Steroid hormone concentration profiles in healthy intact and neutered dogs before and after cosyntropin administration

The purpose of this study was to determine steroid hormone concentration profiles in healthy intact and neutered male and female dogs. Seventeen intact female dogs, 20 intact male dogs, 30 spayed female dogs, and 30 castrated male dogs were used in this study. Serum samples were collected before and 1h after cosyntropin administration, and serum concentrations were determined for cortisol, progesterone, 17-OH progesterone (17-OHP), dehydroepiandrosterone sulfate (DHEAS), androstenedione, testosterone, and estradiol. Intact male dogs had greater concentrations of DHEAS, androstenedione, and testosterone. Intact female dogs had greater concentrations of progesterone. There was no significant difference in estradiol concentration among the four groups. Intact male dogs had lower concentrations of cortisol post-stimulation. DHEAS and testosterone did not increase in response to ACTH in intact males, and estradiol concentrations did not increase in response to ACTH in any group. Results from this study will enhance interpretation of suspected adrenal and/or gonadal disorders of dogs. Because estradiol concentrations were similar in all groups of dogs, measuring estradiol may not be a useful diagnostic test. Cortisol concentrations for intact male dogs with hyperadrenocorticism may be lower than those of female or neutered dogs.     

Investigation of the reproductive and growth hormone status of dogs affected by idiopathic recurrent flank alopecia

The reproductive and growth hormone status of a group of 12 neutered dogs affected by idiopathic recurrent flank alopecia was investigated at both maximum and minimum photoperiod using the adrenocorticotrophic hormone (ACTH) stimulation test, the xylazine stimulation test and the insulin-like growth factor I (IGF-I) assay. When compared with a group of nine neutered control dogs, the plasma reproductive hormone concentrations were not significantly different with one exception; a significantly greater post-ACTH plasma progesterone concentration was detected in the affected group at minimum photoperiod (P<0–05). The significance of this finding in isolation is unclear. Growth hormone response to intravenous xylazine was assessed in the affected group at maximum photoperiod only and was found to be within normal limits in eight of the dogs. Serum IGF-I concentrations were significantly greater in the affected group at maximum photoperiod but the groups were not significantly different at minimum photoperiod. These results suggest that dogs with idiopathic recurrent flank alopecia are of normal reproductive and growth hormone status.     

Steroidogenic response of adrenal tissues after administration of ACTH to dogs with hypercortisolemia

OBJECTIVE: To evaluate adrenal sex hormone concentrations in neutered dogs with hypercortisolemia. DESIGN: Case series. ANIMALS: 11 neutered dogs with hypercortisolemia. PROCEDURE: Serum samples obtained before and 1 hour after administration of ACTH were evaluated for concentrations of cortisol, progesterone, testosterone, dehydroepiandrosterone sulfate or androstenedione or both, and 17-hydroxyprogesterone. RESULTS: For all dogs, concentrations of 1 or more adrenal sex hormones were substantially greater than reference range values before or after administration of ACTH. Testosterone concentration was not greater than reference range values in any of the dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Results emphasize the importance of ruling out hypercortisolemia before measuring adrenal sex hormone concentrations as a means of diagnosing adrenal hyperplasia syndrome (alopecia X) in dogs.     

Prevalence of serum thyroid hormone autoantibodies in dogs with clinical signs of hypothyroidism

OBJECTIVE: To determine prevalence of thyroid hormone autoantibodies (THAA) in serum of dogs with clinical signs of hypothyroidism. DESIGN: Cohort study. SAMPLE POPULATION: 287,948 serum samples from dogs with clinical signs consistent with hypothyroidism. PROCEDURE: Serum THAA were detected by use of a radiometric assay. Correlation and chi2 analyses were used to determine whether prevalence varied with breed, age, sex, or body weight. Only breeds for which > or = 50 samples had been submitted were used for analysis of breed prevalence. RESULTS: Thyroid hormone autoantibodies were detected in 18,135 (6.3%) samples. The 10 breeds with the highest prevalence of THAA were the Pointer, English Setter, English Pointer, Skye Terrier, German Wirehaired Pointer, Old English Sheepdog, Boxer, Maltese, Kuvasz, and Petit Basset Griffon Vendeen. Prevalence was significantly correlated with body weight and was highest in dogs between 2 and 4 years old. Females were significantly more likely to have THAA than were males. CONCLUSIONS AND CLINICAL RELEVANCE: Thyroid hormone autoantibodies may falsely increase measured triiodothyronine (T3) and thyroxine (T4) concentrations in dogs; results suggest that T3 concentration may be falsely increased in approximately 57 of 1,000 dogs with hypothyroidism and that T4 concentration may be falsely increased in approximately 17 of 1,000 dogs with hypothyroidism. Results also suggested that dogs of certain breeds were significantly more or less likely to have THAA than were dogs in general.     

Secretion of sex hormones in dogs with adrenal dysfunction

OBJECTIVE: To evaluate adrenal sex hormone concentrations in response to ACTH stimulation in healthy dogs, dogs with adrenal tumors, and dogs with pituitary-dependent hyperadrenocorticism (PDH). DESIGN: Prospective study. ANIMALS: 11 healthy control dogs, 9 dogs with adrenal-dependent hyperadrenocorticism (adenocarcinoma [ACA] or other tumor); 11 dogs with PDH, and 6 dogs with noncortisol-secreting adrenal tumors (ATs). PROCEDURE: Hyperadrenocorticism was diagnosed on the basis of clinical signs; physical examination findings; and results of ACTH stimulation test, low-dose dexamethasone suppression test, or both. Dogs with noncortisol-secreting ATs did not have hyperadrenocorticism but had ultrasonographic evidence of an AT. Concentrations of cortisol, androstenedione, estradiol, progesterone, testosterone, and 17-hydroxyprogesterone were measured before and 1 hour after i.m. administration of 0.25 mg of synthetic ACTH. RESULTS: All dogs with ACA, 10 dogs with PDH, and 4 dogs with ATs had 1 or more sex hormone concentrations greater than the reference range after ACTH stimulation. The absolute difference for progesterone, 17-hydroxyprogesterone, and testosterone concentrations (value obtained after ACTH administration minus value obtained before ACTH administration) was significantly greater for dogs with ACA, compared with the other 3 groups. The absolute difference for androstenedione was significantly greater for dogs with ACA, compared with dogs with AT and healthy control dogs. CONCLUSIONS AND CLINICAL RELEVANCE: Dogs with ACA secrete increased concentrations of adrenal sex hormones, compared with dogs with PDH, noncortisol-secreting ATs, and healthy dogs. Dogs with noncortisol-secreting ATs also have increased concentrations of sex hormones. There is great interdog variability in sex hormone concentrations in dogs with ACA after stimulation with ACTH.     

The effects of thyroid hormones on the skin of beagle dogs

The effects of hypothyroidism on canine skin were determined by comparing morphologic, morphometric, and hair cycle differences in skin biopsy samples from 3 groups of age- and gender-matched Beagle dogs: (1) euthyroid dogs; (2) dogs made hypothyroid by administration of 131I; and (3) dogs made hypothyroid and maintained in a euthyroid state by treatment with synthetic thyroxine. After 10 months of observation, there was slower regrowth of hair 2 months after clipping in the untreated-hypothyroid dogs. Untreated-hypothyroid dogs had a greater number of follicles in telogen and fewer hair shafts (ie, a greater number of hairless telogen follicles) than did the control group. The control dogs had a greater number of telogen follicles but the same number of hair shafts as the treated-hypothyroid group. Treated-hypothyroid dogs had the greatest number of follicles in the growing stage of the hair cycle (anagen). This study suggests that, at least in Beagles, induced hypothyroidism does not affect the pelage as dramatically as has been described in naturally occurring disease. This is because normal Beagles retain hair shafts in follicles for long periods, and the alopecia of hypothyroidism appears to evolve slowly because of the prolongation of this haired telogen stage. The evaluation of thyroxine-treated hypothyroid dogs demonstrates that thyroid hormone supplementation of Beagle dogs with induced hypothyroidism stimulates hair growth.     

Canine hyperadrenocorticism: pretreatment clinical and laboratory evaluation of 117 cases.

The physical findings, clinical signs, age, breed and sex distributions, and laboratory data of 117 dogs with untreated Cushing's syndrome were reviewed. Poodles, Dachshunds, and Boxers of all ages were found to be at increased risk, as were dogs of all breeds greater than or equal to 6 years old. Polydipsia, polyuria, progressive bilaterally symmetric alopecia, and abdominal distention were the most frequently observed clinical signs and physical findings. Lymphopenia, eosinopenia, above normal values of serum alkaline phosphatase, serum cholesterol, and sulfobromphthalein dye retention, and below normal urine specific gravity were the most frequent abnormalities found in the laboratory data. About 50% of the dogs had urinary tract infections. Final diagnosis was established on the basis of abnormally high plasma corticosteroid values in response to an intramuscular injection of adrenocorticotropic hormone.     

FC-12 Diagnostic value of skin biopsy in feline symmetric alopecia

Hair loss in Chesapeake Bay retrievers has been increasingly recognized by breeders in recent years. Anecdotal reports suggest an endocrine disorder or follicular dysplasia as the underlying cause, but no scientific study has been done to investigate the underlying problem. A prospective study was carried out in collaboration with the American Chesapeake Club. Affected dogs were recruited into the study. Routine dermatological and hormonal (blood and urine) tests, and skin biopsies were performed. Ten dogs (age 1.5–10 years), seven females (two spayed) and three males (two neutered), were included in the study. All dogs had mild or severe hair loss affecting the lateral ventral chest, flanks, rump and thighs. Affected dogs were clinically healthy. Hormonal tests revealed normal thyroid hormone panels, insulin-like growth factor-1 levels, and urinary cortisol:creatinine ratios in samples collected for ten consecutive days. In six of 10 dogs, an adrenal hormone panel showed slight or moderate increased values pre- and/or post-ACTH stimulation of cortisol (three of six), 17-hydroxyprogesterone (five of six), androstenedione (three of six), estradiol (two of six) and progesterone (six of six). The major histopathologic changes resembled canine flank alopecia and follicular dysplasia with pronounced infundibular hyperkeratosis, mild follicular atrophy, and occasional melanin clumping with dystrophic hair shafts. Chesapeake Bay retrievers suffer from a type of hair loss that is likely related to an abnormal production of adrenal sex hormone. Further studies are currently underway to determine if there is a heritable basis for this disease and to evaluate therapeutic options.
Funding: University of Pennsylvania.     

Plasma steroid hormone concentrations and their relationships in Suffolk ewes during gestation and parturition

In this study, we measured plasma concentrations of progesterone, pregnenolone, estradiol, estrone, estrone sulfate, and cortisol and analyzed the correlations between these hormones during gestation in 13 Suffolk ewes, the main breed in Japan. Progesterone increased during gestation and decreased a few days before parturition; however, this pattern was different in samples with high progesterone concentrations (P4 spike samples). This P4 spike was associated with a high pregnenolone concentration. Apart from the P4 spike, the progesterone change was similar to that in other sheep breeds. Pregnenolone increased during gestation and decreased after parturition. A significant correlation between progesterone and pregnenolone was observed a few days before parturition. Estrone sulfate and estradiol concentrations increased during gestation, but estrone did not. They increased shortly before parturition, and then decreased immediately after parturition. At parturition, the correlation between estrone and estrone sulfate was significantly stronger. Moreover, a strong correlation between estrone sulfate and estradiol was observed after parturition. Cortisol did not change during gestation and increased shortly before parturition. The results showed steroid hormone dynamics in normal pregnant Suffolk ewes, which were mostly in line with those of other sheep breeds. It should be noted that high progesterone concentrations altered the typical patterns.     

Adrenal steroid hormone concentrations in dogs with hair cycle arrest (Alopecia X) before and during treatment with melatonin and mitotane

The purpose of the study was to evaluate intermediate adrenal steroid hormones (ISH) in neutered dogs with hair cycle arrest (Alopecia X) during treatment with melatonin, and to see if hair re-growth is associated with sex hormone concentrations within the normal ranges. Twenty-nine neutered, euthyroid, and normo-cortisolemic dogs were enrolled in the study (23 Pomeranians, three keeshonds, two miniature poodles, and one Siberian husky). Coat assessment and an ACTH stimulation test were performed pre-treatment and approximately every 4 months for a year post treatment. Melatonin was administered initially at 3-6 mg, every 12 h. Based on clinical progression, each dog was continued on the current dose of melatonin, given an increased dose of melatonin or changed to mitotane. Partial to complete hair re-growth occurred in 14/23 Pomeranians, and partial re-growth in 3/3 keeshond and 1/2 poodle dogs. A Siberian husky dog failed to re-grow hair. Fifteen dogs had partial hair re-growth at the first re-evaluation. Melatonin dosage was increased in eight dogs but only one had improved hair re-growth. On mitotane treatment, partial to complete hair re-growth was seen in 4/6 dogs and no re-growth in 2/6 dogs. No significant decrease in sex hormone concentrations were seen during melatonin or mitotane treatment. Concentrations of ISH in dogs with hair re-growth did not differ significantly from pre-treatment values. At the completion of the study, androstenedione, progesterone and 17-hydroxyprogesterone were still above reference ranges in 21, 64 and 36%, respectively, of dogs with partial to complete hair re-growth. In conclusion, 62% of dogs had partial to complete hair re-growth. However, not all dogs with hair re-growth had concentrations of ISH within the normal range.     

Immunohistochemical study of hormonal receptors and cell proliferation in normal canine mammary glands and spontaneous mammary tumours

The expression of hormone receptors and their relationship to cell proliferation in six samples of normal canine mammary tissue, and 11 benign and 10 malignant mammary neoplasms from female dogs were assessed by immunohistochemistry in formalin-fixed paraffin-embedded samples, by using monoclonal antibodies against progesterone and oestrogen receptors, and nuclear antigen Ki-67 (MIB-1). Malignant tumours negative for progesterone receptors proliferated at higher rates than progesterone receptor-positive tumours, suggesting that the progression towards malignancy in spontaneous mammary tumours is accompanied by a decrease in hormonal steroid dependency. Only one malignant tumour was positive for oestrogen receptors.     

Use of breed-specific ranges for the vertebral heart scale as an aid to the radiographic diagnosis of cardiac disease in dogs.

The vertebral heart scale was measured on right lateral recumbent thoracic radiographs of 320 dogs of six popular breeds, including for each breed at least 20 dogs with no clinical signs of cardiovascular or respiratory disease and at least 19 dogs with cardiac or respiratory disease. There were significant differences between the mean values of the scale for the different breeds; the normal boxer dogs had a significantly higher mean value than the normal dogs of all the other breeds, and the labrador retrievers had a significantly higher mean value than all the other breeds except the boxer and the cavalier King Charles spaniel. For all the breeds except the boxer, there was a trend for dogs with cardiac disease (but not respiratory disease) to have higher mean values on the scale than normal dogs of the same breed; however, at the optimal value of the scale for distinguishing between dogs of each breed with and without cardiac disease, the sensitivity and specificity were relatively low, in the range 58 to 83 per cent. The scale was most accurate for the diagnosis of cardiac disease in the Yorkshire terrier and the cavalier King Charles spaniel, breeds affected by predominantly dilative forms of cardiac disease. In contrast, it was very inaccurate in the boxer, a breed that has a higher incidence of cardiac diseases associated with concentric hypertrophy.     

FC‐10 Adult‐onset hair loss in Chesapeake Bay retrievers: a clinical and histological study

Hair loss in Chesapeake Bay retrievers has been increasingly recognized by breeders in recent years. Anecdotal reports suggest an endocrine disorder or follicular dysplasia as the underlying cause, but no scientific study has been done to investigate the underlying problem. A prospective study was carried out in collaboration with the American Chesapeake Club. Affected dogs were recruited into the study. Routine dermatological and hormonal (blood and urine) tests, and skin biopsies were performed. Ten dogs (age 1.5–10 years), seven females (two spayed) and three males (two neutered), were included in the study. All dogs had mild or severe hair loss affecting the lateral ventral chest, flanks, rump and thighs. Affected dogs were clinically healthy. Hormonal tests revealed normal thyroid hormone panels, insulin‐like growth factor‐1 levels, and urinary cortisol:creatinine ratios in samples collected for ten consecutive days. In six of 10 dogs, an adrenal hormone panel showed slight or moderate increased values pre‐ and/or post‐ACTH stimulation of cortisol (three of six), 17‐hydroxyprogesterone (five of six), androstenedione (three of six), estradiol (two of six) and progesterone (six of six). The major histopathologic changes resembled canine flank alopecia and follicular dysplasia with pronounced infundibular hyperkeratosis, mild follicular atrophy, and occasional melanin clumping with dystrophic hair shafts. Chesapeake Bay retrievers suffer from a type of hair loss that is likely related to an abnormal production of adrenal sex hormone. Further studies are currently underway to determine if there is a heritable basis for this disease and to evaluate therapeutic options. Funding: University of Pennsylvania.     

Effects of oestradiol-17beta and testosterone on progesterone production in the cultured granulosa cells of Japanese quail

In order to study the effects of steroid hormones on steroidogenesis in the avian ovary, quail granulosa cells were cultured with follicle stimulating hormone (FSH), oestradiol-17beta or testosterone. The progesterone content of the medium during the culture period of 66 h and the following 3 h of incubation with luteinising hormone (LH), was measured by radioimmunoassay. When FSH, oestradiol-17beta or testosterone were added during the 66 h culture, subsequent progesterone production by the cells during 3 h of incubation with LH was significantly increased. However, testosterone also stimulated progesterone production in the medium during the 66 h culture period, whereas FSH oroestradiol-17beta did not. Addition of staurosporine during culture inhibited both LH-stimulated progesterone production and testosterone-stimulated progesterone production. These results indicate that the processes during which granulosa cells acquired responsiveness to LH, and testosterone stimulates progesterone production might both be mediated by a staurosporine-sensitive protein kinase C-dependent pathway in quail granulosa cells.     

Effect of oral melatonin administration on sex hormone, prolactin, and thyroid hormone concentrations in adult dogs.

OBJECTIVE: To determine the effect of oral melatonin (MT) administration on serum concentrations of sex hormones, prolactin, and thyroxine in dogs. DESIGN: Prospective study. ANIMALS: 8 male and 8 female adult sexually intact dogs. PROCEDURE: 5 male and 5 female dogs were treated with MT (1.0 to 1.3 mg/kg [0.45 to 0.59 mg/lb] of body weight), PO, every 12 hours for 28 days; the other 6 dogs were used as controls. Blood samples were collected on days 0, 14, and 28, and serum concentrations of estradiol-17 beta, progesterone, testosterone, androstenedione, 17-hydroxyprogesterone (17-HP), dihydroepiandrostenedione sulfate (DHEAS), prolactin, and thyroxine were determined. On day 5, serum MT concentrations were measured before and periodically for up to 8 hours after MT administration in 4 treated dogs. RESULTS: Female dogs treated with MT had significant decreases in serum estradiol, testosterone, and DHEAS concentrations between days 0 and 28. Male dogs treated with MT had significant decreases in serum estradiol and 17-HP concentrations between days 0 and 28. Serum MT concentrations increased significantly after MT administration and remained high for at least 8 hours. Prolactin and thyroxine concentrations were unaffected by treatment. CONCLUSIONS AND CLINICAL RELEVANCE: Melatonin is well absorbed following oral administration and may alter serum sex hormone concentrations.     

Survey with follow-up of 67 dogs with testicular sertoli cell tumours

Sixty-seven cases of canine sertoli cell tumour are reviewed. The mean age at diagnosis was 9.5 years (sd +/- 2.1, range 3 to 17). The most commonly affected breeds were boxer, cairn terrier, labrador retriever, border collie, German shepherd and rough collie. The left side was affected in 28 dogs (42 per cent), the right in 35 (52.5 per cent) and both sides in four (6 per cent). Twenty testicles were abdominal (left, seven; right, 13), seven were inguinal (left, four; right, three) and 44 were scrotal (left, 21; right, 23). Hormonal signs were evident in 38 (57 per cent) animals (feminisation with alopecia in 21, symmetrical alopecia alone in 17). Other types of testicular tumours were found in 12 dogs (18 per cent) of this series. Of 42 dogs which were castrated and discharged, 38 were available for follow-up study and survived for between one week and five years. Two of the 15 dogs which were subject to post mortem examination had metastases. Two others which died after failure of remission, or a recurrence of the hormonal changes probably also had metastases. Two of the 25 dogs which were presented initially for other reasons, but had sertoli cell tumours, were found to have metastases post mortem. The boxer, cairn terrier, border collie, Shetland collie and pekingese had a higher risk of sertoli cell tumour than other breeds.     

Prevalence of the breed-related glaucomas in pure-bred dogs in North America

Objective To determine the prevalence of the breed‐related glaucomas in pure‐bred dogs presented to the veterinary medical teaching hospitals in North America that participate in the Veterinary Medical Data Base (VMDB). Materials and methods In this retrospective study, age of first diagnosis, breed, and gender data for all breeds of dogs were collected from the VMDB with the clinical diagnosis of primary glaucoma (glaucoma‐NOS) at 5–10 year intervals from 1964 to 2002. The prevalence for each breed (affected dogs compared to all dogs of each breed), any changes over the 38 years, and any gender differences for these glaucomas were determined. Results The prevalence of the primary breed‐related glaucomas has gradually increased from 0.29% (1964–1973); 0.46% (1974–1983); 0.76% (1984–1993); to 0.89% (1994–2002). Breeds that consistently featured among the highest 10 for glaucoma prevalence from four different periods (1964 to 2002) included American Cocker Spaniel, Basset Hound, Wire Fox Terrier, and Boston Terrier. During the last observation period (1994–2002), 22 different breeds had 1% or higher prevalence of the glaucomas. The highest prevalence of glaucomas in 1994–2002 by breed included: American Cocker Spaniel (5.52%); Basset Hound (5.44%); Chow Chow (4.70%); Shar‐Pei (4.40%); Boston Terrier (2.88%); Wire Fox Terrier (2.28%); Norwegian ElkHound (1.98%); Siberian Husky (1.88%); Cairn Terrier (1.82%); and Miniature Poodle (1.68%). A predominance of females with glaucoma occurred in the American Cocker Spaniel, Basset Hound, Cairn Terrier, Chow Chow, English Cocker Spaniel, Samoyed, and perhaps the Siberian Husky, and a predominance of males in the Australian Cattle dog and St Bernard. Age affected the time for first presentation of the glaucomas in the pure‐bred dog. In the majority of breeds the glaucomas were presented for initial diagnosis in dogs between 4 and 10 years of age. Conclusion Breed‐related glaucomas in pure‐bred dogs are frequently presented to the veterinary medical teaching hospitals in North America. The prevalence of the breed‐related glaucomas in the dog appears similar to humans, and in some breeds exceeds that in humans. In many breeds the high prevalence of the glaucomas suggests a genetic basis.     

Comparison of two radiographic techniques for evaluation of hip joint laxity in 10 breeds of dogs

OBJECTIVE: To evaluate hip joint laxity in 10 breeds of dogs via 2 radiographic techniques. ANIMALS: 500 clinically normal dogs. DESIGN: Prospective study. PROCEDURE: Radiographs obtained via routine hip joint evaluations performed in sedated dogs of 10 popular breeds were randomly selected from a database. Measurements of distraction index (DI) and hip-extended index (HEI) on 1 hip joint radiograph randomly chosen from each dog were made. RESULTS: Mean age of dogs was 20.7 months. Mean HEI was 0.17 (range, 0.0 to 0.72) and mean DI was 0.44 (range, 0.07 to 0.96). Borzois had uniformly tight hip joints as judged by use of both methods and were considered the gold standard by which hip joint laxity was judged (all Borzois had DI < or = 0.32). Overall, DI was significantly greater than HEI. Within each breed, mean DI was always greater than mean HEI. Significant differences were detected among breeds for HEI; however, compared with DI, the magnitude of differences among breeds was less. CONCLUSIONS AND CLINICAL RELEVANCE: Distraction radiography detected the greatest range and magnitude of passive hip laxity in the 10 breeds of dogs. The difference in values between breeds known to have high prevalence of canine hip dysplasia and those in Borzois was greater for DI than for HEI. Breeds must be evaluated individually because of inherent differences in hip joint laxity.     

Long-term study of aerobic bacteria of the genital tract in stud dogs.

The aerobic bacterial flora of the genital tract was characterized in 15 stud dogs in an 18-month study. The dogs represented 4 breeds and were from 3 kennels. Bacterial samples from the prepuce and semen were collected every month, except in connection with matings, when they were collected weekly (464 samples). The dogs that were included all mated at least once during the study. The mean pregnancy rate, litter size, and pup mortality for the bitches with which they had mated were all within normal limits. The most frequent bacteria isolated from the prepuce and semen were Pasteurella multocida, beta-hemolytic streptococci, and Escherichia coli. There was a tendency for breeds to differ in frequency of the most common bacterial species. Bacterial culture yielded no aerobic growth in 14.2% of the preputial samples and 69.8% of the semen samples. Bacteria were transferred between dog and bitch at mating. In this study of healthy breeding dogs, neither the fertility of the dog nor that of the bitch was affected by the bacteria transferred.     

Serum concentrations of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates in healthy dogs following stimulation with two doses of cosyntropin

OBJECTIVE: To compare the effects of 2 doses of cosyntropin (5 microg/kg vs 250 microg, IV) on serum concentrations of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates and determine the optimal sample collection time after adrenal stimulation with cosyntropin. ANIMALS: 10 healthy, privately owned, neutered dogs. PROCEDURE:Dogs were randomly assigned to initially receive cosyntropin at 5 microg/kg or as a total dose of 250 microg, IV. Dogs received the alternate dose 1 to 2 weeks later. Serum was obtained from blood samples collected before (0 minutes) and 30, 60, 90, and 120 minutes after cosyntropin administration. RESULTS:Maximum stimulation of cortisol, androstenedione, progesterone, and 17-hydroxyprogesterone production was achieved at 60 minutes following IV administration of cosyntropin at 5 microg/kg or as a total dose of 250 microg. Serum estradiol concentration did not increase in response to either cosyntropin dose. For all hormones, no significant difference in serum hormone concentrations was found among sample collection times of 0, 30, 60, and 90 minutes when comparing the 2 doses of cosyntropin. CONCLUSIONS AND CLINICAL RELEVANCE: Cosyntropin, when administered at 5 microg/kg, IV, effectively stimulated maximum production of cortisol, sex hormones of adrenal origin, and adrenocortical steroid intermediates at 1 hour after administration.