Fluctuations in Peripheral Serum Testosterone Levels within a Day, with Age and by Sexual Stimulation in Male Beagle Dogs Bred Indoors

Fukuda, Satoshi; Nagashima, Hiroshi; Morioka, Kazunori; Aoki, Junji

doi:10.1538/expanim1978.37.4_381

Cited by 6 publications

(19 citation statements)

References 8 publications

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“…All histomorphometric values, e.g., bone volume and bone formation rate, showed adult states after at least 12 months old [5]. We also reported in a previous study that serum testosterone levels in male beagle dogs remained high with a regular circadian rhythm from 6 months to 12 years, and that the levels increased further from 13 to 16 years [6]. This indicates that osteoporosis due to the alterations of sex hormones and functions, such as those that occur with age, do not occur spontaneously in male dogs.…”

Section: Animalssupporting

confidence: 82%

“…Although our findings have demonstrated that the loss of sex hormones produced by orchidectomy in male dogs successfully changed both the serum biochemical and histomorphometric parameters, which suggests the occurrence of osteoporosis, the histomorphometric and serum biochemical parameters did not always change in ovariectomized dogs [14,18]. Such sex differences may be due to the maintenance of high levels of sex hormones such as testosterone in male dogs [6], while in female dogs, the intervals in the estrus cycle are long (220 ± 56 days) and the increases in sex hormones during estrus occur for a short time (only 7-14 days) [1]. Alternatively, there may be differences in the effects of male and female sex hormones on bone metabolism.…”

Section: Discussioncontrasting

confidence: 62%

“…These parameters were checked, incompletely, for cross reactivities between dogs and humans, and with each other. Finally the testosterone concentration was also determined by radioimmunoassay (Eiken Co.) [6].…”

Section: Animalsmentioning

confidence: 99%

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Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Fukuda¹,

Iida²

2000

The Journal of Veterinary Medical Science

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ABSTRACT. The effects of orchidectomy on bone metabolism in male beagle dogs were examined using twelve 2-year-old dogs that were orchidectomized. The dogs' bilateral iliac bones, double-labeled with tetracycline and calcein for the histomorphometry, were obtained from three dogs prior to orchidectomy and at 3, 6, 9, and 12 months afterwards. The serum biochemical constituents related to bone metabolism were examined before and every month after orchidectomy. Between 1 and 6 months after orchidectomy, the value of serum testosterone decreased (1 month), while the levels of parathyroid hormone, calcitonin, total calcium, osteocalcin, and alkaline phosphatase activity increased significantly, indicating a high bone turnover. The mean trabecular thickness and the fraction of labeled osteoid surface decreased significantly 3 months after orchidectomy, but other histomorphometric parameters were unchanged. In the period 7-12 months after orchidectomy, the parathyroid hormone level increased ever and above that of the first 6-month period, while the levels of calcitonin, osteocalcin, alkaline phosphatase activity, and phosphorus decreased. The bone volume, mean trabecular thickness, and the fraction of labeled trabecular surface decreased significantly compared with the pre-orchidectomy values. These findings indicate an imbalance in bone metabolism ( i.e. bone resorption > bone formation). These results indicate that a loss of bone volume accompanied the fall in sex hormone levels following orchidectomy and suggest that the orchidectomized dog is available as an animal model for studying osteoporosis caused by hypogonadism and the decline of sex functions in men.-KEY WORDS: bone histomorphometry, canine, iliac bone, orchidectomy.

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Section: Animalssupporting

confidence: 82%

Section: Discussioncontrasting

confidence: 62%

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Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Fukuda¹,

Iida²

2000

The Journal of Veterinary Medical Science

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“…2) It was distinctly recognized that the circadian rhythm in T level which we reported previously [3] was unchanged by the reversal of the lighting time zone for 54 weeks in this study. This result indicates that the cyclic pattern of hormone release is due to some inherent central rhythm [4].…”

Section: Resultssupporting

confidence: 66%

“…We reported that the serum testosterone (T) level in male beagle dogs fluctuated according to a circadian rhythm [3].…”

mentioning

confidence: 99%

Circadian Rhythm of Serum Testosterone Levels in Male Beagle Dogs—Effects of Lighting Time Zone—

Fukuda¹

1990

Experimental Animals

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Effects of LHRH‐analogue treatment of spermatogenic dysfunction in the dog

et al. 1991

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Three male dogs, aged 2-4 years, which exhibited a high percentage of sperm with abnormal tails in their semen and low levels of peripheral plasma LH and testosterone were given two injections of 400 micrograms an LHRH analogue (LHRH-A) 3 h apart. The semen quality of all three dogs and the peripheral plasma levels of LH and testosterone were examined in two of the dogs. Plasma levels of LH and testosterone in both dogs peaked at 30 and 90 min respectively, after the injection of LHRH-A. The semen quality of all three dogs had improved temporarily 20 days after the injection. To be specific, although the mean percentage of sperm with abnormal tails in the three dogs was 19, 26 and 32% respectively before injection of LHRH-A, these values had decreased to 10, 16 and 13%, respectively, 20-40 days later. Thereafter, however, the percentage sperm abnormalities increased again. The testes and epididymides of two of the dogs were examined histologically at the end of 90 days. Sloughed germ cells were observed in the seminiferous tubules of the testes, and pyknotic epithelial cells were noted in some of the epididymal ducts. The other dog, which had a history of three unsuccessful matings was treated again with LHRH-A and mated with three bitches 30, 75, and 110 days later, respectively. Only the bitch mated with this dog 30 days after a second series of injections conceived. It is assumed that the semen quality of the three dogs improved because of a temporary rise in plasma LH and testosterone levels after the injection of LHRH-A. It is concluded that the fertility of dogs with a high percentage of sperm with abnormal tails can be improved approximately 30 days after treatment with an LHRH-A.

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Fluctuations in Peripheral Serum Testosterone Levels within a Day, with Age and by Sexual Stimulation in Male Beagle Dogs Bred Indoors

Cited by 6 publications

References 8 publications

Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Circadian Rhythm of Serum Testosterone Levels in Male Beagle Dogs—Effects of Lighting Time Zone—

Effects of LHRH‐analogue treatment of spermatogenic dysfunction in the dog

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Fluctuations in Peripheral Serum Testosterone Levels within a Day, with Age and by Sexual Stimulation in Male Beagle Dogs Bred Indoors

Cited by 6 publications

References 8 publications

Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Effects of Orchidectomy on Bone Metabolism in Beagle Dogs.

Circadian Rhythm of Serum Testosterone Levels in Male Beagle Dogs&mdash;Effects of Lighting Time Zone&mdash;

Effects of LHRH‐analogue treatment of spermatogenic dysfunction in the dog

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Circadian Rhythm of Serum Testosterone Levels in Male Beagle Dogs—Effects of Lighting Time Zone—