Diagnosis and Long-term Treatment of Suspected Congenital Hypothyroidism in a Pigeon (Columba livia domestica).

An approximately 6-month-old domestic pigeon (Columba livia domestica) was presented for lethargy and an inability to perform its first molt. The pigeon was obese, had anatomical characteristics of a chick, including cere and plumage, and had a ventral coelomic soft tissue mass. Initial blood work was unremarkable. A computed tomographic scan confirmed excessive fat deposition in the coelom and a mass adherent to the liver. A fine-needle aspirate of the mass indicated fat accumulation. A thyroid-stimulating hormone (TSH) test was planned for this pigeon and 3 presumed euthyroid pigeons. Each pigeon was administered 80 µg (∼230 µg/kg) of recombinant human TSH. Blood was drawn at time 0 and 3 and 6 hours after administration of recombinant human TSH. Plasma total thyroxine (TT4) was measured in duplicate with an in-house analyzer and a reference laboratory. After recombinant human TSH administration, healthy pigeons showed a 4- to 21-fold increase in TT4, whereas the hypothyroid pigeon had all values <0.12 µg/dL. The pigeon was prescribed 20 µg of compounded levothyroxine twice daily. In the following months, the pigeon molted and developed adult features. The ventral coelomic soft tissue mass disappeared and repeated computed tomography scans showed a decreased amount of body fat and a reduction in the size of the coelomic mass. Levothyroxine was further adjusted multiple times according to additional TT4 testing to a dose of 2.5 µg once daily. The pigeon has been under treatment with levothyroxine for more than 2 years. Here we present the first reported case of confirmed hypothyroidism in a pigeon. Diagnosis with a TSH stimulation test was unequivocal, even when only considering the results of the in-house analyzer. Levothyroxine treatment resolved clinical signs and could be titrated to an appropriate dose.

Serum steroid and thyroid hormone concentrations in healthy domestic male and female alpacas.

Alpacas are high quality fiber producing animals, kept for production purpose and as pets. Endocrine imbalances from adrenal glands, gonads, or thyroid gland may result in coat abnormalities in domestic animals and affect reproduction. Contrary to many domesticated animals, information on hormone concentrations in alpacas is scarce. The purpose of this study was to provide steroid and thyroid hormone values in domestic alpacas. Blood was collected from healthy male (35 intact, 2 castrated) and female (48 non-pregnant, 3 pregnant) alpacas from local farms in Tennessee. Adrenal, reproductive, and thyroid hormones were analyzed. There were no significant differences in median concentrations of progesterone, estradiol, thyroxine (T4), and triiodothyronine (T3) between intact male and female non-pregnant alpacas. Median concentrations of testosterone, androstenedione, 17-hydroxyprogesterone, and cortisol were significantly higher in intact male alpacas compared to female non-pregnant alpacas. This information provides adrenal, gonadal, and thyroid hormone concentrations in alpacas to help with diagnosis of endocrine disorders.

Comparison of steroid and thyroid hormone concentrations in blood serum and plasma of captive tigers.

Analysis of steroid and thyroid hormones is often performed in blood serum. Occasionally though, plasma samples are submitted in lieu of serum for exotic species such as tigers. However, blood tube anticoagulants may affect hormone values. We compared serum and heparin plasma results for 7 hormones in tigers. Serum and plasma samples were collected from 25 tigers and analyzed for progesterone, 17-hydroxyprogesterone, cortisol, androstenedione, testosterone, estradiol, and thyroxine. Using Lin concordance correlation, serum and heparin plasma measures agreed for all hormones except cortisol. However, Passing-Bablok regression only found agreement between serum and heparin plasma measures for androstenedione, testosterone, and estradiol. Median values between the 2 sample types were significantly (p < 0.05) different for progesterone, 17-hydroxyprogesterone, cortisol, and thyroxine. Our results suggest that, for the aforementioned hormones, serum and heparin plasma values may not always be comparable.

Blood steroid concentrations in domestic Mongolian horses.

Traditionally, analysis of blood cortisol alone has been used to evaluate adrenal function. Currently, multisteroid analyses are considered more informative than analysis of a single hormone to assess adrenal function. The objective of the present research was to create a database for steroid reference values for domestic Mongolian horses. Seven adrenal steroid levels were determined in the blood of 18 colts, 34 stallions, 25 geldings, 17 fillies, and 29 mares. Results were as follows (lowest and highest group median, in nanograms per milliliter): progesterone: <0.030 (fillies), 4.30 (mares), and 0.070 (all horses); 17-OH-progesterone: 0.070 (colts), 0.520 (mares), and 0.110 (all horses); androstenedione: 0.101 (colts), 0.256 (stallions), and 0.181 (all horses); testosterone: <0.040 (mares, stallions, and fillies), 0.040 (geldings and colts), and <0.40 (all horses); estradiol: 0.066 (stallions), 0.093 (fillies), and 0.085 (all horses); cortisol: 23.040 (colts), 70.210 (geldings), and 50.770 (all horses); and aldosterone: 0.018 (colts), 0.297 (geldings), and 0.191 (all horses). Overall medians indicate that cortisol (98.70%) is the predominant steroid, followed by aldosterone (0.37%), androstenedione (0.35%), 17-OH-progesterone (0.21%), estradiol (0.17%), progesterone (0.14%), and testosterone (0.06%). This information provides adrenal and gonadal steroid reference concentrations to assist in physiological characterization and diagnosis of endocrine disorders in domestic Mongolian horses.

Effects of leuprolide acetate on selected blood and fecal sex hormones in Hispaniolan Amazon parrots (Amazona ventrais).

The luteinizing hormone-releasing hormone agonist leuprolide acetate is used commonly to anage reproductive problems in pet birds. To determine the effect of leuprolide acetate on plas a and fecal hormone levels in a psittacine species, a single 800 microg/kg dose of the 30-day depot form of leuprolide acetate was administered IM in 11 healthy, nonbreeding adult Hispaniolan Amazon parrots (Amazona ventralis), and plasma and fecal hormone levels were measured before and after leuprolide administration. At pooled baseline to 21 days postleuprolide acetate administration, sample collection day was significantly associated with plasma 17beta-estradiol and androstenedione levels and fecal 17beta-estradiol levels (evaluated in females only). Both plasma androstenedione and plasma 17beta-estradiol levels decreased significantly from baseline to a nadir at 7 days postleuprolide acetate administration but did not differ significantly 14 days later from that nadir or from pooled baseline samples, suggesting that the effect of leuprolide on hormone levels remained about 2 weeks. Fecal 17beta-estradiol levels increased significantly from the nadir at 7 days postleuprolide to 21 days postleuprolide administration, with trends of the level at 21 days postleuprolide being higher than the pooled baseline level and of decreasing levels from pooled baseline to 7 days postleuprolide administration. Plasma luteinizing hormone and fecal testosterone levels did not change significantly from baseline levels after leuprolide administration over the 2-day period. No significant correlations were found between plasma hormone and fecal hormone levels. These results suggest that measurement of plasma androstenedione, plasma 17beta-estradiol, and fecal 17beta-estradiol levels might be useful in assessing the effects of 30-day depot leuprolide acetate in Hispaniolan Amazon parrots.

Cortisol, progesterone, 17α-hydroxyprogesterone, and TSH responses in dogs injected with low-dose lipopolysaccharide.

BACKGROUND: Stress and diseases such as endotoxemia induce cortisol synthesis through a complex biosynthetic pathway involving intermediates (progesterone, and 17α-hydroxyprogesterone (17α-OHP)) and suppression of the hypothalamus-pituitary-thyroid axis. OBJECTIVE: To measure plasma concentrations of cortisol, progesterone, 17α-OHP, and thyroid stimulating hormone (TSH) in dogs experimentally injected with intravenous low-dose lipopolysaccharide (LPS). Our hypothesis was that LPS treatment would elicit a significant increase in cortisol and its precursors, and a significant decrease in TSH concentration. METHODS: Hormone measurements were performed on blood samples left over from a previous investigation (2011) on the effect of low-dose LPS on hematological measurands. Five sexually intact female dogs, none in estrous at the time of the study, were administered saline treatment two weeks prior to LPS treatment. LPS was administered intravenously at a dose of 0.1 µg/kg. Blood was collected before (baseline, time -24 hours) and 3-, 6- and 24-hours post-injection. Mixed model analysis for repeated measures was used, with both treatment and time as the repeated factors. Ranked transformation were applied when diagnostic analysis exhibited violation of normality and equal variance assumptions. Post hoc multiple comparisons were performed with Tukey's adjustment. Statistical significance was defined as p < 0.05. RESULTS: Significant differences relative to baseline values were detected following both treatments. Compared to baseline, dogs had significantly higher cortisol and 17α-OHP at 3-hours, and significantly lower TSH at 3- and 6-hours following LPS treatment. Dogs had significantly lower TSH at 6- and 24- following saline treatment. Though not statistically significant, the trend in progesterone concentrations was similar to cortisol and 17α-OHP, with an increase at 3-hours post-injection followed by a decrease close to baseline following both LPS and saline. Cortisol and 17α-OHP concentrations were higher after LPS treatment than after saline treatment at 3- and 6-hours post-injection, but differences were not statistically significant, and no significant differences between treatments were detected for any other hormone or timepoint. DISCUSSION AND CONCLUSION: Cortisol and its adrenal precursors are released in the bloodstream following a low dose of LPS, while TSH appears to decrease. Similar changes occurred following saline treatment, suggesting that even routine handling and saline injection in conditioned dogs can elicit alterations in the internal equilibrium with subsequent modification of both hypothalamus-pituitary-adrenal and thyroid axes. Changes to adrenal and thyroid hormone concentrations must be interpreted in light of clinical information. Further studies are needed to elucidate mechanisms of adrenal steroidal hormone synthesis and secretion in response to various stressful stimuli in both neutered and intact animals.

Variability of serum aldosterone concentrations in pet ferrets (Mustela putorius furo).

OBJECTIVE To explore sources of serum aldosterone concentration variability in a population of healthy and diseased ferrets, determine a preliminary 1 -sided reference interval for serum aldosterone concentration in healthy ferrets, and identify a decision limit to differentiate healthy from diseased ferrets on the basis of serum aldosterone concentration. DESIGN Prospective threshold definition and diagnostic accuracy study. ANIMALS 78 healthy (n = 56) and diseased (22) ferrets. PROCEDURES Serum aldosterone concentrations were measured on consecutively admitted ferrets, and an upper reference limit for aldosterone concentrations was established. Sensitivity and specificity of aldosterone concentration cutoffs to differentiate healthy from diseased ferrets were estimated with receiver operating characteristic curve analysis. RESULTS Measurements of serum aldosterone concentrations in the ferrets showed wide variability, with a median concentration of 4.75 pg/mL (interquartile range, 0.55 to 17.9 pg/mL; range, 0.02 to 283.9 pg/mL) and 76% (59/78) of samples having concentrations < 18 pg/mL. Ferrets that were healthy, older, or sexually inactive had significantly lower aldosterone concentrations. The upper limit of the reference interval for healthy ferrets was 13.3 pg/mL (90% confidence interval, 9.9 to 16.9 pg/mL). Analysis of receiver operating characteristic curves indicated that an aldosterone concentration cutoff value of 7.6 pg/mL differentiated healthy ferrets from diseased ferrets with a sensitivity of 72.7% and specificity of 73.2% (area under the curve, 0.79; 95% confidence interval, 0.67 to 0.91). CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that high aldosterone concentrations should not be considered diagnostic of primary hyperaldosteronism in ferrets. A need exists to develop better tests to identify primary hyperaldosteronism.

Analytic performance evaluation of a veterinary-specific ELISA for measurement of serum cortisol concentrations of dogs.

OBJECTIVE To investigate the precision of an ELISA for measurement of serum cortisol concentration (SCC) in dogs, assess agreement between this ELISA and 2 validated chemiluminescence assays (CLAs), and evaluate the clinical implications of any bias associated with this ELISA when measuring SCC in dogs. DESIGN Evaluation study. SAMPLE 75 stored, frozen serum samples from client-owned dogs. PROCEDURES Enzyme-linked immunosorbent assay precision was evaluated by measuring SCC of pooled serum samples. Agreement with standard methods was evaluated with Spearman rank correlation, Passing-Bablok regression, and Bland-Altman analysis to compare SCCs obtained with the ELISA and the 2 CLAs. An error grid was used to evaluate identified bias. RESULTS Within-laboratory coefficients of variation for pooled serum samples with low, medium, and high SCCs were 21.4%, 28.9%, and 13.0%, respectively. There was a high correlation between ELISA results (for all samples combined) and results of the 2 CLAs (CLA 1, r = 0.96; CLA 2, r = 0.97), but constant and proportional biases between the ELISA and CLAs were present at all concentrations. Clinically important disagreement between ELISA results and CLA results occurred in 16 of 63 (25%) samples, particularly with low and high SCCs. CONCLUSIONS AND CLINICAL RELEVANCE Results suggested that the rate of clinical disagreement between the ELISA and CLAs was sufficiently high to recommend that equivocal results obtained with the ELISA be confirmed by a reference laboratory. Further evaluation of analytic performance of the ELISA should focus on samples with very high and very low SCCs.

Adrenocortical Challenge Response and Genomic Analyses in Scottish Terriers With Increased Alkaline Phosphate Activity.

Scottish terriers (ST) frequently have increased serum alkaline phosphatase (ALP) of the steroid isoform. Many of these also have high serum concentrations of adrenal sex steroids. The study's objective was to determine the cause of increased sex steroids in ST with increased ALP. Adrenal gland suppression and stimulation were compared by low dose dexamethasone (LDDS), human chorionic gonadotropin (HCG) and adrenocorticotropic hormone (ACTH) response tests. Resting plasma pituitary hormones were measured. Steroidogenesis-related mRNA expression was evaluated in six ST with increased ALP, eight dogs of other breeds with pituitary-dependent hyperadrenocorticism (HAC), and seven normal dogs. The genome-wide association of single nucleotide polymorphisms (SNP) with ALP activity was evaluated in 168 ST. ALP (reference interval 8-70 U/L) was high in all ST (1,054 U/L) and HAC (985 U/L) dogs. All HAC dogs and 2/8 ST had increased cortisol post-ACTH administration. All ST and 2/7 Normal dogs had increased sex steroids post-ACTH. ST and Normal dogs had similar post-challenge adrenal steroid profiles following LDDS and HCG. Surprisingly, mRNA of hydroxysteroid 17-beta dehydrogenase 2 (HSD17B2) was lower in ST and Normal dogs than HAC. HSD17B2 facilities metabolism of sex steroids. A SNP region was identified on chromosome 5 in proximity to HSD17B2 that correlated with increased serum ALP. ST in this study with increased ALP had a normal pituitary-adrenal axis in relationship to glucocorticoids and luteinizing hormone. We speculate the identified SNP and HSD17B2 gene may have a role in the pathogenesis of elevated sex steroids and ALP in ST.

Physiologic assessment of blood glucose homeostasis via combined intravenous glucose and insulin testing in horses.

OBJECTIVE: To characterize the physiologic response to i.v. bolus injection of glucose and insulin for development of a combined glucose-insulin test (CGIT) in horses. ANIMALS: 6 healthy mares and 1 mare each with pituitary adenoma and urolithiasis. PROCEDURE: Horses were given a CGIT (glucose, 150 mg/kg; insulin, 0.1 U/kg); results were compared with a singular i.v. glucose tolerance test (GTT; 150 mg/kg) and a singular i.v. insulin sensitivity test (IST; 0.1 U/kg). Healthy horses were also given a CGIT after receiving xylazine and undergoing stress. RESULTS: Physiologically, the CGIT resulted in a 2-phase curve with positive (hyperglycemic) and negative (hypoglycemic) portions; the positive phase came first (250% of baseline at 1 minute). The descending segment declined linearly to baseline by approximately 30 minutes and to a nadir at 58% of baseline by 75 minutes. After a 35-minute valley, a linear ascent to baseline began. Addition of insulin in the CGIT increased glucose utilization by approximately 4.5 times during the positive phase but not during the negative phase. The diseases' effects and experimental inhibition of insulin secretion with xylazine and stress were detectable by use of the 2 phases of the CGIT. Only a single positive phase resulted from the GTT and a single negative phase from the IST CONCLUSIONS AND CLINICAL RELEVANCE: The CGIT resulted in a consistent, well-defined glycemia profile, which can be disrupted experimentally or by a disease process. The CGIT has clinical potential because it provides integrated information and more information than either the singular GTT or IST.

Early life triclocarban exposure during lactation affects neonate rat survival.

Triclocarban (3,4,4'-trichlorocarbanilide; TCC), an antimicrobial used in bar soaps, affects endocrine function in vitro and in vivo. This study investigates whether TCC exposure during early life affects the trajectory of fetal and/or neonatal development. Sprague Dawley rats were provided control, 0.2% weight/weight (w/w), or 0.5% w/w TCC-supplemented chow through a series of 3 experiments that limited exposure to critical growth periods: gestation, gestation and lactation, or lactation only (cross-fostering) to determine the susceptible windows of exposure for developmental consequences. Reduced offspring survival occurred when offspring were exposed to TCC at concentrations of 0.2% w/w and 0.5% w/w during lactation, in which only 13% of offspring raised by 0.2% w/w TCC dams survived beyond weaning and no offspring raised by 0.5% w/w TCC dams survived to this period. In utero exposure status had no effect on survival, as all pups nursed by control dams survived regardless of their in utero exposure status. Microscopic evaluation of dam mammary tissue revealed involution to be a secondary outcome of TCC exposure rather than a primary effect of compound administration. The average concentration of TCC in the milk was almost 4 times that of the corresponding maternal serum levels. The results demonstrate that gestational TCC exposure does not affect the ability of dams to carry offspring to term but TCC exposure during lactation has adverse consequences on the survival of offspring although the mechanism of reduced survival is currently unknown. This information highlights the importance of evaluating the safety of TCC application in personal care products and the impacts during early life exposure.

Clinical features of progressive vacuolar hepatopathy in Scottish Terriers with and without hepatocellular carcinoma: 114 cases (1980-2013).

OBJECTIVE: To characterize signalment, clinical features, clinicopathologic variables, hepatic ultrasonographic characteristics, endocrinologic profiles, treatment response, and age at death of Scottish Terriers with progressive vacuolar hepatopathy (VH) with or without hepatocellular carcinoma (HCC). DESIGN: Retrospective case series. ANIMALS: 114 Scottish Terriers with progressive VH. PROCEDURES: Electronic databases from 1980 to 2013 were searched for adult (age > 1 year) Scottish Terriers with histopathologic diagnoses of diffuse glycogen-like VH. Available sections of liver specimens were histologically reevaluated to confirm diffuse VH with or without HCC; 8 dogs with HCC only had neoplastic tissue available. Physical examination, clinicopathologic, treatment, and survival data were obtained. RESULTS: 39 of 114 (34%) dogs with VH had HCC detected at surgery or necropsy or by abdominal ultrasonography. Histologic findings indicated that HCC was seemingly preceded by dysplastic hepatocellular foci. No significant differences were found in clinicopathologic variables or age at death between VH-affected dogs with or without HCC. Fifteen of 26 (58%) dogs with high hepatic copper concentrations had histologic features consistent with copper-associated hepatopathy. Although signs consistent with hyperadrenocorticism were observed in 40% (46/114) of dogs, definitive diagnosis was inconsistently confirmed. Assessment of adrenal sex hormone concentrations before and after ACTH administration identified high progesterone and androstenedione concentrations in 88% (22/25) and 80% (20/25) of tested dogs, respectively. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that VH in Scottish Terriers may be linked to adrenal steroidogenesis and a predisposition to HCC. In dogs with VH, frequent serum biochemical analysis and ultrasonographic surveillance for early tumor detection are recommended.

Use of recombinant human thyroid-stimulating hormone for evaluation of thyroid function in guinea pigs (Cavia porcellus).

OBJECTIVE: To evaluate the effects of administration of recombinant human (rh) thyroid-stimulating hormone (TSH) for evaluation of thyroid function in euthyroid guinea pigs (Cavia porcellus). DESIGN: Prospective, experimental study. ANIMALS: 10 healthy, sexually intact, pet guinea pigs (approx 1 year of age). PROCEDURES: Guinea pigs were given rhTSH (100 µg, IM); plasma thyroxine concentrations were determined prior to and 3 and 4 hours after rhTSH injection. The animals were housed in 2 groups on the basis of sex and fed different commercial maintenance diets according to their husbandry. RESULTS: There was no significant difference in thyroxine concentrations between males and females before or after rhTSH injection. There was also no difference between thyroxine concentrations at 3 versus 4 hours after rhTSH injection. There was a significant difference between thyroxine concentrations before (median, 9.05 nmol/L [0.70 µg/dL]; 10% to 90% range, 7.39 to 16.99 nmol/L [0.57 to 1.32 µg/dL]) and after (mean ± SD, 23.95 ± 4.2 nmol/L) rhTSH injection. Euthyroid guinea pigs had plasma thyroxine concentrations of at least 7.30 nmol/L (0.57 µg/dL) and an increase of at least 2.6 times prestimulation thyroxine concentrations at 3 or 4 hours after stimulation. CONCLUSIONS AND CLINICAL RELEVANCE: The results suggested that rhTSH administered IM can be used for the TSH stimulation testing in guinea pigs. We suggest thyroxine concentration in a euthyroid guinea pig should at least double 3 to 4 hours after rhTSH injection.

Use of recombinant human thyroid-stimulating hormone for thyrotropin stimulation testing in euthyroid ferrets.

OBJECTIVE: To evaluate the effects of IM administration of recombinant human thyroid-stimulating hormone (rhTSH) on plasma total thyroxine (T4) concentrations in euthyroid ferrets. DESIGN: Evaluation study. ANIMALS: 25 healthy neutered ferrets (14 female and 11 male) of various ages from 2 populations (laboratory ferrets from Georgia and pet ferrets from Pennsylvania). PROCEDURES: Each ferret underwent a physical examination and standard hematologic testing to ensure it was healthy and had clinically normal thyroid function. Once determined to be euthyroid, ferrets received a single IM injection of 100 µg of rhTSH. Blood samples were collected into plasma-separator tubes immediately before the rhTSH injection (time 0) and 4 hours after injection to measure T4 concentrations. RESULTS: Males did not differ from females in regard to prestimulation or poststimulation plasma T4 concentrations; however, prestimulation and poststimulation T4 concentrations were significantly different between the 2 groups of ferrets. A significant difference was also identified between prestimulation T4 concentration (mean ± SD, 21.3 ± 6.1 nmol/L) and poststimulation T4 concentration (29.9 ± 8.2 nmol/L). All 25 ferrets had high poststimulation T4 concentrations (median difference, 7. 5 nmol/L; 10% to 90% interval, 3.26 to 17.70 nmol/L [0.25 to 1.38 µg/dL]; range, 2.50 to 20.70 nmol/L [0.19 to 1.61 µg/dL]); this represented a median increase in T4 concentration of 35% (10% to 90% interval, 18% to 81%; range, 8% to 126%). CONCLUSIONS AND CLINICAL RELEVANCE: Results suggested that rhTSH can be used for thyrotropin stimulation testing in ferrets when administered IM. According to the findings, a euthyroid ferret should have an increase of approximately 30% in plasma T4 concentration 4 hours after rhTSH injection.

Evaluation of the efficacy and safety of single administration of 4.7-mg deslorelin acetate implants on egg production and plasma sex hormones in Japanese quail (Coturnix coturnix japonica).

OBJECTIVE: To evaluate the effects of 4.7-mg deslorelin acetate implants on egg production and plasma concentrations of 17ß-estradiol and androstenedione in Japanese quail (Coturnix coturnix japonica) over 180 days and assess safety of the implants in quail via gross and histologic examination. ANIMALS: 20 female Japanese quail. PROCEDURES: Following a 7-day period of consistent egg laying, quail were anesthetized and received a 4.7-mg deslorelin implant (treatment group; n = 10) or identical placebo implant (control group; 10) SC between the scapulae. Egg production was monitored daily. Plasma concentrations of 17ß-estradiol and androstenedione were measured on days 0 (immediately prior to implant injection), 14, 29, 62, 90, 120, 150, and 180 via radioimmunoassay. Birds were weighed periodically and euthanized at day 180 for complete necropsy. RESULTS: Egg production was significantly decreased in the treatment group, compared with the control group, from 2 to 12 weeks after implant injection. Egg production ceased in 6 of 10 quail in the treatment group (mean duration of cessation, 70 days). Plasma androstenedione and 17ß　-estradiol concentrations were significantly lower on day 29 in the treatment group than in the control group. On day 180, 17ß　-estradiol concentration was lower in control than in treated birds.No clinically relevant lesions were detected in either group at necropsy [corrected]. CONCLUSIONS AND CLINICAL RELEVANCE: 4.7-mg deslorelin acetate implants reversibly decreased egg laying for approximately 70 days in most of the Japanese quail evaluated. Further studies evaluating implants containing different concentrations of the drug are needed in quail and other avian species.

Effect of combined lignan phytoestrogen and melatonin treatment on secretion of steroid hormones by adrenal carcinoma cells.

OBJECTIVE: To investigate the in vitro effect of the combination of lignan enterolactone (ENL) or lignan enterodiol (END) with melatonin on steroid hormone secretion and cellular aromatase content in human adrenal carcinoma cells. SAMPLE: Human adrenocortical carcinoma cells. PROCEDURES: Melatonin plus ENL or END was added to cell culture medium along with cAMP (100µM); control cells received cAMP alone. Medium and cell lysates were collected after 24 and 48 hours of cultivation. Samples of medium were analyzed for progesterone, 17-hydroxyprogesterone, androstenedione, aldosterone, estradiol, and cortisol concentration by use of radioimmunoassays. Cell lysates were used for western blot analysis of aromatase content. RESULTS: The addition of ENL or END with melatonin to cAMP-stimulated cells (treated cells) resulted in significant decreases in estradiol, androstenedione, and cortisol concentrations at 24 and 48 hours, compared with concentrations in cells stimulated with cAMP alone (cAMP control cells). The addition of these compounds to cAMP-stimulated cells also resulted in higher progesterone and 17-hydroxyprogesterone concentrations than in cAMP control cells; aldosterone concentration was not affected by treatments. Compared with the content in cAMP control cells, aromatase content in treated cells was significantly lower. CONCLUSIONS AND CLINICAL RELEVANCE: The combination of lignan and melatonin affected steroid hormone secretion by acting directly on adrenal tumor cells. Results supported the concept that this combination may yield similar effects on steroid hormone secretion by the adrenal glands in dogs with typical and atypical hyperadrenocorticism.

Comparison of testis structure, function and thyroid hormone levels in control C57BL/6 mice and anti-mullerian hormone over expressing mice.

Anti-Mullerian hormone (AMH) is considered as a negative regulator of postnatal Leydig cell (LC) differentiation, because AMH over expressing mice (Mt-hAMH mice) testes are deficient in LC. Therefore, in the present study Mt-hAMH mice was used as a model to examine the process of postnatal LC differentiation. Testis structure-function studies were performed in age-matching Mt-hAMH and C57BL/6 (controls) mice; testicular components were quantified and circulating testosterone and thyroid hormone levels (thyroxine/T4 and triiodothyronine/T3; necessary for postnatal LC differentiation) were determined. Results revealed that Mt-hAMH mice were heavier and their testis weights were smaller compared to controls. Mast cells were present in Mt-AMH testis interstitium, but absent in controls. The absolute volumes of seminiferous tubules (ST), testis interstitium, LC and blood vessels per testis were lower and lymphatic space was higher in Mt-hAMH mice than in controls (p<0.05). The average cell LC volume and their number per testis, ST length, plasma testosterone, luteinizing hormone-stimulated testosterone secretion per testis and per LC in vitro, plasma T4 and T3 were significantly lower in Mt-hAMH mice compared to controls (p<0.05). Increased body weight in Mt-hAMH mice could be attributed to the reduced T4 and T3. Reduced testis weight in Mt-AMH mice is explained by the reduced ST volume in them. Reduced plasma testosterone, testicular and LC testosterone secretion in vitro in Mt-hAMH mice can be explained by the reduced number, size and steroidogenic potential of LC in Mt-hAMH mice. Study revealed several structure-function deficiencies in Mt-AMH mouse compared to controls, which were not documented in previous investigations. As hypothyroidism causes arrest in postnatal LC differentiation, it is suggested that the reduced LC number in Mt-hAMH testes could be at least in part due to their reduced thyroid hormone levels. However, latter concept needs to be further tested in future investigations.

Inhibition of collagenase breakdown of equine corneas by tetanus antitoxin, equine serum and acetylcysteine.

OBJECTIVE: To determine whether tetanus antitoxin, equine serum, and acetylcysteine, which are currently used in the treatment of equine corneal ulcer, inhibit the digestion of equine corneal collagen when exposed to collagenase in vitro. ANIMALS STUDIED: Corneas from 40 adult horses. PROCEDURES: Sections of equine corneas were incubated with saline, a solution of bacterial collagenase in saline, bacterial collagenase in saline plus equine tetanus antitoxin, bacterial collagenase in saline plus equine serum, or bacterial collagenase in saline plus acetylcysteine. Each one of the collagenase inhibitors was tested at different concentrations. The degree of corneal collagen digestion was determined by concentrations of hydroxyproline released into the incubation media and/or by weight loss of the cornea. RESULTS: Corneas exposed to collagenase released a significant (0.05 level) large amount of hydroxyproline (43.1 +/- 2.3 microg/mL/100 mg cornea/5 h) and decreased cornea weight by up to 89%. Blood serum (200 microL/mL), purified albumin or globulin fractions of serum, tetanus antitoxin (120 units/mL), and acetylcysteine (20 mg/mL) when used at the highest concentrations blocked collagenase digestive activity by approximately 50%. Dilution of inhibitors decreased corneal protection and linearly increased corneal weight loss. Purified equine serum albumin and globulin fractions were equally effective in protecting corneas. CONCLUSIONS: This experiment indicates that tetanus antitoxin, serum and acetylcysteine equally protected corneas from collagenase digestion, in vitro. However, a clinical trial is needed to establish relative therapeutic value.

Differential modulation of signaling pathways and apoptosis of ras-transformed 10T1/2 cells by the depsipeptide FR901228.

(E)-(1S,4S,10S,21R)-7-[(Z)-ethylidene]-4,21-diisopropyl-2-oxa-12,13-dithia-5,8,20,23-tetraazabicyclo[8,7,6]-tricos-16-ene-3,6,9,19,22-pentanone (FR901228), a natural anticancer depsipeptide, induces apoptosis of ras-transformed 10T1/2 cells whereas it induces growth arrest of nontransformed counterpart cells in G0/G1 phase of the cell cycle. Our study of the effect of FR901228 treatment on intracellular signaling pathways reveals a discriminating activity of FR901228 to regulate signaling cascades differently in ras-transformed 10T1/2 cells and nontransformed counterpart cells. Induction of apoptosis of ras-transformed cells by FR901228 correlates with suppression of the extracellular signal-regulated kinase (ERK) signaling pathway through reduction of Raf expression and deactivation of Mek and Erk, inhibition of the phosphoinositide-3 kinase (PI3-K) pathway indexed by suppression of Akt activity, suppression of p38 activity, and activation of caspase-3. Expression of p21(Cip1) is not induced in ras-transformed cultures undergoing apoptosis induced by FR901228. In contrast, FR901228 induces p21(Cip1) expression in nontransformed counterpart cultures growth-arrested in G0/G1 that is also accompanied by moderate induction of the kinase activities of Raf, Mek, Erk, and Akt, but not accompanied by activation of caspase-3 or changes in p38 activity. Our study indicates a potential value of FR901228 in the treatment of cancer cells involving aberrant regulation of Ras through preferential induction of the caspase cascade and suppression of the ERK, PI3-K, and p38 pathways.