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PubMed2003

The evaluation of rat prostate blood flow using a laser speckle flowmetry: a comparative study using the microsphere method in castrated and androgen-replenished rats.

To evaluate the accuracy and reliability of laser speckle blood flowmetry in the measurement of prostate blood flow, we performed a comparative study with the ordinary intra-arterial radioactive microsphere injection method using the well-known castrate-rat model. Adult male Wistar strain rats were used for the study. The rats were either only castrated or subcutaneous testosterone replenishment was followed subcutaneously 6 h after castration. The prostate blood flow was measured at different time courses after castration. The effect of a single androgen replenishment on prostate blood flow was also evaluated. The measurement of prostate blood flow was performed by both the radioactive microsphere injection method and laser speckle blood flowmetry, and then the outcomes were compared. Rapid reduction in prostate blood flow to 30% of the normal level was observed 24 h after castration in the measurements with the microsphere injection technique. The prostate blood flow decreased gradually after 24 h post-castration to 23 and 21% of the normal level at 48 and 72 h after castration, respectively. The laser speckle blood flowmetry also detected the decrease in prostate blood flow well, but in a more gradual manner. The prostate blood flow was 70, 52 and 35% of the normal level at 24, 48 and 72 h after castration, respectively. The effect of a single administration of testosterone to castrated rats had recovered the prostate blood flow to 74 and 98% of the normal level by measurement with the microsphere injection technique and laser speckle blood flowmetry, respectively. The different outcome in blood flow rate change between the methods can be explained according to their different mechanism of measurement, thus suggesting the capillary vessels are the early and most responsive portion for hormonal manipulation. In conclusion, the laser speckle blood flowmetry is a convenient and reliable method for evaluating prostate blood flow, especially when the organ is required for other biological and molecular assays, since the method does not require the excision of the organ for the measurement.

Androgens↗
PubMed1990

Copulatory behavior of adult tamarins (Saguinus fuscicollis) castrated as neonates or juveniles: effect of testosterone treatment.

The sexual interactions of Saguinus fuscicollis males castrated as neonates, at 37 days of age, or prepubertally with adult intact females were studied. Prepubertally castrated males were observed while receiving testosterone, and while being treated with saline. Males castrated neonatally or at 37 days of age were observed while receiving testosterone. Neonatal castrates had previously been studied without hormone treatment and therefore no control condition was included for these animals. Prepubertally castrated males showed Mounts, Mounts with Thrusts, and Sexual Tongue Flicking when treated with saline only. In three of the four males, all measures of sexual behavior increased with testosterone treatment. Neonatally castrated males had failed to display any mounting or thrusting without testosterone treatment during a previous study. During the present study, three of the four males did not respond to testosterone treatment with sexual behavior. The fourth male and one male castrated at 37 days of age displayed some sexual behavior. These results suggest that most neonatally castrated males are not able to respond to testosterone with the activation of copulatory behavior. The findings are consistent with the hypothesis that in callitrichids the sensitive period for behavioral differentiation is shifted into neonatal life. However, some neonatally castrated males show a weak response to testosterone. This may reflect an extended and perhaps partially prenatal period of sensitivity.

Animals↗
PubMed1987

Prostate adenocarcinoma: effects of castration on in situ androgen uptake by individual cell types.

The cellular distribution of androgen uptake was investigated in normal prostate and in Dunning R3327H prostate tumors in Copenhagen rats in vivo at different time intervals after castration. Quantitative dry-autoradiography was used to demonstrate which cell types have androgen binding, and to quantify the amount of androgen binding per cell type during initial castration-induced tumor regression and subsequent tumor relapse. Regardless of time after castration, tumor stromal nuclei had significantly more 3H-dihydrotestosterone (DHT) labelling than did tumor epithelial nuclei (p less than .001). On the other hand, prostate gland epithelial nuclei showed more 3H-DHT binding than prostate gland stromal nuclei. Tumor stromal nuclei had greater DHT uptake than any other cell type measured in the tumor or in secondary sex organs at all times after castration. Different cell types responded differently to castration. The 3H-DHT uptake measured in tumor stromal nuclei after castration showed that one day after castration 14.6 +/- 2.1 silver grains were present, 14 days after castration 9.3 +/- 2.4 were seen, and 50 days after castration 18.9 +/- 1.8 were present. This significant increase from 14 days to 50 days is not seen in the other cell types. This study gives insight into the cellular androgen receptor distribution in normal and malignant rat prostate tissue.

Adenocarcinoma↗
PubMed2000

Vocal responses of piglets to castration: identifying procedural sources of pain.

The aims of this study were to identify which aspects of castration are painful to piglets, and to determine if less painful methods are available. Previous work has shown that piglets produce more high frequency calls (>1kHz) when castrated than when handled identically but not castrated, or when castrated using a local anesthetic. In Experiment 1, we used 90 piglets to assess the vocal responses to different components of the castration procedure: restraint, washing the ano-genital region, scrotal incision, and pulling/severing of the spermatic cords. Compared to sham-operated animals (which were restrained and washed but not castrated) incision of the scrotum produced much more high-frequency calling than restraint alone at the same stage of the procedure. Pulling and severing the spermatic cords evoked the greatest amount of calling, significantly more than the incision, regardless of the order in which the incision and pull/sever were performed (P<0.001). In Experiment 2 (49 piglets), we found no difference in calling between two methods routinely used to sever the spermatic cord: cutting the cord with a scalpel versus tearing the cord by pulling on the testicle. These findings suggest that the pulling and severing of the spermatic cords are the most painful components of castration, yet altering the method of severing resulted in no change in call rate. Rather than focusing on pain control, welfare problems associated with castration may be better reduced by using non-surgical approaches, or by eliminating the need for castration in the first place.

Journal Article↗
PubMed1997

Combined castration and fractionated radiotherapy in an experimental prostatic adenocarcinoma.

PURPOSE: The present study using the Dunning R3327-PAP rat prostatic adenocarcinoma model was designed to study the effect on tumor growth of castration prior to or after irradiation with 20-25 Gy as compared with either irradiation or castration alone. METHODS AND MATERIALS: Rats were bilaterally orchidectomized. During the irradiation procedure the nonanesthetized animals were held in a metallic frame with a strong cotton net and they were observed by means of a video camera. The suboptimal irradiation dose was given once daily with a 4-MeV linear accelerator, 4-5 Gy/fraction, during 5 consecutive days. Tumor volumes and rat weights were followed. At the end point of the study the animals were sacrificed and the tumors were morphometrically analyzed. RESULTS: The combination of irradiation and castration delayed tumor regrowth better than irradiation alone with the same suboptimal dose. Castration before irradiation delayed tumor regrowth more efficiently than castration after irradiation. However, castration alone delayed tumor regrowth even more effectively than suboptimal irradiation doses combined with castration. CONCLUSIONS: In combination with suboptimal irradiation neoadjuvant androgen deprivation was more inhibitory to rat prostatic adenocarcinoma regrowth than adjuvant androgen deprivation. Irradiation with suboptimal doses combined with castration may cause an earlier relapse to androgen-independent tumor growth than castration alone.

Adenocarcinoma↗
PubMed2002

Castration in female rats modifies the development of the pilocarpine model of epilepsy.

Previous studies have shown that the susceptibility to pilocarpine-induced status epilepticus (SE) in female rats changes according to estrous cycle phases. These studies have also shown that following pilocarpine administration changes occur in gonadal, hypophyseal and hypothalamic hormones that could contribute for the sequence of the epileptic events. Accordingly, the present work aimed to investigate the role of sexual hormones withdrawal on the development of the pilocarpine model of epilepsy in female rats. With this purpose, castrated and non-castrated adult female Wistar rats were injected with pilocarpine and some characteristic parameters of the experimental model were observed. The results showed increased mortality after pilocarpine injection in the castrated rats when compared with non-castrated females. The latency period for SE onset and for the first spontaneous seizure was decreased in castrated when compared with non-castrated animals. The mossy fiber sprouting measured by neo-Timm scale during the chronic period, reached grade 3 for castrated epileptic rats while the non-castrated epileptic rats showed grade 2. Our results indicate that castration interferes with the epileptogenesis in the pilocarpine model of epilepsy suggesting that female sexual hormones could have protective effects against pilocarpine-induced SE.

Animals↗
PubMedDate not supplied

Effect of castration on serum concentrations of gonadal hormones, insulin-like growth factor-I and its binding proteins in male pigs.

Ten male pigs (Large White x Landrace), 7 months old, were randomly allocated to two experimental groups. Five of them were castrated and the other five served as controls. Sera were collected on the day of castration and 1, 5, 6 and 7 weeks after castration for hormone assay. There was a significant rise in the splenic and pancreatic weights in the castrates (P < 0.01). The weights of prostate, seminal vesicles and bulbourethral glands were significantly decreased (P < 0.01) in the castrates, which is attributed to a fall in testosterone levels (P < 0.001). The fall in oestradiol concentrations (P < 0.001) in castrates confirms that the testis is the major source of oestrogens in males. Although there was no significant change in the body weight, serum IGF-I levels were elevated in the castrates as compared to the controls after 5, 6 and 7 weeks (P < 0.001). IGFBP bands of 43 and 39 kda predominate in both control and experimental groups indicating that castration had no effect on the IGFBP pattern. It is suggested that the increase in IGF-I levels may be due to uncoupling of GH/IGF-I axis induced by the decrease in steroid concentrations due to castration.

Animals↗
PubMed1998

Inhalation anaesthesia for the castration of piglets: CO2 compared to halothane.

General anaesthesia with 80% CO2/20% O2 and 5% halothane in O2 (mask induction) was compared for castration of 3-4 week-old piglets. One group was castrated without anaesthesia. Of the noncastrated control groups one had CO2- and one halothane anaesthesia, one breathed room air through the induction system, and one was held in castration position. The behaviour to induction and castration was assessed, and the cortisol-, ACTH- and beta-endorphin plasma concentrations were determined to quantify the stress elicited by anaesthesia, castration and handling. Violent struggling and vocalization were elicited by CO2 and positioning into the mask induction system while breathing room air; halothane induction was quiet. CO2 induced profound surgical anaesthesia; whereas under halothane anaesthesia some animals exhibited still a slight reaction to castration. Recovery was fast, smooth and quite. Permanent violent struggling and vocalization were elicited by castration without anaesthesia. Plasma cortisol was not a sensitive tool to judge castration stress. The high ACTH and beta-endorphin plasma concentrations elicited by CO2 anaesthesia confirm our clinical experience. General anaesthesia is fast and safely induced with CO2 in piglets and castration can be performed without any reaction, but with CO2 anaesthesia the stress is not reduced.

Anesthesia, Inhalation↗
PubMed2001

Analgesia of newborn lambs before castration and tail docking with rubber rings.

This study assessed the effects of suckled sucrose and parenteral carprofen treatment on behavioural measurements of discomfort and serum haptoglobin concentration in lambs following rubber ring castration and/or tail docking. Twenty-eight male and 20 ewe lambs were allocated to either a male or ewe lamb control group (n=4) or to one of three male and two ewe lamb treatment groups (n=8). Male lambs in one treatment group received carprofen subcutaneously (0.5 mg/kg) 30 minutes before castration and docking. Lambs in all other treatment groups suckled sucrose or colostrum immediately before castration and/or tail docking. Behavioural measurements of discomfort were made following castration or tail docking in treatment groups and also in control animals which were not castrated or tail docked. Blood sampling of animals in treatment groups for analysis of serum haptoglobin, an acute phase protein used as an indicator of an acute inflammatory response, was performed before castration or docking and at 24 and 48 hours after castration or docking. Control lambs were blood sampled at 0, 24 and 48 hours following behavioural assessment Neither suckled sucrose nor carprofen treatment altered discomfort behaviour associated with castration or tail docking. Haptoglobin levels following castration or tail docking remained close to the detection limits of the assay and were similar to those recorded in control animals.

Analgesics, Non-Narcotic↗
PubMed1988

Enhanced fever following castration: possible involvement of brain arginine vasopressin.

Arginine vasopressin (AVP) is thought to act as an antipyretic in the ventral-septal area (VSA) of the brain. As AVP content of this area has been shown to be virtually eliminated following long-term castration, we have tested the hypothesis that castrated rats would display enhanced fevers. Four months after castration (or sham castration), male Wistar rats were given prostaglandin E1 (200 ng), purified interleukin 1 (25 U), or saline (5 microliters) into a lateral cerebral ventricle. Castrated rats displayed fevers of longer duration, reflected as significantly enhanced thermal indexes, than did age-matched sham-operated controls. Castrated rats also were less able to defend their body temperatures to ambient heat stress but not to ambient cold. AVP content of VSA and lateral septum, but not of hippocampus, of castrated rats was significantly reduced; oxytocin content of the three areas was unchanged following castration. These data support earlier studies concerning effects of castration on septal AVP content and are consistent with the possibility that AVP is an antipyretic in the VSA of the rat.

Alprostadil↗
PubMed1985

The effects of dichloromethylene biphosphonate on osteoporotic femora of adult castrate male rats.

In a previous study we reported that castration of adult male rats resulted in femoral osteoporosis 4 months later. The present study tested the effects of dichloromethylene biphosphonate (Cl2MBP, formerly Cl2MDP), a bone resorption inhibitor, on the development of osteoporosis in femora of adult castrated male rats. One-year-old male Holtzman rats were assigned to three groups: sham-operated controls; castrated-no treatment; castrated + Cl2MBP injections 3 times/week. The animals were sacrificed 4 months later. Femora from untreated castrated rats were osteoporotic, confirming our earlier study. Femora from Cl2MBP-treated castrates did not differ from those of controls and were significantly denser and more robust than those of untreated castrated rats. The results indicated that Cl2MBP treatment started immediately after castration prevented the development of femoral osteoporosis in adult castrated male rats.

Animals↗
PubMed1987

Differential in vitro stimulation by naloxone and K+ of luteinizing hormone-releasing hormone and catecholamine release from the hypothalami of intact and castrated rats.

We compared the effects of an opiate receptor antagonist, naloxone (NAL), on in vitro LHRH and catecholamine release from the medial basal hypothalamus-preoptic area (MBH-POA) of intact and castrated adult male rats. The MBH-POA (six per chamber) were perifused in vitro for 6 h. After 1 h of preincubation, basal LHRH, dopamine (DA), norepinephrine (NE), and epinephrine (E) release were estimated in perifusates collected during the second and third hours. During the fourth hour, chambers were perifused for 30 min with medium alone or medium containing NAL; tissue viability was confirmed during the sixth hour by adding 60 mM KCl to the medium. Tissue samples were weighed at the end of the perifusion and homogenized in 0.1 N HCl for subsequent analyses of LHRH contents. The basal release rate and cumulative hourly LHRH output from the MBH-POA of intact rats was about 3 times that from castrated rats (P less than 0.05). The NAL pulse stimulated LHRH release from the MBH-POA of intact and castrated rats (P less than 0.05); the amount released by the MBH-POA of intact rats was significantly higher than that from castrated rats (P less than 0.05). These differential LHRH release responses reflected the differences in the MBH-POA LHRH concentrations that normally occur between intact and castrated rats and also estimated at the end of the perifusion. In contrast to the LHRH response, the basal release rate and hourly output as well as NAL-induced DA release from the MBH-POA of intact and castrated rats were similar. On the other hand, as in the case of LHRH, basal NE release and hourly output from the MBH-POA of castrated rats were significantly reduced compared to those from the MBH-POA of intact rats (P less than 0.05). In addition, NAL promptly stimulated NE release, and the amount released was higher from the MBH-POA of intact rats (P less than 0.05). The basal amount of E released from the MBH-POA of intact and castrated rats was near or below the level of sensitivity of the assay. However, NAL increased E release from the MBH-POA of both groups of rats, and E output was apparently 2-fold higher from the MBH-POA of intact than castrated rats. Prior perfusion with morphine failed to block NAL-evoked stimulation of LHRH release from the MBH-POA of intact rats.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1990

Effects of castration on luteinizing hormone and follicle-stimulating hormone secretion by pituitary cells from male rats.

Because the role of the pituitary in the testicular control of gonadotropin secretion remains controversial, we examined the effects of castration on the release of LH and FSH under basal conditions and in response to GnRH stimulation by dispersed pituitary cells in monolayer culture as well as by cells perifused with pulses of GnRH. These effects were compared to changes in LH beta, FHS beta, and alpha-subunit mRNA levels determined by Northern blot analysis. Pituitary cells were prepared from 7-week-old intact rats and rats orchidectomized 2 weeks previously. Castration increased basal FSH secretion from monolayer cultures, interpulse FSH release from perifused pituitary cells, FSH beta mRNA concentrations and serum FSH levels each approximately 2-fold, whereas pituitary FSH contents were similar in cells from intact and castrated rats. Pituitary LH content rose 3-fold, LH beta mRNA rose 5.6-fold, and basal LH secretion increased 6-fold, but serum LH levels increased 22-fold. Thus, the change in FSH synthesis inferred from the increase in FSH beta mRNA was proportional to the increase in FSH secretion both in vitro and in vivo. Whereas the basal release of LH in vitro was also proportional to the change in LH beta mRNA, secretion of LH in vivo exceeded these changes, underscoring the importance of increased GnRH to the serum LH castration response. Castration resulted in an increase in the sum of FSH content and secretion during 10 days in culture in the absence of GnRH, indicating ongoing FSH synthesis. Total LH declined in cells from intact rats, and this decline was prevented by castration; this effect may be due to a castration-related decrease in intracellular LH degradation or increased LH synthesis in the absence of GnRH. Castration also augmented the GnRH-stimulated release of LH and FSH from monolayer cultures 4.5- and 1.8-fold, respectively, and increased the amplitude of GnRH-stimulated LH and FSH pulses 5- and 2-fold in experiments with perifused pituitary cells. The EC50 for GnRH was unaffected by castration.(ABSTRACT TRUNCATED AT 400 WORDS)

Animals↗
PubMed1988

Effect of time after castration on secretion of LHRH and LH in the ram.

Hypophysial portal blood and peripheral blood were obtained from conscious, unrestrained rams to measure simultaneously the secretion of LHRH and LH in entire rams and rams which had been castrated for 2-15 days (short-term castration) and for 1-6 months (long-term castration). The apparatus for portal blood collection was surgically implanted using a transnasal trans-sphenoidal approach and, 4-5 days later, portal blood and peripheral blood were collected simultaneously at 10-min intervals for 8-9 h from 15 sheep. LHRH was clearly secreted in pulses in all three physiological conditions, but there were marked differences in pulse frequencies, which averaged 1 pulse/2-4 h in entire rams, 1 pulse/70 min in short-term castrated rams and 1 pulse/36 min in long-term castrated rams. In entire and short-term castrated animals, LH profiles were also clearly pulsatile and each LHRH pulse in hypophysial portal blood was associated with an LH pulse in the peripheral blood. In long-term castrated animals, LH pulses were not as well defined, because of the high basal levels and small pulse amplitudes, and the temporal relationship between LHRH and LH pulses was not always clear. These results demonstrate the pulsatile nature of LHRH secretion under the three physiological conditions and suggest that the irregular LH profiles characteristic of long-term castrates are due to an inability of the pituitary gland to transduce accurately the hypothalamic signal. The very high frequency of the LHRH pulses may be one of the major reasons for this, and is probably also responsible for the high rate of LH secretion in the long-term castrated animal.

Animals↗
PubMed1986

Effects on growth and body composition of androgen deprivation by castration or autoimmunization to LH-releasing hormone in the male rat under conditions of controlled food intake.

The effects of endogenous gonadal hormones on the regulation of body composition and energy retention have been investigated under conditions of controlled food intake. Male and female rats were fed the same amount from weaning to 82 days of age. The carcases of males contained more protein, less lipid and yielded more ash than females, but they had the same amount of total energy in their carcases as females. In a second experiment, male rats were sham-operated or castrated at 19 days and then fed equal amounts from weaning. At 40 days, intact and castrated rats did not differ in total carcase energy content nor in carcase composition. At 82 days the carcases of intact rats had more protein but had retained the same amount of energy as castrated rats. By 131 days, the difference in protein content was larger and intact rats had less carcase lipid, less carcase energy and gave less ash than castrated rats. At the same age and with a similar food intake, the differences in carcase composition between intact males and females were considerably larger than between intact and castrated males. In a third experiment, male rats were sham-operated or castrated at 1 day post partum and fed the same amount as in the second experiment from weaning to 82 days. Both sham-castrated and castrated rats grew less well than rats operated on at 19 days. The differences in carcase composition between intact and castrated rats were in the same direction but of greater magnitude than in rats operated at the later age.(ABSTRACT TRUNCATED AT 250 WORDS)

Androgens↗
PubMed1992

Performance and health of weanling bulls after butorphanol and xylazine administration at castration.

A total of 268 crossbred, 6- to 9-mo-old, bull calves (214 +/- 19 kg) were used in two separate 27-d experiments to assess the effects of butorphanol and xylazine administration (BXA) on the subsequent performance and health of beef calves. In each experiment, calves were randomly allotted to four treatment groups: 1) castration with BXA, 2) castration without BXA, 3) no castration with BXA, and 4) no castration without BXA. There were two replicates within each experiment. The intravenous administration of .07 mg/kg of butorphanol and .02 mg/kg of xylazine occurred 90 s before tail hold and castration procedures. Calves were placed in a squeeze chute and manually restrained by tail elevation. In Exp. 2, the cattle also were scored for chute activity (on a 1 to 5 scale with 5 being the most active). Cattle were weighed at the beginning and end of the experiment, feed intake was recorded daily, and cattle were monitored daily for respiratory disease. There were no castration x BXA interactions (P greater than .51). Castration reduced (P less than .01) daily gain and gain/feed and tended (P = .13) to reduce feed intake. The administration of BXA had no effect (P greater than .05) on gain or gain/feed but did tend (P = .13) to reduce feed intake. No differences (P greater than .45) were observed in morbidity or mortality due to either BXA or castration. Castration and BXA increased (P less than .01) blood cortisol levels on d 3, whereas control animals had reduced cortisol levels.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗
PubMed1985

Castration method and progesterone-estradiol implant effects on growth rate of suckling calves.

Eighty male calves nursing their dams and averaging 15 d of age were used to evaluate a method of nonsurgical castration and a growth implant in a 196-d experiment. On the 1st d of the experiment, 40 calves were castrated chemically using Chem-Cast (active ingredient: lactic acid 88% wt/wt), and 40 were castrated surgically. Twenty calves on each castration treatment were implanted with STEER-oid on d 1 and reimplanted on d 121 while 20 calves on each treatment were not implanted on either date. Chemical castration resulted in significantly lower scrotal edema and a trend toward increased rate of gain at d 28. Castration treatment did not affect 196-d rate of gain and weaning weights of calves. On d 121, bilateral castration was determined in 30 of 40 chemically castrated calves, a condition that persisted on d 196, resulting in a 75% castration rate. Implanted calves had rates of gain that were 14, 6, and 4% higher, respectively, on d 28, 121, and 196 compared with unimplanted calves.

Animal Population Groups↗
PubMed2001

[The change of tear secretion and tear film stability in castrated male rabbits].

OBJECTIVE: To evaluate the effect of androgen on tear secretion and tear film stability by observing the changes of ocular surface and tear film in the castrated male rabbit. METHODS: Sixteen male rabbits were selected and randomly divided into the normal control group (8 rabbits) and the castrated group (8 rabbits). Schirmer's tests, tear film break-up time (BUT) and rose bangle (rb) staining were performed on the eyes of two groups at 1, 2, 3, 4 weeks, 2 and 3 months. The Chiron Diagnostics ACS: 180 Automato Chemilluminescence Systems was used to determine the two groups' testosterone level in serum at pre-castrate and post-castrate. Results were analyzed statistically. Lacrimal gland, Harder's gland, conjunctiva, cornea and limbus were removed for observation histopathologically after three months. RESULTS: Both Schirmer's test and break-up time scores were significantly lower in the castrated group compared with the control group. The difference became more and more prominent in the course of observation. Rose bangle staining was positive in the castrated group. Testosterone level in serum was significantly lower in the post-castrate than that in the pre-cartrate. Histopathological observation showed that lacrimal glandular epithelial cells were atrophic and flat, the lumen of gland was enlarged and vesicular mucous in acinus cells disappeared. PAS positive material and conjunctival globlet cells were significantly decreased in the castrated group. Compared with the control group there were no significant morphologic changes in the corneal epithelium and limbal stem cells. CONCLUSIONS: The low level of testosterone in castrated rabbit may contribute to the atrophy and applanation of lacrimal glandular epithelium, disappearance of vesicular mucous in acinar cells and the significant decrease of the number of conjunctival globlet cells. All these can lead to decrease of both the quantity and quality of tear secretion and thus cause the instability of tear film.

Androgens↗