether PRL administered in vivo or in vitro stimulates SOCS-3 mRNA expression in the fetal adrenal in late gestation. There was a decrease (P<0.005) in SOCS-3 expression in the fetal adrenal between 54 and 133 days and between 141 and 144 days gestation. Infusion of the dopaminergic agonist, bromocriptine, which suppressed fetal PRL concentrations but did not decrease adrenal SOCS-3 mRNA expression. PRL administration, however, significantly increased adrenal SOCS-3 mRNA expression (P<0.05). Similarly, there was an increase (P<0.05) in SOCS-3 mRNA expression in adrenocortical cells in vitro after exposure to PRL (50 ng/ml). Placental and fetal growth restriction had no effect on SOCS-3 expression in the adrenal during late gestation. In summary, the decrease in the expression of the inhibitor SOCS-3 after 133 days gestation may be permissive for a subsequent increase in fetal adrenal growth before birth. We conclude that factors other than PRL act to maintain adrenal SOCS-3 mRNA expression before 133 days gestation but that acute elevations of PRL can act to upregulate adrenal SOCS-3 expression in the sheep fetus during late gestation.     

Influence of dystocia on white blood cell and blood neutrophil counts in mares

A retrospective study was done on total white blood cell (WBC) and blood neutrophil counts of 41 mares referred to one of two veterinary hospitals for correction of dystocia. The mares were 2 to 19 years of age and included draft, light, and pony breeds. The WBC and neutrophil counts were performed at varying intervals from time of admission to 10 d after delivery of the feti. Retrospective analyses of WBC and neutrophil counts from 10 normal foaling mares from two Pennsylvania breeding farms (Thoroughbred and Trakehner) and from 14 normal foaling pony mares were done as controls. Mean WBC (10446 +/- 2296 cells/mul) and neutrophil (6850 +/- 2136 cells/mul) counts on the day of delivery in mares with normal parturition were slightly elevated over values reported as normal in the literature. The mean blood cell counts gradually declined to 6124 +/- 1255 WBC/mul and 3692 +/- 409 neutrophils/mul on Day 2 postpartum and returned to normal baseline values by Day 3 postpartum (8868 +/- 2693 WBC/mul, 4298 +/- 1966 neutrophils/mul). No toxic neutrophils were present in mares with normal delivery. Mean WBC (11346 +/- 3298 cells/mul) was elevated on the day of delivery in mares with dystocia as a result of neutrophilia with a left shift (9297 +/- 3298 neutrophils/mul). An apparently faster decline occurred in WBC and neutrophil counts of mares with dystocia than in mares with normal delivery, until a marked leukopenia (3905 +/- 1292 WBC/mul) and neutropenia (1570 +/- 1340 neutrophils/mul) occurred on Day 3 postpartum. The leukopenia and neutropenia persisted until Day 5 postpartum. Toxic neutrophils were present in several mares with dystocia.