Alfaxalone increases measured progesterone concentration in neutered male cats when determined by immunoreactivity.

Objective: Alfaxalone is a commonly used anesthetic agent in small animals. In cats, alfaxalone can be administered as an IM agent to achieve clinically useful sedation or anesthesia, negating the need for IV injection in difficult patients. The molecular structure of alfaxalone is similar to the hormone progesterone (P4).

Early transcriptomic response of mouse adrenal gland and Y-1 cells to dexamethasone.

Glucocorticoids have short- and long-term effects on adrenal gland function and development. RNA sequencing (RNA-seq) was performed to identify early transcriptomic responses to the synthetic glucocorticoid, dexamethasone (Dex), in vitro and in vivo. In total, 1711 genes were differentially expressed in the adrenal glands of the 1-h Dex-treated mice.

The Herbicide Atrazine Potentiates Angiotensin II-Induced Aldosterone Synthesis and Release From Adrenal Cells.

Atrazine is one of the most commonly used pre-emergence and early post-emergence herbicides in the world. We have shown previously that atrazine does not directly stimulate the pituitary or adrenal to trigger hormone release but acts centrally to activate a stress-like activation of the hypothalamic-pituitary-adrenal axis. In doing so, atrazine treatment has been shown to cause adrenal morphology changes characteristic of repeated stress.

Expression of Rasd1 in mouse endocrine pituitary cells and its response to dexamethasone.

Dexamethasone-induced Ras-related protein 1 (Rasd1) is a member of the Ras superfamily of monomeric G proteins that have a regulatory function in signal transduction. Rasd1, also known as Dexras1 or AGS1, is rapidly induced by dexamethasone (Dex). While prior data indicates that Rasd1 is highly expressed in the pituitary and that the gene may function in regulation of corticotroph activity, its exact cellular localization in this tissue has not been delineated.

Pet Food-Associated Dietary Exogenous Thyrotoxicosis: Retrospective Study (2016-2018) and Clinical Considerations.

Dietary exogenous thyrotoxicosis is infrequently observed in pet food. A retrospective evaluation of pet food investigations (PFI) was conducted for 17 dogs, including review of medical records, dietary and environmental exposure interviews, food testing, and regulatory action. Five PFIs occurring between 2016 and 2018 involved 7 food products including 2 food types, jerky treats or canned food, made from beef or bison.

Effect of EDTA on measurement of cortisol and thyroxine by chemiluminescent enzyme immunoassay in dogs.

The addition of ethylenediamine tetra-acetic acid (EDTA) to serum can affect the measurement of cortisol by chemiluminescent enzyme immunoassay (CEIA); addition of magnesium chloride (MgCl) may reverse the effects. However, similar characteristics for thyroxine (T4) measurement are unknown. We measured cortisol and T4 in paired EDTA-anticoagulated plasma and serum samples from 50 dogs.

Low-dose ACTH stimulation testing in dogs suspected of hypoadrenocorticism.

Background: Low-dose ACTH stimulation testing would lower cost and may increase sensitivity for identification of partial ACTH deficiency.

Hypothesis: (1) The low-dose ACTH stimulation test will provide comparable results to the standard-dose ACTH stimulation test in dogs suspected of hypoadrenocorticism and (2) partial ACTH deficiency exists in dogs and can result in chronic, intermittent gastrointestinal signs.

Animals: Thirty-one client-owned dogs suspected of having hypoadrenocorticism.

Characterization of Activation of the Hypothalamic-Pituitary-Adrenal Axis by the Herbicide Atrazine in the Female Rat.

Atrazine (ATR) is a commonly used pre-emergence and early postemergence herbicide. Rats gavaged with ATR and its chlorometabolites desethylatrazine (DEA) and deisopropylatrazine (DIA) respond with a rapid and dose-dependent rise in plasma corticosterone, whereas the major chlorometabolite, diaminochlorotriazine (DACT), has little or no effect on corticosterone levels. In this study, we investigated the possible sites of ATR activation of the hypothalamic-pituitary-adrenal (HPA) axis.

Excess EDTA interferes with cortisol measurement using a solid-phase, chemiluminescent enzyme immunoassay.

Hormone assays that use a solid-phase, automated, chemiluminescent enzyme immunoassay (CEIA) with an alkaline phosphatase-tagged hormone or antibody as a reporter are performed on serum or EDTA plasma in our laboratory. CEIA cortisol results appeared to increase in the presence of excess EDTA. We investigated the effect of the addition of different amounts of EDTA on cortisol concentrations in pooled canine serum samples.

Effect of laparotomy on the pituitary-adrenal axis in dogs.

OBJECTIVE To assess effects of major abdominal surgery on serum cortisol and aldosterone and plasma canine ACTH (cACTH) concentrations. ANIMALS 39 healthy dogs undergoing laparotomy during veterinary student surgical laboratories. PROCEDURES Blood samples were obtained before and at completion of surgery.

Iodine speciation in dog foods and treats by high performance liquid chromatography with inductively coupled plasma mass spectrometry detection.

An analytical method for determination of the iodine species 3-monoiodotyrosine (MIT), iodide, 3,5-diiodotyrosine (DIT), 3,5-diiodothyronine (3, 5-T2), 3,5,3'-triiodothyronine (T3), and thyroxine (T4) in dog foods and treats is reported. Iodine speciation was carried out using a HPLC method capable of both anion-exchange and reversed-phase retention coupled with inductively coupled plasma mass spectrometry detection (LC-ICP-MS). The method was evaluated by the analysis of the iodine species concentrations in twelve dog foods and treats following enzymatic digestion.

Serum aldosterone and cortisol concentrations before and after suppression with fludrocortisone in cats: a pilot study.

Primary hyperaldosteronism is an increasingly recognized syndrome in cats, and diagnosis can be difficult. A potential diagnostic method has been reported, utilizing oral fludrocortisone administered twice daily for 4 days followed by collection of urine. In the current study, we sought to determine if blood sampling and a shorter dosing period would provide a possible means to test for primary hyperaldosteronism.

Exogenous thyrotoxicosis in dogs attributable to consumption of all-meat commercial dog food or treats containing excessive thyroid hormone: 14 cases (2008-2013).

Objective: To describe findings in dogs with exogenous thyrotoxicosis attributable to consumption of commercially available dog foods or treats containing high concentrations of thyroid hormone.

Design: Retrospective and prospective case series.

Animals: 14 dogs.

Amino acid differences in cat adrenocorticotropin account for the inability of a human-based immunoradiometric assay to detect the molecule in cat plasma.

A commercial immunoradiometric assay kit designed for the measurement of endogenous adrenocorticotropin (ACTH) concentrations in human plasma does not detect the molecule in plasma samples from cats. It was hypothesized that the inability of the assay to detect the molecule was related to variation(s) in the amino acid sequence of cat ACTH, compared with human ACTH. Cat ACTH complementary DNA was cloned from pituitary tissue and sequenced.

Inoculation of dogs with a recombinant ACTH vaccine.

Objective: To determine whether inoculation of healthy dogs with a recombinant peptide containing 3 copies of ACTH would result in the production of antibodies against ACTH and whether this would affect pituitary-adrenocortical function.

Animals: 8 healthy dogs.

Procedures: A recombinant peptide consisting of 3 copies of ACTH fused to a T-helper cell epitope was produced in Escherichia coli.

Validation of a low-dose adrenocorticotropic hormone stimulation test in healthy neonatal foals.

Objective: To determine the lowest ACTH dose that would induce a significant increase in serum cortisol concentration and identify the time to peak cortisol concentration in healthy neonatal foals.

Design: Prospective randomized crossover study.

Animals: 11 healthy neonatal foals.

Seasonal variation in results of diagnostic tests for pituitary pars intermedia dysfunction in older, clinically normal geldings.

Objective: To determine whether seasonal variations exist in endogenous plasma ACTH, plasma α-melanocyte-stimulating hormone (α-MSH), serum cortisol, and serum insulin concentrations and in the results of a dexamethasone suppression test for older, clinically normal geldings in Alabama.

Design: Cohort study.

Animals: 15 healthy mixed-breed geldings (median age, 14 years).

Validation of a low-dose ACTH stimulation test in healthy adult horses.

Objective: To determine the lowest ACTH dose that would induce a maximum increase in serum cortisol concentration in healthy adult horses and identify the time to peak cortisol concentration.

Design: Evaluation study.

Animals: 8 healthy adult horses.

Acute inhibition of carboxypeptidase E expression in AtT-20 cells does not affect regulated secretion of ACTH.

Carboxypeptidase E (CPE) is an exopeptidase that removes C-terminal basic amino acids from a variety of bioactive peptides. In addition to this role, data obtained in recent years has supported a potential function for CPE as a sorting receptor, helping direct peptides destined for regulated secretion from the trans-Golgi to granules in preparation for release. This possible sorting function was assessed using mouse AtT-20 cells, a well-established corticotroph cell line that synthesizes and releases POMC/ACTH in regulated fashion.

Effect of glucocorticoid administration on serum aldosterone concentration in clinically normal dogs.

Objective: To evaluate the effects of oral administration of anti-inflammatory dosages of prednisone for 28 days on serum aldosterone, cortisol, and electrolyte concentrations in clinically normal dogs.

Animals: 10 dogs.

Procedures: On days 1 through 28, 5 dogs received prednisone (0.

Prenylated Rab acceptor domain family member 1 is involved in stimulated ACTH secretion and inhibition.

Dexamethasone (Dex) inhibits stimulated adrenocorticotrophic hormone (ACTH) secretion in AtT-20 cells, a mouse corticotroph tumor cell line. Dexras1 protein expression is induced in corticotrophs by Dex. The function of Dexras1 is unknown; however, it may be involved in corticotrophic negative feedback.

Comparative analysis of Xenopus tropicalis hepcidin I and hepcidin II genes.

Hepcidin is an antimicrobial peptide and an iron-regulatory hormone that is conserved in fish, amphibians, and mammalians. Here we report the genomic and biochemical characterization of two amphibian hepcidins (tHEP1 and tHEP2) from the Western clawed frog (Xenopus tropicalis). Similar to fish and mammalian hepcidins, both tHEP1 and tHEP2 genes contain three exons and two introns.

Pituitary-adrenal function in dogs with acute critical illness.

Objective: To evaluate pituitary-adrenal function in critically ill dogs with sepsis, severe trauma, and gastric dilatation-volvulus (GDV).

Design: Cohort study.

Animals: 31 ill dogs admitted to an intensive care unit (ICU) at Washington State University or the University of Pennsylvania; all dogs had acute critical illness for < 48 hours prior to admission.

Genetic inactivation of p62 leads to accumulation of hyperphosphorylated tau and neurodegeneration.

The signaling adapter p62 plays a coordinating role in mediating phosphorylation and ubiquitin-dependent trafficking of interacting proteins. However, there is little known about the physiologic role of this protein in brain. Here, we report age-dependent constitutive activation of glycogen synthase kinase 3beta, protein kinase B, mitogen-activated protein kinase, and c-Jun-N-terminal kinase in adult p62(-/-) mice resulting in hyperphosphorylated tau, neurofibrillary tangles, and neurodegeneration.