The Effects of Aging on Hematology and Serum Chemistry Values in the Beagle Dog

Lowseth, Lisa A.; Gillett, Nancy A.; Gerlach, Robert F.; Muggenburg, Bruce A.

doi:10.1111/j.1939-165x.1990.tb00535.x

Cited by 62 publications

(69 citation statements)

References 4 publications

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“…This is a new finding, as in most published studies only beagle dogs were used (James & Heywood 1979, Lowseth et al 1990 or differences in body and thus testes size were ignored (Taha & Noakes 1982). Our finding is in accordance with those of a study in which no relation was found between the size of the animal and testosterone concentrations in 10 different species (Wichmann et al 1984).…”

Section: Discussionsupporting

confidence: 82%

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Ageing, testicular tumours and the pituitary-testis axis in dogs

Peters

Jong²,

Teerds³

et al. 2000

Journal of Endocrinology

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Dogs of different ages without testicular diseases were evaluated to study possible age-related changes in hormone concentrations in serum. Dogs with testicular tumours were also investigated to study the relation between tumour type and hormone concentrations; in this study, dogs with Sertoli cell tumours, Leydig cell tumours and seminomas were included. We measured testosterone, oestradiol, LH, FSH and inhibin-like immunoreactivity concentrations in peripheral venous and testicular venous blood of these animals.In normal dogs there appeared to be no age-related changes in the concentrations of the investigated hormones, except for a significant age-related decrease in oestradiol concentrations in testicular venous blood (P<0·02). Dogs with a Sertoli cell tumour had greater oestradiol concentrations and inhibin-like immunoreactivity in both peripheral and testicular venous blood than did dogs without a neoplasm (P<0·05). Testosterone concentrations were reduced in dogs with Sertoli cell tumours, as were FSH and LH. Feminisation occurred in eight of 13 dogs with a Sertoli cell tumour and in two of 14 dogs with a Leydig cell tumour; it was accompanied by a significantly greater oestradiol concentration than in normal dogs and in dogs with Sertoli cell tumours without signs of feminisation. Dogs with a Leydig cell tumour had greater concentrations of oestradiol and inhibin-like immunoreactivity in both peripheral venous and testicular venous blood than did dogs without a neoplasm (P<0·05). The testosterone concentration in testicular venous blood of these dogs was lower than that in dogs with normal testes. The concentration of LH in peripheral venous blood was also reduced (P<0·05). Hormone concentrations in dogs with a seminoma were not different from those in normal dogs.It was concluded that seminomas are not endocrinologically active. In contrast, both Sertoli cell tumours and Leydig cell tumours can cause increased oestrogen production leading to signs of feminisation. These tumours also have considerable amounts of inhibin-like immunoreactivity, but only in Sertoli cell tumours does this result in a reduction in FSH concentrations, suggesting that Sertoli cell tumours secrete dimeric inhibin, whereas Leydig cell tumours presumably produce loose -subunits that cross-react in the inhibin assay but are not biologically active.

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Section: Discussionsupporting

confidence: 82%

“…Either no reduction with age (Taha & Noakes 1982, Lowseth et al 1990 or decreasing testosterone concentrations has been reported (Bondarenko et al 1979, Günzel Apel et al 1990; in accordance with the latter observation, lower LH concentrations were observed in aged dogs also (Günzel Apel et al 1990).…”

Section: Introductionsupporting

confidence: 72%

Ageing, testicular tumours and the pituitary-testis axis in dogs

Peters

Jong²,

Teerds³

et al. 2000

Journal of Endocrinology

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“…But also, there is a suggestion that brain pathology, including the age of onset and extent may vary across breeds (Bobik et al 1994). In laboratory beagles, the median lifespan (i.e., 50% have died) can be as high as 12-14 years depending on the colony evaluated (Lowseth et al 1990;Albert et al 1994). Of note, there are examples of "exceptional longevity" in pet/companion dogs (Cooley et al 2003) consistent with increasing numbers of "oldest-old" human in our aging population (Head et al 2007).…”

Section: Introductionmentioning

confidence: 96%

Neurobiology of the aging dog

Head

2010

AGE

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Aged canines naturally accumulate several types of neuropathology that may have links to cognitive decline. On a gross level, significant cortical atrophy occurs with age along with an increase in ventricular volume based on magnetic resonance imaging studies. Microscopically, there is evidence of select neuron loss and reduced neurogenesis in the hippocampus of aged dogs, an area critical for intact learning and memory. The cause of neuronal loss and dysfunction may be related to the progressive accumulation of toxic proteins, oxidative damage, cerebrovascular pathology, and changes in gene expression. For example, aged dogs naturally accumulate human-type beta-amyloid peptide, a protein critically involved with the development of Alzheimer's disease in humans. Further, oxidative damage to proteins, DNA/RNA and lipids occurs with age in dogs. Although less well explored in the aged canine brain, neuron loss, and cerebrovascular pathology observed with age are similar to human brain aging and may also be linked to cognitive decline. Interestingly, the prefrontal cortex appears to be particularly vulnerable early in the aging process in dogs and this may be reflected in dysfunction in specific cognitive domains with age.

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“…Urea was increased in 14-year-old dogs. 43 Last, a lifetime study of laboratory Beagles from the Center for Environmental Toxicology and Technology at Colorado State University reported autopsy findings for 276 control dogs, 95% of which were >10 years of age. In this cohort, chronic azotemic renal disease was the cause of death in 22 control dogs (8%).…”

Section: Clinicopathologic Changes In Aged Dogsmentioning

confidence: 99%

Aging in the Canine Kidney

2015

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Given the irreversible nature of nephron loss, aging of the kidney is of special interest to diagnostic and toxicologic pathologists. There are many similarities among histologic lesions in aged human and canine kidneys, including increased frequency of glomerulosclerosis, interstitial fibrosis, and tubular atrophy. Unfortunately, there are few studies in which renal tissue from aged healthy dogs was adequately examined with advanced diagnostics-namely, transmission electron microscopy and immunofluorescence-so age-associated changes in canine podocytes and glomerular basement membranes are poorly characterized. An age-associated decrease in the glomerular filtration rate in humans and dogs (specifically small breed dogs) has been documented. Although lesions in aged rats and mice differ somewhat from those of aged dogs and humans, the knowledge gained from rodent models is still vital to elucidating the pathogenesis of age-associated renal disease. Many novel molecules implicated in renal aging have been identified through genetically modified rodent models and transcriptomic and proteomic analysis of human kidneys. These molecules represent intriguing therapeutic targets and diagnostic biomarkers. Likewise, influencing critical pathways of cellular aging, such as telomere shortening, cellular senescence, and autophagy, could improve renal function in the elderly.

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The Effects of Aging on Hematology and Serum Chemistry Values in the Beagle Dog

Cited by 62 publications

References 4 publications

Ageing, testicular tumours and the pituitary-testis axis in dogs

Ageing, testicular tumours and the pituitary-testis axis in dogs

Neurobiology of the aging dog

Aging in the Canine Kidney

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