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PubMed1990

Immunoreactive luteinizing hormone-releasing hormone in the frog (Rana esculenta) brain: distribution pattern in the adult, seasonal changes, castration effects, and developmental aspects.

The present work describes the neuroanatomical distribution of the immunoreactive luteinizing hormone-releasing hormone (ir-LHRH) system in the brain of adult male and female, castrated male and developing Rana esculenta. No obvious sex differences in the distribution pattern of ir-LHRH were observed. Immunoreactive neuronal cell bodies are not contained within a single anatomically defined area of the brain. They are present as distinct groups in the olfactory bulbs, medial septal area, anterior preoptic area (APOA), retrochiasmatic area of the infundibulum, and interpeduncular nucleus-tegmentum area. Of the entire brain, the medial septal-APOA region exhibits the highest frequency of ir-LHRH cell bodies in both sexes. ir-LHRH fiber projections are present in the olfactory bulbs, medial septal area, APOA, floor of the diencephalon, subhabenular-periventricular area in the epithalamus, lateral suprachiasmatic area, ventrolateral infundibulum, median eminence, pars nervosa, optic tectum, interpeduncular nucleus-tegmentum area, and rhombencephalon grey. Castration seems to bear no effect on the pattern of ir-LHRH system in the frog brain. The influence of castration consisted in decreased intensity of the immunostaining and frequency of occurrence of the septal-APOA neuronal cell bodies. In median eminence, castration also induced a sensible decrease in the immunoreactivity, whereas in the pars nervosa of 50-day castrates ir-LHRH fibers totally disappeared. During ontogenesis, ir-LHRH elements first become evident in stage 31 tadpoles (beginning of metamorphic climax); LHRH immunoreaction is restricted to the cell bodies and fibers in the APOA and some fibers in the ventral hypothalamus and a few in median eminence. This condition remains unaltered until stage 33 when the tail is almost totally resorbed. The possible implications of the ir-LHRH-containing brain areas in the different aspects of reproduction in the frog are briefly discussed.

Animals↗
PubMed1976

Effects of castration, testosterone and immobilization on the activities of choline acetyltransferase and cholinesterase in rat limb muscles.

Thirteen months after castration of male rats the weight of their soleus muscles was lowered to 82% and their choline acetyltransferase (ChAc) activity to 83% of control values. The administration of testosterone lasting 5 weeks increased the weight of the soleus muscles of castrated animals by 19% and their ChAc activity bu 37%. Changes in the activity of cholinesterase occurring after castration and testosterone treatment were not statistically significant. It is assumed taht the effect of testosterone on the activity of ChAc was mainly due to an increase in the functional activity of the motoneurones innervating the muscle. Rapid developmental increase of ChAc activity was observed in the muscles of intact rats between the age of 48 and 82 days. During this period of development the activity of ChAc rose faster than the weight of the muscles. Testosterone had no effect on the weight and ChAc activity of the soleus and extensor digitorum longus muscles of non-castrated rats after 1 week's administration; after 5 weeks' administration the weight of the muscles and their ChAc activity were diminished. After the soleus muscles of non-castrated rats had been immobilized for 10 days, their ChAc activity was 56% and their weight 51% of control values. The administration of testosterone did not alter the effect of immobilization on the ChAc and weight of the muscle.

Acetyltransferases↗
PubMed1984

Plasma lipoprotein responses to castration and androgen substitution in rats.

To elucidate plasma testosterone/lipoprotein relationships in a controlled animal experiment, whole-plasma lipid concentration and amount of lipoprotein components in five density classes were determined in three groups of rats: normal control rats, short-term castrated rats, and rats treated with testosterone propionate after castration. Compared to control rats, whole-plasma total cholesterol, free cholesterol (FC), cholesteryl-ester (CE), and phospholipids (PL) rose in castrated rats but were normalized in rats receiving androgen substitution. There were no group differences in whole-plasma triacylglycerol concentration. The levels of protein, FC, and CE in LDL (d = 1.006 to 1.063 g/mL) and HDL2b (d = 1.063 to 1.100 g/mL) of castrated rats were appreciably higher than in LDL and HDL2b of control rats. In androgen-substituted rats the level of LDL and HDL2b protein, FC, CE, and PL were all reduced to normal or subnormal levels. The esterified fraction of cholesterol in whole plasma was increased by androgen treatment. There were no significant group differences in VLDL (d less than 1.006 g/mL), HDL2a (d = 1.100 to 1.125 g/mL) or in HDL3 (d = 1.125 to 1.210 g/mL). The results suggest that short-term castration of rats is followed by hyperlipoproteinemia due to lack of testosterone and that the lipoprotein changes mainly reside in LDL and the less-dense type of HDL.

Animals↗
PubMed1983

The effects of differential housing, castration and steroidal hormone replacement on attacks directed by resident mice towards lactating intruders.

Group-housed castrated (but not intact) males show high incidences of attack on lactating (but not non-lactating) female intruders. In Experiment 1, responses by isolated and group (in 3's)-housed intact and castrated males to lactating intruders were studied. The latter males were given sham, testosterone (T) or estradiol (E2) implants before testing. Castration augmented attack by animals in both housing conditions, confirming that intra-group fighting could not account for androgen-related changes in fighting behaviour in group-housed animals. Both T and E2 implants suppressed attack in animals in both housing conditions. Consequently, Experiment 2 evaluated the influence of three dose levels of T, E2 and DHT (dihydrotestosterone), in attack by castrated group-housed male residents on lactating intruders. Treatment of castrated males with T or E2 (but not DHT) inhibited attack in these animals. These findings provide support for the idea that aromatization is also a prerequisite for the inhibitory action of T on male aggression towards lactating females.

Aggression↗
PubMed1984

Perseveration of attention to conspecific odors and novel objects in castrated gerbils.

Castrated male and female gerbils were tested for odor preference and for attention to conspecific odors and a novel object. Castrated gerbils housed with sham-operates preferred home odors, discriminated between two groups of male gerbils by olfactory cues, and perseverated in attention to odors of male gerbils and to a novel object. Similar perseveration to male conspecific odors was shown in gerbils given injections of L-DOPA (30 mg/kg). Combined treatment (castration and L-DOPA) resulted in additive effects on perseveration. This research challenges two general hypotheses of gonadal hormone function. The first, that changes in odor preference after castration are due to a loss in testicular androgen, is insufficient, because (1) female as well as male gerbils showed similar perseveration to odors, (2) there was a significant correlation between LH and duration of investigation of male conspecific odors, and (3) L-DOPA, the dopamine precurser, also caused perseveration to conspecific odors. The second, that gonadal hormones are responsible for persistence of attention, cannot be broadly generalized, because castration with resultant elevation of LH and regression of ventral glands resulted in perseveration of attention in male and female gerbils.

Animals↗
PubMed1988

Hormonal restoration of masculine sexual behavior in long-term castrated B6D2F1 mice.

In contrast to the facilitative effects reported for other rodents, testosterone treatment at the time of castration previously was reported to inhibit masculine sexual behavior in male B6D2F1 mice. Males of this genotype vary in their behavioral response to castration. Some castrates retain sexual behaviors for many weeks after surgery, whereas others do not. In the present study, we sought to determine the effects of exogenous steroid hormone treatment on castrated B6D2F1 mice that had ceased to show copulatory behavior. Testosterone propionate and estradiol benzoate restored copulatory behavior to precastration levels in B6D2F1 males that did not retain sexual behaviors after castration.

Animals↗
PubMed2005

Repercussions of castration and vasectomy on the ductal system of the rat ventral prostate.

Diseases, such as cancer and benign prostatic hyperplasia, are related to disruption of the mechanism regulating the balance between cell proliferation and apoptosis in prostatic cells. Since castration and vasectomy might alter that balance, this study evaluates the cell proliferation, apoptosis and height of the secretory epithelium of the ventral-prostate ductal system post-castration and vasectomy. Immunohistochemical (PCNA and Ki67), cytochemical (Fuelgen reaction) and morphometric investigation have been carried out. Cell proliferation indices decreased significantly in both regions of the ventral-prostate ductal system after castration compared to the sham-operated group. The apoptotic index increased significantly after 48 h, declining 7 days post-castration. The cell proliferation indices did not differ after 48 h significantly; however, they increased 7 days post-vasectomy in both regions. The apoptotic index did not differ significantly in either time post-vasectomy. Castration caused an imbalance in favor of apoptosis, whereas vasectomy caused an imbalance in favor of cell proliferation.

Animals↗
PubMed2004

Prevention by 17beta-estradiol and progesterone of calcitonin gene-related peptide-induced elevation of skin temperature in castrated male rats.

OBJECTIVES: To clarify the relationship between calcitonin gene-related peptide (CGRP) and ovarian hormones (17beta-estradiol and progesterone) in hot flashes in men who undergo androgen deprivation therapy for prostate cancer, we studied the effects of ovarian hormones on CGRP-induced elevation of skin temperature in castrated male rats. The results were compared with those from rats treated with testosterone replacement. METHODS: Adult male rats were castrated by either a single injection of gonadotropin-releasing hormone analogue (Leuplin, 1.0 mg/kg, subcutaneously) or bilateral orchiectomy. The castrated animals were subcutaneously injected daily for 14 days with ovarian hormones, testosterone, or olive oil as the vehicle. On the day after the final administration of the drug, the changes in skin temperature induced by exogenous CGRP (10 mug/kg intravenously), serum testosterone concentration, and prostate weight were measured. RESULTS: The CGRP-induced elevation of skin temperature was significantly greater in the castrated rats than in the sham-treated rats. This potentiation was significantly inhibited by treatment with ovarian hormones, as well as by testosterone replacement. The testosterone replacement restored decreases in both the serum testosterone level and the prostate weight due to castration; the treatment with ovarian hormones did not affect them. CONCLUSIONS: 17beta-Estradiol and progesterone, which do not confer testosterone activity on serum, may be useful for the treatment of hot flashes in patients for whom testosterone replacement therapy is contraindicated, such as those with prostate carcinoma. In addition, we suggest that CGRP is closely involved in the amelioration of hot flashes by ovarian hormones in men who undergo androgen deprivation therapy.

Animals↗
PubMed2005

Effects of testosterone metabolites on copulation, medial preoptic dopamine, and NOS-immunoreactivity in castrated male rats.

The medial preoptic area (MPOA) is an important integrative site for male sexual behavior. Dopamine (DA) is released in the MPOA of male rats shortly before and during copulation. In a previous study, we identified 17beta-estradiol (E(2)) as the metabolite of testosterone (T) that maintains MPOA basal extracellular DA levels. However, the presence of dihydrotestosterone (DHT), an androgenic metabolite of T, is required for the female-induced increase in MPOA DA observed during copulation. Recently, we reported that assays of MPOA tissue DA content showed that castrates actually had more stored DA than did gonadally intact males. Therefore, the reduction in extracellular levels in castrates was not due to decreased availability of DA; most likely it was due to decreased release. Furthermore, T upregulates neuronal nitric oxide synthase (nNOS) in the MPOA. NO has been implicated in the regulation of DA release in the MPOA. It is not known, however, which metabolite(s) of T regulate(s) tissue stores of DA and/or nNOS in the MPOA of male rats. The present experiments were designed to test the following: (1) whether E(2), DHT, or the combination of the two influences MPOA DA tissue levels, an indication of stored DA, in male rat castrates; and (2) whether E(2), DHT, or the combination of the two influences NOS-ir in the MPOA of castrated male rats. The results indicate that E(2) up-regulates nNOS-ir in the MPOA and maintains tissue content of DA at levels similar to those in T-treated rats. DHT did not influence nNOS-ir, while attenuating the effect of castration on tissue DA content.

Analysis of Variance↗
PubMed2005

Castration reduces male testosterone, estradiol, and territorial aggression, but not paternal behavior in biparental dwarf hamsters (Phodopus campbelli).

Biparental male hamsters, Phodopus campbelli, act as midwives during the birth of their litter and are highly responsive to an experimentally displaced pup. They also have high peripheral concentrations of estradiol, a hormone with known roles in maternal behavior. Surgical castration during the gestation of their first litter was used to investigate the source of that estradiol and the functional role of testicular sex steroids in paternal responsiveness. In Experiment I, castration reduced both testosterone and estradiol concentrations, confirming that the testes were the primary source of estradiol. However, neither paternal responsiveness nor multiple measures of reproductive success were altered by the castration. Aggression directed towards an intruder, however, was reduced by castration. In Experiment II, removal of prior experience with birth or pups also failed to alter paternal responsiveness in castrated males. Although the present results do not preclude a role for local estradiol synthesis in the brain, results do not support an association between high circulating estradiol in males and their paternal behavior.

Aggression↗
PubMed1982

Delay of castration induced regression in rat prostate by pituitary homografts.

Although prolactin has a synergistic effect with testosterone in stimulating growth of the lateral lobe of the rat prostate, the role of prolactin in the absence of testosterone has not been well established. We studied the effect of prolactin on the rate of prostatic regression induced by castration in mature Sprague-Dawley rats. Anterior pituitaries from female rats were transplanted under the renal capsule in all rats. Castration and unilateral nephrectomy were carried out 1 week later. Half of the animals had the normal, non-grafted kidney removed and another half had the kidney bearing the pituitary grafts excised. Rats were sacrificed on days 0, 7, 10 and 14 and 3 lobes of the prostate were dissected separately. The lateral lobe showed a marked decrease in the rate of regression in the pituitary graft-bearing rats. In control animals, the relative weight of the lateral lobe on days 7, 10 and 14 was 38 +/- 2 per cent (mean +/- SE), 33 +/- 2 per cent and 26 +/- 2 per cent of the day 0 value, respectively; the respective relative weight in animals carrying pituitary grafts was 67 +/- 4 per cent, 51 +/- 5 per cent, and 38 +/- 3 per cent of the day 0 value. The difference in the weight of the lateral lobe between the 2 groups was significant on days 7 (p less than 0.001) and 10 (p less than 0.05) and was not significant on day 14. There was no difference in the mean body weight in graft bearing and non-graft bearing animals. Bilateral adrenalectomy at the time of castration did not influence the rate of prostatic regression in either group. Furthermore, pituitaries implanted in rats castrated for 3 weeks had no stimulatory effect of the prostates. These results indicate that increased endogenous prolactin, in the absence of testicular and adrenal secretion, delays the castration-induced regression of the lateral lobe of the prostate of Sprague-Dawley rats.

Adrenal Glands↗
PubMed1982

Activities of cathepsin D in rat prostate during castration induced involution.

The possibility that an intracellular proteolytic process is activated during castration induced prostatic regression warrants consideration and investigation. We investigated the activities of cathepsin D, a lysosomal proteolytic enzyme, in the prostate of rats at different intervals following castration. The enzyme activity was noted to increase during the period of rapid prostatic involution. Administration of exogenous testosterone in varying doses to castrated rats prevented or retarded prostatic weight loss as well as the increase in cathepsin D activity in a dose related manner. Administration of actinomycin D to castrated rats also retarded ventral prostate regression and decreased cathepsin D activity. These observations suggest that cathepsin D is actively synthesized in the regressing prostate and that the enzyme may play an important role in castration induced prostatic regression.

Androgens↗
PubMed1982

Effect of castration on the synthesis of seminal vesicle secretory protein IV in the rat.

The effects of castration on the synthesis (accumulation) of a major seminal vesicle secretory protein (SVS IV) were examined in young adult rats. In vitro incorporation of labeled amino acids into SVS IV by minced tissue was monitored by immunological methods. Castration resulted in a large decrease in the differential synthesis of SVS IV. A significant decrease in the relative incorporation of isotope into SVS IV was evident within 3 days of castration, and by 4 weeks relative incorporation dropped some 30-fold. These changes took place in the presence of a large generalized decline in protein synthesis so that incorporation into SVS IV on an organ basis decreased by over 200-fold. SVS IV messenger RNA levels were estimated by RNA excess solution hybridization using a cloned cDNA probe. Relative message levels declined after castration in harmony with the declines in SVS IV synthesis. SVS IV mRNA was decreased by a relative factor of approximately 20 and an absolute factor of approximately 200 in long-term (40-day) castrates. Accordingly, the seminal vesicle conforms to the general pattern of steroid regulated systems in which hormone withdrawal leads to differential decreases in the steady-state pool size for specific mRNAs. The seminal vesicle is unusual, however, in that a prolonged period is required for maximum differential effects to occur.

Animals↗
PubMed1999

Suppression of 125I-vasoactive intestinal polypeptide binding sites in arteries of the hamster seminal vesicle following castration.

The presence and distribution of 125I-vasoactive intestinal polypeptide (VIP) binding sites in blood vessels supplying the hamster seminal vesicle was studied using a receptor autoradiographic technique before and following castration. 125I-VIP binding was studied in intact animals, in animals under a 15-day period of castration and in animals under the same period of castration but submitted to a further 15-day period of testosterone treatment. Our results show that, in the seminal vesicle, VIP-binding sites are localized in the gland smooth muscle coat and arterial smooth muscle. A 15-day castration period abolishes 125I-VIP binding to vascular smooth muscle but has no effect on 125I-VIP binding to the gland smooth muscle coat. Treatment with testosterone restores 125I-VIP binding to the vascular smooth muscle, completely reversing the effect of castration. Our results indicate that VIP-binding sites in the smooth muscle wall of arteries supplying the hamster seminal vesicle are under androgenic control and are more sensitive to androgen deprivation that VIP-binding sites associated to the gland smooth muscle coat.

Animals↗
PubMed1989

Influence of adult castration on the olfactory sensitivity of the male rat: a signal detection analysis.

The effect of adult castration on the male rat's ability to detect ethyl acetate odor was measured with high-precision olfactometry and a go-no-go signal detection task. Castration was found to significantly mitigate the tendency observed in sham castrates to improve detection performance across an 18-week postoperative test period. No significant castration-related alterations on the responsivity or S+ response latency measures were observed. These findings indicate that castration influences the male rat's ability to improve odor detection performance over time, although it is not known whether this effect is attributable to sensory or to memory mechanisms.

Animals↗
PubMed1970

The effects of increased numbers of carcinogenic treatments on the induction of cervico-vaginal and vulval tumours in intact and castrate rats.

The effect of 5, 10, 20 or 40 weekly local applications of DMBA on the induction of cervico-vaginal epithelial and sarcomatous tumours and on that of squamous celled vulval neoplasms was investigated in intact and castrate rats. The threshold dose increases in the following order: epithelial cervico-vaginal tumours of castrates, followed by those in intacts and by squamous celled vulval tumours and lastly by sarcomas in castrates and intacts.The incidence of sarcomas levels off at about 25% after 20 doses in spayed rats, but increases to 70% with dose in intacts. All sarcomas appear between 200 and 400 days. The incidence of vulval neoplasms increases and the duration of the induction period decreases with dose.Significantly more cervico-vaginal epithelial tumours occur with 5 to 20 paintings than with further application of DMBA. Their peak value is 60% in castrates and 20% in intacts. Castration promotes the progression of vulval papillomas to carcinomas. The sensitivity to carcinogenic stimulation is thus tissue specific and also subject to modification by hormones.While epithelial tumours are multifocal and pass through well-defined intermediate stages (radication, papillomas, microcarcinomas) to full malignancy, the early stages of sarcoma formation are rarely detected and ill-defined. For epitheliomas and sarcomas "invasion" is a criterion of malignancy only if invading cells have acquired "xenoplasia", i.e. the ability to grow in new environments. This capacity increases progressively and its initial lack accounts for the discrepancy between the incidence of embolism and that of metastatic deposits.

Animals↗
PubMed1971

The effect of growth hormone, insulin and alloxan-induced diabetes on carcinogenesis in the genital tract of intact and castrate female rats.

Castrate female rats given weekly applications of DMBA to the genital tract and treated additionally with growth hormone, insulin or alloxan (to induce diabetes) are heavier and have more sarcomatous and epithelial cervico-vaginal neoplasms than intact animals under the same experimental conditions. Promotion of carcinogenesis and gain in body weight are independent phenomena caused by castration in the medicated rats. Growth hormone is most effective in enhancing body weight in all animals, but least as regards tumour formation. It reduces the incidence of sarcomas in intacts, but raises that of epithelial neoplasms, and promotes both types of neoplasms in castrates. The highest incidence of cervico-vaginal epithelial and sarcomatous tumours occurs in spayed diabetics.Squamous celled epitheliomas of the vulva are not affected by castration or additional medication, while basal celled neoplasms tend to be more frequent in intacts than in castrates and particularly numerous in intact failed diabetics. Vulval sarcomas are usually rare but are increased in numbers in diabetic and in insulin treated intacts.Granular myoblastomas of the cervico-vaginal tract occur in intacts only and particularly in diabetics and those medicated with growth hormone or insulin.

Animals↗
PubMed1970

Disappearance of radioactivity from the various ribonucleic acid pools and acid-soluble fractions of mouse liver and kidney after a single injection of labelled orotic acid. The effect of castration.

1. An attempt was made to study the rate of synthesis as well as the distribution of RNA in the various cellular fractions in the livers and kidneys of normal and castrated mice. 2. The tissue was fractionated by the procedure of Blobel & Potter (1967). By using this method it was not possible to find any pronounced difference in the relative proportions of RNA in isolated subcellular fractions when kidneys from normal and castrated mice were compared. On the other hand there was an indication of a shift toward the bound ribosomes in livers from normal mice in comparison with livers from castrated mice. 3. Disappearance of the radioactivity followed the pattern of the first-order reaction. Comparing the half-lives of RNA in liver and kidneys it was found that in the latter in both groups of animals half-lives were shorter no matter which cellular fraction was studied. 4. The half-lives for total homogenate RNA, total ribosomal RNA and low-molecular-weight RNA from kidneys of castrated mice were approximately 20-25% longer than the half-lives for the corresponding fractions from normal mouse kidneys. 5. An explanation is put forward for the anomalous finding that RNA from the castrated-mouse kidneys has a higher specific radioactivity than that isolated from normal mice.

Animals↗