Changes in thyroid hormone concentrations over time in dogs with autoimmune thyroiditis.

Objective: The objective of this study was to follow long-term changes in the concentration of thyroid hormones in dogs with subclinical thyroiditis.

Samples: Samples were obtained from 125 dogs with subclinical thyroiditis. The study population included 70 female and 55 male dogs.

Case report: Androgen-secreting adrenocortical tumors in eight cats.

Urine marking, aggression, and other behavioral concerns are common reasons for cat owners to seek veterinary care. Empiric treatment for lower urinary tract disease or primary behavior disorders are commonly pursued, especially in those cases with normal routine laboratory evaluations. Herein, we report the clinicopathologic findings in eight sexually altered cats that were diagnosed with androgen-secreting adrenocortical tumors.

Investigation of the urine cortisol to creatinine ratio for the diagnosis of hypoadrenocorticism in dogs.

Objective: To evaluate the urine cortisol-to-creatinine ratio (UCCR) for the diagnosis of hypoadrenocorticism (HA) in dogs and to determine whether the method of urine cortisol measurement affects results.

Animals: 41 dogs with naturally occurring HA and 107 dogs with nonadrenal illness.

Procedures: Urine samples were prospectively collected from dogs undergoing testing for HA.

Retrospective study of aldosterone and progesterone secreting adrenal tumors in 10 cats.

Background: Primary hyperaldosteronism caused by adrenal neoplasia has been well described in cats. Multiple corticosteroid abnormalities occur in a subset of affected cats, but characterizations of this syndrome are limited to several case reports.

Objectives: To describe a series of cats with adrenal tumors secreting aldosterone and additional corticosteroids.

Multiple corticosteroid abnormalities in cats with hyperaldosteronism.

Background: The frequency with which multiple corticosteroid abnormalities occur in cats with aldosterone secreting adrenocortical tumors is unknown.

Objectives: To evaluate adrenal-derived corticosteroids in cats in which blood samples were submitted for measure of aldosterone.

Animals: Two hundred ninety-seven cats.

Low-dose desoxycorticosterone pivalate treatment of hypoadrenocorticism in dogs: A randomized controlled clinical trial.

Background: Desoxycorticosterone pivalate (DOCP) is a commonly used mineralocorticoid replacement for dogs with primary hypoadrenocorticism (HA), but manufacturer-recommended dosing protocols can be cost-prohibitive. Recent reports also have raised concerns that label dose protocols could be excessive.

Objective: To investigate the relative efficacy and adverse effects of 2 DOCP dosages in dogs with primary glucocorticoid and mineralocorticoid deficient HA.

Qualitative and semiquantitative assessment of thyroid hormone binding proteins in greyhounds and other dog breeds.

Total thyroxine (T4) concentrations are lower in healthy greyhounds compared to most other non-sighthound breeds. In humans, variations in the structure or concentration of the major thyroid hormone binding proteins are responsible for most reported differences between total T4 concentrations in healthy individuals from different ethnic groups or other subpopulations. The aim of this study was to determine if such variations are also responsible for the lower total T4 concentrations in greyhounds.

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.

The interpretive contribution of the baseline serum cortisol concentration of the ACTH stimulation test in the diagnosis of pituitary dependent hyperadrenocorticism in dogs.

Background: Current recommendation for performing the ACTH stimulation test (ACTHST) for diagnosis of hyperadrenocorticism (HAC) advocates the collection of baseline serum cortisol concentration (BC), but no references for interpretation of its results exist.

Objective: Evaluate the contribution of BC of the ACTHST to the diagnosis of HAC.

Animals: Fifty-four dogs were evaluated for suspected HAC at a referral hospital.

Radioactive iodine uptake in hyperthyroid cats after administration of recombinant human thyroid stimulating hormone.

Background: Radioactive iodine therapy is considered the treatment of choice for hyperthyroidism in cats, but the availability of this modality is limited by costs and hospitalization requirements. Administration of recombinant human thyroid stimulating hormone (rh-TSH) to humans with thyroid neoplasia or nodular goiter can increase thyroidal iodine uptake, thereby allowing the use of lower radioactive iodine doses for treatment. Veterinary studies of this subject are limited, and results are conflicting.

Association between hyperinsulinaemia and laminitis severity at the time of pituitary pars intermedia dysfunction diagnosis.

Background: Hyperinsulinaemia is the suspected component of insulin dysregulation having the strongest association with laminitis and occurs variably in equids with pituitary pars intermedia dysfunction (PPID).

Objectives: We hypothesised that magnitude of hyperinsulinaemia correlates with laminitis severity in PPID-affected equids. Furthermore, we hypothesised that owners can be unaware of chronic endocrinopathic laminitis.

Hematologic, Biochemical, and Endocrine Parameters in Horses With Tooth Resorption and Hypercementosis.

Background: Equine odontoclastic tooth resorption and hypercementosis (EOTRH) is a frequently diagnosed condition in adult horses. The underlying etiology is still unknown. Hematologic, biochemical, and endocrine values have not been reported in EOTRH-affected horses.

Thyrotoxicosis induced by excessive 3,5,3'-triiodothyronine in a dog.

CASE DESCRIPTION A 7-year-old castrated male Havanese was evaluated at a veterinary teaching hospital because of a 12-week history of hyperactivity, aggression, and progressive weight loss despite a healthy appetite. CLINICAL FINDINGS Tachycardia was the only remarkable finding during physical examination. Serum 3,5,3'-triiodothyronine (T3) and free T3 concentrations were markedly increased, and thyroxine (T4), free T4, and thyroid-stimulating hormone concentrations were at or decreased from the respective reference ranges.

Effects of Levothyroxine Administration and Withdrawal on the Hypothalamic-Pituitary-Thyroid Axis in Euthyroid Dogs.

Background: Chronic supplementation can suppress the hypothalamic-pituitary-thyroid axis (HPTA) and make it difficult to assess thyroid function after withdrawal of levothyroxine.

Objectives: To determine whether the HPTA is suppressed after levothyroxine administration in euthyroid dogs and the time required for resolution of any suppression.

Animals: Twenty-eight healthy euthyroid dogs.

Comparison of health parameters in normal cats fed a limited iodine prescription food vs a conventional diet.

Objectives The objective was to compare the effect on thyroid function in healthy, adult cats fed a limited-iodine food or conventional diet for 24 months. Methods Cats in the limited-iodine group (n = 14) were fed a commercial, dry food containing 0.2 ppm iodine on a dry-matter basis (DMB).

Evaluation of Basal Serum or Plasma Cortisol Concentrations for the Diagnosis of Hypoadrenocorticism in Dogs.

Background: Previous studies that included limited numbers of affected dogs have suggested basal cortisol concentrations ≤55 nmol/L (2 μg/dL) are sensitive, but nonspecific, for a diagnosis of hypoadrenocorticism. A detailed assessment of the diagnostic utility of basal cortisol concentrations is warranted.

Hypothesis/objectives: To evaluate the utility of basal cortisol concentrations for the diagnosis of hypoadrenocorticism in a large number of dogs, including those with and without serum electrolyte abnormalities.

Potential cutaneous hypersensitivity reaction to an inactive ingredient of thyroid hormone supplements in a dog.

Background: Although discussions about allergic reactions to thyroid supplements abound on professional forums, there is almost no information in the literature on these specific idiosyncratic drug reactions.

Animal: A dog with a history of hypothyroidism-associated weight gain and mild lethargy was prescribed levothyroxine tablets (0.018 mg/kg twice daily).

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.

Evaluation of thyroid-stimulating hormone, total thyroxine, and free thyroxine concentrations in hyperthyroid cats receiving methimazole treatment.

Background: Iatrogenic hypothyroidism (IH) after treatment of hyperthyroidism can impair renal function. No study compared the efficacy of measurement of serum free thyroxine by equilibrium dialysis (fT4ed) or thyroid-stimulating hormone (TSH) concentrations for monitoring cats receiving methimazole.

Objectives: To (1) compare the ability of total T4 and fT4ed concentrations in conjunction with TSH to define thyroid function in hyperthyroid cats receiving methimazole, (2) determine the prevalence of IH in cats receiving methimazole, and (3) examine the relationship between thyroid axis hormones and serum creatinine concentration.

Hypervitaminosis D and Metastatic Calcification in a Colony of Inbred Strain 13 Guinea Pigs, Cavia porcellus.

A commercial diet fed to a colony of inbred strain 13 guinea pigs for approximately 6 weeks was subsequently recalled for excessive levels of vitamin D. Twenty-one of 62 animals exhibited clinical signs, including anorexia, lethargy, and poor body condition. Nine affected and 4 clinically normal animals were euthanized for further evaluation, including serum chemistry, urinalysis, and gross and/or histopathology.

Serum concentrations of gastrin after famotidine and omeprazole administration to dogs.

Background: The duration of antacid-induced hypergastrinemia after cessation of administration of omeprazole and famotidine apparently has not been determined in dogs.

Hypothesis: That serum gastrin will return to basal concentrations by 7 days after cessation of famotidine or omeprazole administration.

Animals: Nine healthy, adult, male, research colony dogs.

Relationship among serum creatinine, serum gastrin, calcium-phosphorus product, and uremic gastropathy in cats with chronic kidney disease.

Background: Chronic kidney disease (CKD) in cats is associated with gastrointestinal signs commonly attributed to uremic gastropathy. Consequently, patients often are treated with antacids and gastrointestinal protectants. This therapeutic regimen is based on documented gastric lesions in uremic humans and dogs, but the nature and incidence of uremic gastropathy in cats are unknown.

Nonthyroidal illness syndrome in adult horses.

Background: This study was performed to determine whether sick horses have thyroid hormone (TH) alterations similar to those observed in nonthyroidal illness syndrome in other species.

Hypothesis: Horses suffering from systemic diseases have decreased THs and inappropriately low thyroid-stimulating hormone (TSH).

Animals: Seventy-one clinically normal horses; 380 hospitalized horses.

Relation of vitamin D status to congestive heart failure and cardiovascular events in dogs.

Background: Vitamin D plays a pivotal role in cardiac function, and there is increasing evidence that vitamin D deficiency is associated with the development of congestive heart failure (CHF) in people.

Hypothesis: Serum vitamin D concentration is lower in dogs with CHF compared with unaffected controls and serum vitamin D concentration is associated with clinical outcome in dogs with CHF.

Animals: Eighty-two client-owned dogs.

Effect of hypothyroidism on insulin sensitivity and glucose tolerance in dogs.

Objective: To determine the effects of hypothyroidism on insulin sensitivity, glucose tolerance, and concentrations of hormones counter-regulatory to insulin in dogs.

Animals: 8 anestrous mixed-breed bitches with experimentally induced hypothyroidism and 8 euthyroid control dogs.

Procedures: The insulin-modified frequently sampled IV glucose tolerance test and minimal model analysis were used to determine basal plasma insulin and glucose concentrations, acute insulin response to glucose, insulin sensitivity, glucose effectiveness, and disposition index.