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in Journal of the American Veterinary Medical Association
in Journal of the American Veterinary Medical Association

SUMMARY

A commercially available radioimmunoassay (ria) kit for measurement of human adrenocorticotropin (hacth) was validated for use in dogs. Assay sensitivity was 3 pg/ ml. Intra-assay coefficient of variation (× 100; cv) for 3 canine plasma pools was 3.0 (mean ± sd, 33 ± 0.99 pg/ ml), 4.2 (71 ± 2.4 pg/ml) and 3.7 (145 ± 3.7 pg/ml) %. Interassay cv for 2 plasma pools measured in 6 assays was 9.8 (37 ± 3.6 pg/ml) and 4.4 (76 ± 3.4 pg/ml) %, respectively. Dilutional parallelism was documented by assaying 2 pools of canine plasma at 3 dilutions and correcting the measured result for dilution. Corrected mean concentrations for the first pool were 33 (± 0.99), 36 (± 4.3), and 33 (± 6.8) pg/ml; corrected mean concentrations for the second pool were 145 (± 5.4), 141 (± 10.8) and 125 (± 3.4) pg/ml. Recovery of 1-39hacth added to canine plasma (6.25, 12.5, 25.0, 50.0, and 100.0 pg/ml) was linear and quantitative (slope = 0.890, R2 = 0.961). To test whether anticoagulant or the protease inhibitor, aprotinin, influences acth concentration in canine plasma, acth was measured in canine blood collected in 4 tubes containing anticoagulant: heparin (h), heparin + 500 kallikrein inhibitor units (KIU) of aprotinin/ml (ha), edta (e), and edta + aprotinin (ea). Plasma acth concentration was the same when samples containing h and ha, or ha and e were compared, and was significantly (P < 0.01) lower in samples containing ea. Plasma storage at - 20 C for 1 week or 1 month was not associated with significant change in acth concentration in canine plasma, using any of the 4 anticoagulant treatments. Plasma acth concentration measured after 6 months’ storage at —20 C was significantly (P < 0.01) lower for all anticoagulants used. Synthetic 1-39hacth added to canine blood was accurately recovered (88 to 109%, n = 3) from plasma containing edta, with or without aprotinin, whereas percentage recovery was overestimated by 18 to 91% in heparinized plasma. Plasma acth concentrations in edta- treated canine blood kept at 4 or 22 to 25 C for 15 to 90 minutes prior to centrifugation at 8 C were not significantly different. Plasma acth concentration in canine plasma was affected by storage tube material. Concentration of acth in canine plasma stored in borosilicate glass tubes for 1 week or 1 month at — 70 C was significantly higher than initial acth values (P ≤ 0.01), but was unchanged over time in plasma stored in polypro-pylene or polystyrene tubes.

Sample handling procedures affect canine plasma acth concentration measured by use of the ria kit. Optimal sample handling conditions for plasma acth measurement in dogs include use of edta anticoagulant, blood collected at 20 to 25 C (room temperature) followed by centrifugation within 15 to 90 minutes, and plasma storage in plastic (not glass) tubes for not longer than 1 month at −20 C.

Free access
in American Journal of Veterinary Research

Summary

Medical records of 15 dogs with vaginal septa, examined between April 1983 and December 1992, were reviewed. Overall prevalence of vaginal septation at the hospital during the study period was 0.03%. Thirteen breeds were represented; mean age at the time of initial examination was 2.4 years. Owners’ original complaints included inability to breed naturally, dysuria, urinary incontinence, infertility, recurrent vaginitis, ambiguous external genitalia, and dystocia. One dog did not have clinical signs associated with the vaginal septum. In 11 of the 15 dogs, the septum could be palpated during digital vaginal examination. The septum could be seen in 6 of the 7 dogs in which vaginoscopy was performed. Twelve of the 15 dogs underwent positive-contrast vaginography; in all 12, the septum could be easily seen. Four of the 15 dogs underwent removal of the septum, with or without episiotomy, and 4 others were ovariohysterectomized. One dog was bred by means of artificial insemination and became pregnant. The remaining 6 dogs were lost to follow-up.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective

To determine the effect of finasteride at dosages of 0.10, 0.25, and 0.50 mg/kg of body weight, PO, q 24 h, on serum concentrations of dihydrotestosterone (DHT) and testosterone (T) in clinically normal sexually intact adult male dogs.

Animals

3 intact adult male dogs less than 5 years old.

Procedure

Concentrations of DHT and T were measured by radioimmunoassay of serum from dogs randomly assigned to 1 of 3 treatment groups (0.10, 0.25, or 0.50 mg of finasteride/kg, PO, q 24 h, for 7 days) in a Latin square design with repeated measures. Blood was obtained before and on days 1, 2, 4, and 7 of treatment; 3 blood samples were obtained at 20 minute intervals to detect pulsatile secretion of DHT and T. Dogs were untreated at least 2 weeks between treatments.

Results

Finasteride at all doses was associated with a mean decrease in concentration of DHT of 55% (range, 155 ± 32.3 pg/ml to 70 ± 15 pg/ml), but had no effect on concentration of T (before treatment, 2.6 ± 0.38 ng/ml; after treatment, 2.2 ± 0.63 ng/ml).

Conclusions

Finasteride at these doses significantly decreased serum concentration of DHT in sexually intact adult male dogs. Concentrations of DHT and T before and 7 days after treatment did not differ by dosage of finasteride administered.

Clinical Relevance

Finasteride (5 mg; 1 tablet) may be a drug of choice for treatment of benign prostatic hypertrophy in 10- to 50-kg dogs. (Am J Vet Res 1998;59:762-764)

Free access
in American Journal of Veterinary Research

SUMMARY

To determine the effect of oral administration of prednisolone on thyroid function, 12 healthy Beagles were given 1.1 mg of prednisolone/kg of body weight every 12 hours for 22 days after 8 days of diagnostic testing of the dogs before treatment with prednisolone. Thyroid-stimulating hormone (tsh) and thyrotropin-releasing hormone (trh) response tests were performed before treatment (days 1 and 8 of the study) and during treatment (days 21 and 28 of the study). Blood samples were collected daily at 8 am and 2 and 8 pm to rule out normal daily hormone fluctuations as the cause of a potential decrease in serum triodothyronine (T3), thyroxine (T4), and free T4 (fT4) concentrations. Serum T3, T4, and fT4 concentrations before treatment and 1 day and 21 days after the first prednisolone dose were compared by analyses of variance. Post-tsh and -trh serum T3 and T4 concentrations before and during treatment were compared, using the Student t test for paired data. Oral administration of prednisolone significantly (P < 0.005) decreased serum T3, T4, and fT4 concentrations in the 8 am and 2 and 8 pm samples obtained 1 day and 21 days after the first prednisolone dose. Serum T4 and fT4 concentrations in 8 am and 2 pm samples were significantly (P < 0.05) lower 21 days after the first prednisolone dose than they were at 1 day after the first dose. Before treatment, serum T4 concentration in the 2 pm samples was significantly (P < 0.05) higher than serum T4 concentration in 8 am and 8 pm samples. Oral administration of prednisolone significantly (P < 0.01) decreased serum T3 and T4 concentrations 6 hours after tsh and trh injections. Significant difference in the mean incremental change in serum T3 and T4 concentrations was not observed when comparing before- and during-prednisolone treatment values for the trh response test. However, for the tsh response test, the mean incremental changes in serum T3 and T4 concentrations were significantly (P < 0.01) lower during prednisolone treatment. Despite the decreased tsh response incremental change in serum T4 concentration during oral treatment with prednisolone, the lowest value observed fell within the before-treatment range. In addition, during treatment, baseline serum T3 and T4 concentrations after tsh administration increased, on average, 3.7 and 8.4 times, respectively.

Free access
in American Journal of Veterinary Research

Abstract

Objective

To use indirect calorimetry to compare heat production between gonadectomized and sexually intact male and female cats.

Design

Male (n = 6) and female (n = 6) kittens were gonadectomized at 7 weeks or 7 months of age, or left sexually intact. Body heat production was measured by indirect calorimetry in all cats at 12, 18, and 24 months of age.

Animals

18 male and 18 female clinically normal domestic shorthair cats.

Procedure

Heat production was measured, using an open-circuit, respiratory, indirect calorimeter. All cats underwent calorimetry at 12, 18, and 24 months of age. The heat coefficient, a measure of resting metabolic rate, was calculated for each cat at each test; heat coefficient is defined as logarithm of heat (kcal/h) divided by logarithm of body weight (kg).

Results

Heat production did not vary with age in male or female cats. Heat coefficient was higher in sexually intact male and female cats than in gonadectomized male and female cats at 12, 18, and 24 months of age (12 months, females, P < 0.01, males, P = 0.04; 18 months, females, P < 0.01, males, P = 0.02; and 24 months, females and males, P < 0.01).

Conclusions

These data suggest that resting metabolic rate in cats decreases after gonadectomy.

Clinical Relevance

A decrease in metabolic rate is synonymous with a decrease in caloric requirements. Gonadectomized animals fed in a manner similar to sexually intact animals may be predisposed to obesity and its sequelae.(Am J Vet Res 1996;57:371-374)

Free access
in American Journal of Veterinary Research

Summary

For 16 dogs with testicular neoplasia (n = 19 tumors), ultrasonography was performed to determine whether a correlation exists between ultrasonographic features of testicular tumors and cell type. The echogenicity of the tumors varied depending on the size of the tumor and whether the tumor had focal or diffuse distribution within the testis. The ultrasonographic characteristics of Sertoli cell tumors were variable, with no predominant pattern. This variation may be related to tumor size, because 6 of 7 Sertoli cell tumors were > 5 cm in diameter. Focal seminomas and interstitial cell tumors < 3 cm in diameter had hypoechoic texture. Focal seminomas and interstitial cell tumors > 3 cm in diameter had mixed echogenicity. Tumors of multiple cell types were > 5 cm in diameter and had mixed echogenicity. In valuable breeding dogs with a small (< 3 cm) focal intrascrotal lesion, testicular ultrasonography would be of benefit for localization of the mass to the testis or epididymis for subsequent biopsy. In dogs with intra-abdominal neoplastic testes, ultrasonography may be of benefit in determining intra-abdominal metastases and invasion of contiguous structures.

Free access
in Journal of the American Veterinary Medical Association

Abstract

Objective—To determine the effect of the 5α-reductase inhibitor finasteride on prostatic diameter and volume, semen quality, and serum dihydrotestosterone (DHT) and testosterone concentrations in dogs with spontaneous benign prostatic hypertrophy (BPH).

Design—Double-blind placebo-controlled trial.

Animals—9 dogs with BPH.

Procedure—Five dogs were treated with finasteride for 16 weeks (0.1 to 0.5 mg/kg [0.05 to 0.23 mg/lb] of body weight, PO, q 24 h); the other 4 received a placebo. Prostatic diameter, measured radiographically, prostatic volume, measured ultrasonographically, semen quality, and serum DHT and testosterone concentrations were evaluated before and during treatment. After receiving the placebo for 16 weeks, the 4 control dogs were treated with finasteride for 16 weeks, and evaluations were repeated.

Results—Finasteride significantly decreased prostatic diameter (mean percentage decrease, 20%), prostatic volume (mean percentage decrease, 43%), and serum DHT concentration (mean percentage decrease, 58%). Finasteride decreased semen volume but did not adversely effect semen quality or serum testosterone concentration. No adverse effects were reported by owners of dogs in the study.

Conclusions and Clinical Relevance—Results suggest that finasteride can be used to reduce prostatic size in dogs with BPH without adversely affecting semen quality or serum testosterone concentration. (J Am Vet Med Assoc 2001;218:1275–1280)

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in Journal of the American Veterinary Medical Association