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PubMed1997

Effect of chronic food restriction on pulsatile luteinizing hormone secretion and hypothalamic neuropeptide Y gene expression in castrate male sheep.

Castrate male sheep (wethers, average liveweight 38 +/- 0.6 kg) were given one of the following diets for 10 weeks followed by euthanasia (n = 8/group): high-energy high-protein providing 1-5 times the energy required to maintain liveweight (maintenance) (group 1.5 M), low-energy low-protein at 0.5 maintenance (0.5 M), or low-energy high-protein at 0.5 maintenance (0.5 M + P). 1.5 M wethers gained 22% liveweight whereas 0.5 M and 0.5 M + P wethers lost 18 and 13% liveweight respectively. Relative to the 1.5 M group, the 0.5 M and 0.5 M + P groups had similar plasma concentrations of glucose and cortisol throughout, but elevated non-esterified fatty acids (P < 0.001) and reduced IGF-I and insulin (P < 0.05, 0.01 or 0.001) from 1 week onwards. Each week blood samples were taken every 12 min for 4 h and plasma assayed for LH. Mean concentration over 4 h, LH pulse frequency and LH pulse amplitude showed no progressive change in 1.5 M sheep. However, in both 0.5 M and 0.5 M + P groups mean LH increased (P < 0.001 and P < 0.01 respectively), pulse frequency decreased (P < 0.01 and P < 0.01) and pulse amplitude increased (P < 0.001 and P < 0.01) over the 10-week period. Anterior pituitary. LH content was greater in 0.5 M (P < 0.01) and 0.5 M + P (P < 0.05) than in 1.5 M sheep. Coronal sections (20 microns) of hypothalamic brain tissue were subjected to in situ hybridisation to determine gene expression for neuropeptide Y (NPY). NPY mRNA was concentrated in the arcuate nucleus and median eminence, with total amounts greater in both 0.5 M (310%, P < 0.001) and 0.5 M + P (333%, P < 0.01) groups than in 1.5 M sheep (100%). These data reveal that chronic low dietary energy intake by long-term castrates, with high or low protein intake, reduces LH pulse frequency but increases the circulating levels of LH by virtue of an increase in pulse amplitude, and concomitantly increases hypothalamic NPY gene expression.

Animals↗
PubMed2001

Progesterone and testosterone in combination act in the hypothalamus of castrated rams to regulate the secretion of LH.

We tested the hypotheses that progesterone enhances the negative feedback actions of testosterone in rams and that this occurs through actions at the hypothalamus. In the first part of this study, blood samples were collected every 10 min for 12 h before and after 7 days of treatment (i.m.) of castrated Romney Marsh rams (n=5 per group) with vehicle, progesterone (4 mg/12 h), testosterone (4 mg/12 h) or a combination of progesterone (4 mg/12 h) and testosterone (4 mg/12 h). In the second part of this study the brains of four gonad-intact Romney Marsh rams were collected, the hypothalamus was sectioned and in situ hybridisation of mRNA for progesterone receptors conducted. After 7 days of treatment with vehicle or progesterone or testosterone alone, there were no changes in the secretion of LH. In contrast, treatment with a combination of progesterone and testosterone resulted in a significant (P<0.01, repeated measures ANOVA) decrease in mean plasma concentrations of LH, the number of LH pulses per hour and the pre-LH pulse nadir and a significant (P<0.01) increase in the inter-LH pulse interval. We found cells containing mRNA for progesterone receptors throughout the hypothalamus, including the preoptic area (where most GnRH neurons are located in sheep), the periventricular, ventromedial and arcuate nuclei and the bed nucleus of the stria terminalis. This study shows that progesterone is capable of acting centrally with testosterone to suppress the secretion of LH in castrated rams and that cells containing mRNA for progesterone receptors are located in the hypothalamus of rams in the vicinity of GnRH neurons.

Analysis of Variance↗
PubMed2000

Laparoscopic intra-abdominal ligation of the testicular artery following castration in a horse.

A 364-kg (800-lb) 1-year-old mixed-breed horse was admitted for treatment of uncontrolled bleeding after castration. Multiple attempts to ligate the testicular artery through the scrotal incisions prior to referral had been unsuccessful. Because of the owner's concerns about cost, an attempt was made to control the bleeding by applying pressure to the inguinal region and administering formalin IV. However, hemorrhage continued. A decision was made to use laparoscopy to ligate the testicular artery. The horse was anesthetized and positioned in dorsal recumbency, and a routine ventral laparoscopic approach was used. The horse recovered without further complications. Laparoscopy should be considered for ligation of the testicular artery in horses with uncontrolled bleeding after castration.

Animals↗
PubMed2003

Postoperative hypoxemia and hypercarbia in healthy dogs undergoing routine ovariohysterectomy or castration and receiving butorphanol or hydromorphone for analgesia.

OBJECTIVE: To determine frequency and severity of postanesthetic hypoxemia and hypercarbia in healthy dogs undergoing elective ovariohysterectomy or castration and given butorphanol or hydromorphone for analgesia. DESIGN: Prospective trial. ANIMALS: 0 healthy dogs weighing > 10 kg (22 lb). PROCEDURE: Dogs were anesthestized with acepromazine, glycopyrrolate, thiopental, and isoflurane, and butorphanol (n = 10) or hydromorphone (10) was used for perioperative analgesia. Arterial blood gas analyses were performed 10 and 30 minutes and 1, 2, 3, and 4 hours after extubation. RESULTS: In dogs that received hydromorphone, mean PaCO2 was significantly higher, compared with the preoperative value, 10 and 30 minutes and 1, 2, and 3 hours after extubation. Mean PaCO2 was significantly higher in dogs given hydromorphone rather than butorphanol 10 and 30 minutes and 1 and 2 hours after extubation. Mean PaO2 was significantly lower, compared with preoperative values, 30 minutes and 1 and 2 hours after extubation in dogs given hydromorphone and 30 minutes after extubation in dogs given butorphanol. Mean PaO2 was significantly lower in dogs given hydromorphone rather than butorphanol 1 hour after extubation. Four dogs had PaO2 < 80 mm Hg 1 or more times after extubation. CONCLUSIONS AND CLINICAL RELEVANCE: Results suggest that administration of hydromorphone to healthy dogs undergoing elective ovariohysterectomy or castration may result in transient increases in PaCO2 postoperatively and that administration of hydromorphone or butorphanol may result in transient decreases in PaO2. However, increases in PaCO2 and decreases in PaO2 were mild, and mean PaCO2 and PaO2 remained within reference limits.

Analgesics, Opioid↗
PubMed1991

Effects of age and castration on activities of calpains and calpastatin in sheep skeletal muscle.

The objectives of this experiment were to assess effects of animal age and castration on activities of calpain I, calpain II, and calpastatin in sheep skeletal muscle. Ten newborn male lambs (2.9 kg), six weaned wethers (23.2 kg), six weaned rams (22.2 kg), six market wethers (55.4 kg), and six market rams (60.2 kg) were slaughtered and samples of biceps femoris were taken for assay of calpain I (micromolar calcium-dependent proteinase), calpain II (millimolar calcium-dependent proteinase), and calpastatin. Preweaning weight gain was similar for rams and wethers; however, postweaning ram growth exceeded (P less than .05) that of wethers. Ram biceps femoris weights at market were greater than those of wethers (P less than .05). Irrespective of age or gender, activity of calpain II was two- to threefold greater than that of calpain I. Muscle calpastatin activity was severa fold higher than calpain I and II activities. Activities of calpains and calpastatin declined (P less than .05) between birth and weaning. A portion of these losses were due to a dilution effect caused by accumulation of muscle proteins. Neonatal attenuation of calpain activities may underlie age-related attenuation of fractional rates of muscle protein degradation. Although ram muscle growth exceeded that of wethers, no differences (P greater than .05) in activities of muscle calpains or calpastatin were detected between these two groups at weaning or at market weight. Hence, castration did not influence lamb muscle growth by altering muscle calpain or calpastatin activities.

Aging↗
PubMed1987

Effect of photoperiod and castration on prolactin, testosterone and luteinizing hormone concentrations in male calves.

After 8 wk exposure to 8 h of light per day, prolactin (PRL) averaged 18.3 ng/ml of serum in eight male calves. Four calves then received 16 h of light per day; 6 wk later (age 14 wk) PRL averaged 93.8 ng/ml of serum, whereas PRL averaged 36.9 ng/ml of serum in four calves maintained under 8 h of daily light. By wk 20, PRL was not different in calves exposed to 16 or 8 h of daily light, averaging 34.7 and 17.2 ng/ml serum. Testosterone averaged .43 ng/ml of serum at wk 8 but was greater at wk 14 in calves receiving 16 h of light daily when compared with controls receiving 8 h of light (1.92 vs. .97 ng/ml of serum). Testosterone concentrations were not different between photoperiod treatments at wk 20. Luteinizing hormone (LH) concentrations were unaffected by photoperiod. In a second experiment, four male calves were castrated at approximately 2 wk of age while four similar controls were left gonadally intact. After 8 wk exposure to 8 h of light per day, PRL averaged 12.3 ng/ml of serum in all calves. After 6 wk exposure to 16 h of light per day, PRL in serum increased in castrates to 48.0 ng/ml and in controls to 59.8 ng/ml. We conclude that serum concentrations of PRL and testosterone, but not LH, increased in bull calves receiving 16 h of light daily relative to calves receiving 8 h of light, and that the PRL response to photoperiod is independent of the testes. However, 16 h light-induced stimulation of serum concentrations of prolactin is not maintained indefinitely.

Animals↗
PubMed1994

The estrogen receptor expression in the male rabbit urethra and prostate following castration.

The influence of castration on estrogen receptor (ER) expression in the male rabbit prostate and urethra, was investigated immunohistochemically and biochemically in 18 mature male, rabbits 14 days after bilateral orchiectomy, and in 15 controls. Immunohistochemical scores of ER were increased significantly in the prostatic stroma and the urethral submucosa (p < 0.05 Mann-Whitney), while the increase in the urothelium was not significant. Biochemically, the ER content was 87.4 +/- 42.6 f mol/mg protein in the normal prostate, and 190.0 +/- 28.0 f mol/mg protein following castration. The corresponding values for the posterior urethra were 228.3 +/- 43.2 f mol/mg protein and 354.9 +/- 60.1 f mol/mg protein. In both cases the increase was not significant. We conclude, that ERs in the prostate and the urethra of the male rabbit can be modified by hormonal manipulation. ERs may therefore be functionally active and not rudimentary.

Animals↗
PubMedDate not supplied

Effect of castration on metalloprotease activities in the lateral, dorsal, and anterior lobes of the rat prostate.

Several proteolytic enzymes are involved in mediating the regression of the prostate gland following castration. A previous study showed that plasminogen activator activities are elevated only in the ventral lobe by castration in the rat. Since matrix metalloproteases represent a different class of protease that degrade extracellular matrix, this study examined their activities in the lateral, dorsal, and anterior lobes of the rat in response to androgen deprivation. The results indicate that, in contrast to plasminogen activators, metalloprotease activities are increased in the lateral, dorsal, and anterior lobes following orchiectomy. This suggests that differences in regulation of certain proteases by androgens may occur in individual prostatic lobes.

Animals↗
PubMedDate not supplied

Effects of a restricted diet on in vitro spontaneous activity and glucose metabolism in isolated rat uterus. Influence of castration.

The effects of a restricted-diet (50% of the normal intake during 25 d) on the isometric developed tension (IDT), the metabolism of labelled glucose, and the levels of glycogen, of uteri isolated from ovariectomized (25 d) and non-ovariectomized rats were explored. The restriction of food intake produced a fall in the contractile activity of normal, non-ovariectomized, rats in permanent diestrous compared to normally fed rats in diestrous. On the contrary, in castrated rats, the IDT of isolated uterus from underfed rats, was significantly higher than its normal-fed controls. In normal rats the formation of 14CO2 from U 14C-glucose was significantly lower in uterine preparations from restricted-diet animals than the control one. On the other hand, in castrated rats, the formation of 14CO2 increased as a result of underfeeding. The post-incubation levels of glycogen in uteri from normal-fed animals diminished significantly in comparison to 0 time values. In uteri from rats subjected to a dietary restriction, the initial glycogen values were lower than in normal-fed controls, but they did not decline further after incubation in KRB medium. On the contrary, even when the levels of glycogen were significantly lower at 0 time than in diestrous animals, they diminished in ovariectomized rats after incubation, no matter the diet. The above results indicate that the effects of restricted-diet on contractile activity, levels of glycogen and glucose metabolism were not observed in ovariectomized rats. Further researches are needed to clarify that point.

Animals↗
PubMed1986

The influence of castration and methimazole on deoxyribonucleic acid content of the pituitary and thyroid glands of White Leghorn cockerels.

The pituitary gland of birds is known to increase in weight with castration and decreases with chemical thyroidectomy. Whether these changes are due to alterations in mitotic activity or to cell size changes has been examined by measurement of deoxyribonucleic acid (DNA) and protein content of these glands. The DNA content of the enlarge pituitary of castrated cockerels is the same as that in the pituitary of normal cockerels. The pituitary size increase may be due to an increase in gonadotrope size including any part of the gonadotrope population which may be obtained by recruitment of other basophils. The retardation in pituitary size and DNA content with methimazole treatment is probably due, at least in part, to growth retardation but may also be due, in part, to the conversion of larger basophils to smaller thyrotropes.

Animals↗
PubMed2000

Protein profiles in various epididymal segments of normal and castrated rats.

AIM: Epididymal proteins are known to play an important role in the maturation of spermatozoa. We ought to determine if there are regional differences in androgen-dependent epididymal proteins. METHODS: A group of adult rats was castrated and epididymides were removed three days following castration. The epididymides were dissected into caput, corpus and cauda segments, homogenized, and proteins were fractionated by anion exchange HPLC. Proteins in selected fractions were resolved by SDS-PAGE and visualized by silver staining. RESULTS: It was observed that the levels of multiple proteins drastically reduced in the various regions of epididymis of the orchiectomized rats. CONCLUSION: The epididymal proteins appear to be useful markers to study androgenic action in the epididymis.

Androgens↗
PubMed2001

[Perineal hernia in dogs--colopexy, vasopexy, cystopexy and castration as elective therapies in 32 dogs].

In 32 male dogs colopexy, vasopexy, cystopexy and castration was performed for the treatment of perineal hernia. Recurrence rate in this study is 22%, what is comparable to other studies using different methods. The degree of severity and the number of complications is lower with this technique than with others. Enlargement of the prostate was evident in 59% and bladder retroflexion in 22% of the dogs. A celiotomy allows to recognize, assess, reduce and fix displaced organs which is not possible by using other methods. The aim is to regain the tubular structure of the ampulla recti and to fix prostate and bladder cranioventrally to the pelvic entrance. The castration performed at the same time causes the prostate gland to atrophy within 2-3 weeks, what makes the pelvic entrance even wider and the dogs return to normal defecation.

Animals↗
PubMed2001

Quantitative evaluation of collagen and muscle fibers in the lower urinary tract of castrated and under-hormone replacement female rats.

OBJECTIVE: To evaluate the number of collagen and muscle fibers in the muscle layer of the urethra and in the bladder wall of castrated and under-hormone replacement female rats. METHOD: We studied 37 castrated female rats assigned to the following groups: Group C (n=9): received no medication; Group P (n=8) was given 0.1 ml of placebo, subcutaneous (SC) route; Group E (n=10): 17beta-estradiol, 10 microg/kg/day, SC route; Group PR (n=9): medroxyprogesterone acetate. 0.2 mg/kg/day, SC route; Group E+PR (n=9): association of 17beta-estradiol and medroxyprogesterone acetate. Sections were taken from the bladder wall and from the middle third of the urethra, and the specimens were stained with picrosirius for collagen and muscle fiber identification. RESULTS: Groups C and P showed a similar amount of collagen in the bladder and in the urethra, however greater than the other groups. Group E showed the smallest number of collagen fibers in the urethra. Groups E and E+PR presented a larger number of muscle fibers in the bladder. Group PR presented a larger number of muscle fibers than groups C and P, however smaller than groups E and E+PR. In the muscle layer of the urethra, the number of collagen fibers was smaller in Group E than in all the other groups, which were similar among one another. In regard to the urethral muscles, Group E was found to present the largest number of muscle fibers as compared to the other groups analyzed, while Group PR showed a significant decrease in the muscle layer, even in relation to the groups that were given no hormone medication. CONCLUSION: Estrogens significantly decrease the amount of collagen fibers, increase the amount of muscle fibers and determine a significantly decreased collagen/muscle ratio in both the detrusor muscle and in the urethral muscle layer. It is also noticed that isolated progestogen decreases the amount of collagen fibers and increases the number of muscle fibers in the detrusor muscle, but with less intensity than replacement with estrogens alone. It neither alters the number of collagen fibers nor decreases the muscle fibers in the muscle layer of the urethra, with increased collagen/muscle ratio in that structure. Finally, the estrogen-progestogen combination determines significantly decreased collagen fibers and increased muscle fibers in the detrusor muscle, causing no alteration to the collagen or muscle fibers in the muscle layer of the urethra.

Animals↗
PubMed2001

[Changes in lipid profiles in women after surgical castration during the fertile age].

OBJECTIVE: The main known risk factors for coronary heart disease in women, other than age, which is the most important risk factor of all, are cigarette smoking, raised blood pressure, obesity, diabetes and premature menopause, especially after ovarectomy. DESIGN: Retrospective clinical study. SETTING: Medical building, Prague 7, Department of Obstetrics and Gynecology 3rd Medical Faculty Charles University and Faculty Hospital Vinohrady, Prague 10. METHODS: In 1995 and 1996 we investigated plasma lipid levels and bone density in 75 women, 3 to 5 years after ovarectomy without HRT (group A). The results were compared with a control group (group B) of women of the same age and BMI. This group of women had normal menstruation periods. We investigated age, body mass index, bone density, total cholesterol, HDL and LDL cholesterol, ateroghenic index and triglycerides. RESULTS: When we compared groups A and B, there was a better result in all serum lipid levels in group B, but not significantly. In group A was more women with patological level of HDL-cholesterol. In group A there was a significantly lower level of bone density than in group B and there was an increase in the number of patients with osteoporosis in this group. CONCLUSIONS: Castration in premenopause had no influence in mean levels of parameters of lipid metabolism, but bone density significantly decreased after castration in this period.

Body Mass Index↗
PubMed2001

[Changes in pancreatic arginase activity in pubertal and adult rats induced by castration].

Arginase activity in kidney, and small intestine in several mammalian species is sensitive to castration, a finding that could suggest their dependence on testosterone. However, as far as we know, information on regulation of pancreatic arginase activity is scarce. In this paper, the effect of orchidectomy on pancreatic arginase activity in pubescent and adult rats was studied. Male pubescent and adult rats, 21 days old and 4 months old, respectively, were orquidectomizades and sacrificed at various times post-surgery. Groups of intact rats served as controls. Arginase activity and proteins were measured in pancreatic tissue. The activity of this enzyme was measured in serum in addition to glucose, triglycerides and total proteins. In pubescent rats pancreatic and serum arginase activities peaked at day 5 post-surgery, increased arginase activity in adult rats was seen at day 20. Changes in serum and pancreatic proteins in pubescent, but not in adult, castrated rats were observed. Taken together, these results suggest that pancreatic arginase activity is androgen-dependent and that there is age-difference, probably due lo distinct patterns of hormone secretion in pubescent and adult rats.

Age Factors↗
PubMedDate not supplied

Effect of castration on dehydroepiandrosterone-induced hepatocarcinogenesis in male rats.

Dehydroepiandrosterone (DHEA), a peroxisome proliferator, is a hepatocarcinogen in male and female rats. The incidence of DHEA-induced hepatic tumors was much higher in males compared to females, although the peroxisome proliferative effect is similar in both sexes. In this study, we have evaluated the effect of castration in male rats on DHEA-induced hepatocarcinogenesis. Orchiectomy resulted in a significant reduction in hepatocellular carcinomas (15% in castrated rats versus 81% in control rats). However, the incidence of neoplastic nodules was comparable in both orchiectomized and control groups (84% versus 94% in orchiectomized and control groups, respectively). Sixty-two percent of livers in the control group contained tumors larger than 10 mm compared to 8% in the orchiectomized group. These findings indicate that testosterone promotes the growth of neoplastic lesions induced by DHEA.

Animals↗
PubMed2002

Effects of the association of androgen/estrogen on the bladder and urethra of castrated rats.

PURPOSE: To study the effects of methyltestosterone, isolated or associated to estrogens, on the bladder and urethra of castrated adult rats. MATERIAL & METHODS: A total of 59 castrated animals were studied. They were divided into the following groups: I--placebo; II--equine conjugated estrogens; III--methyltestosterone and conjugated estrogens; IV--methyltestosterone. After 28 days of medication the animals were sacrificed and bladder and urethra cuts were obtained for the evaluation of the number of vessels, the thickness of the epithelia, and the quantity of collagen and muscular fibers. RESULTS: The group receiving the androgen/estrogen association presented a higher number of vessels, epithelial thickness and quantity of muscular fibers (p < 0.05). A smaller quantity of collagen fibers was observed in the group utilizing isolated conjugated estrogen (p < 0.05). CONCLUSION: We concluded that the association of androgen/estrogen positively modifies important parameters in the urinary continence mechanism. Therefore, it could constitute an option for hormone replacement in postmenopausal stress urinary incontinence cases.

Animals↗
PubMed2002

Bisphosphonates inhibit angiogenesis in vitro and testosterone-stimulated vascular regrowth in the ventral prostate in castrated rats.

Bisphosphonates (BPs) are used currently in the treatment of patients with bone metastases because these compounds inhibit bone resorption. We examined here the effects of BPs on inhibition of endothelial cell functions in vitro and in vivo. Treatment of endothelial cells with BPs (clodronate, risedronate, ibandronate, and zoledronic acid) reduced proliferation, induced apoptosis, and decreased capillary-like tube formation in vitro. Quantification of blood vessels in bone biopsy specimens from patients with Paget's disease before and after clodronate treatment showed a 40% reduction of the vascularization after BP treatment. However, such a decreased vascularity could be secondary to a reduction of bone resorption. Therefore, the tissue distribution of [14C]BPs in male rats was examined to develop an angiogenesis model in a noncalcified tissue where BPs could accumulate. [14C]BPs (zoledronic acid, ibandronate, and clodronate) not only accumulated in bone but also transiently accumulated in the prostate. The effects of BPs on testosterone-induced revascularization of the prostate gland in castrated rats were then studied. Testosterone in combination with ibandronate or zoledronic acid induced a 17-35% reduction of the prostate weight compared with castrated rats treated with testosterone alone. Blood vessel immunostaining on prostate tissue sections revealed that both ibandronate and zoledronic acid induced a 50% reduction of the revascularization of the prostate gland. Moreover, zoledronic acid did not alter testosterone-induced activity of a luciferase gene reporter construct transfected in androgen-dependent prostatic cells, indicating that this BP did not directly interfere with testosterone. In conclusion, BPs have in vivo antiangiogenic properties, which could be of relevance to improve therapy and prevention of bone metastasis. In addition, our results extend the potential clinical use of BPs to patients with early prostate cancer.

Angiogenesis Inhibitors↗