Postpubertal Castration Research Articles

Pubertal Testosterone Programs Adult Behavioral Adaptations to Sexual Experience through Infralimbic Cortex ΔFosB.

Acquisition of social proficiency entails behavioral adaptations to social experience, including both behavioral flexibility and inhibition of behaviors inappropriate in specific social contexts. Here, we investigated the contributions of testosterone and ΔFosB, a transcription factor linked to experience-dependent neural plasticity, to the adolescent maturation of social proficiency in male-female social interactions. To determine whether pubertal testosterone organizes circuits underlying social proficiency, we first compared behavioral adaptations to sexual experience in male Syrian hamsters that were deprived of testosterone during puberty (prepubertal castration; NoT@P) to those of males deprived of testosterone for an equivalent period of time in adulthood (postpubertal castration; T@P). All males were given testosterone replacement in adulthood for two weeks before sexual behavior testing, where males were allowed to interact with a receptive female once per week for five consecutive weeks. T@P males showed the expected decrease in ectopic (mis-directed) mounts with sexual experience, whereas NoT@P males did not. In addition, sexual experience induced FosB gene products expression in the infralimbic cortex (IL) in T@P, but not NoT@P, males. Overexpression of ΔFosB via an adeno-associated viral (AAV) vector in the IL of NoT@P males prior to sexual behavior testing was sufficient to produce a behavioral phenotype similar to that of experienced T@P males. Finally, overexpression of ΔFosB in IL increased the density of immature spines on IL dendrites. Our findings provide evidence that social proficiency acquired through sexual experience is organized by pubertal testosterone through the regulation of ΔFosB in the IL, possibly through increasing synaptic lability.

Male pre- and post-pubertal castration effect on live weight, components of empty body weight, estimated nitrogen excretion and efficiency in Piemontese hypertrofic cattle

To evaluate the effect of sexual neutering and age of castration on empty body weight (EBW) components and estimated nitrogen excretion and efficiency, a trial was carried out on 3 groups of double-muscled Piemontese calves: early castrated (EC, 5th month of age), late castrated (LC, 12th month of age) and intact males (IM, control group). Animals were fed at the same energy and protein level and slaughtered at 18th month of age. Live and slaughtering performances and EBW components were recorded, whereas N excretion was calculated by difference between diet and weight gain N content. In live and slaughtering performances, IM showed higher final, carcass and total meat weight than EC and LC (P<0.01). In EBW components, IM showed higher blood and head weight than EC and LC (P<0.01 and 0.05 respectively), and differences were found between EC and LC for head weights (P<0.01). IM showed higher body crude protein (BCP) than EC and LC (P<0.01 and 0.05 respectively), but BCP/EBW ratio was higher only in IM than EC (P<0.05). Estimated N daily gain was higher in IM than EC and LC (P<0.01). Only LC showed higher excretion than IM (P<0.05), and N efficiency was higher in IM than EC and LC (P<0.05 and 0.01 respectively). In conclusion, for the Piemontese hypertrophied cattle castration significantly increases N excretion (+7%) and reduces N efficiency (−15%), leading to a lower level of sustainability.

Effect of pre- and post-pubertal castration on Piemontese male cattle. II: Carcass measures and meat yield

The effect of different castration ages on carcass morphological characteristics, meat yield, commercial cuts and bones weight and measures was evaluated on Piemontese steers and bulls. Carcasses (24) obtained from early castrated (EC, 5th month of age), late castrated (LC, 13th month) and intact males (IM, control group) of similar age (about 18 months) and fattening degree, were weighed, measured and dissected following the local commercial method. Very few differences were found in carcass conformation and fatness as in carcass weight and measures. After data adjusting, few meat cuts were heavier in IM compared to EC and LC, and only one cut measure was different, whereas, almost no differences were found in bone measures and weight. IM produced carcasses with more edible meat than LC and more forequarter and 2nd quality meat than LC and EC. Significant differences were found also between total, hindquarter and perinephric fat.

Effect of castration age on weight and size of some bones in Piemontese male cattle

Effect of pre- and post-pubertal castration on bone weight and measurements has been studied in 3 groups of Piemontese male cattle (EC - early castrated, LC - late castrated, IM - intact) reared in the same environmental conditions and slaughtered at about 18 month of age, at about 550 kg of l.w., and at the same commercial fattening degree. At side commercial dissection all separated bones were weighted, and on the main ones (scapula, humerus, radius, femur, and tibia) linear measures were recorded and then some conformation ratios were calculated (weight/length, length/width, and length/circumference). Data were analysed by GLM ANCOVA procedure, correcting data on side weight to avoid bias due to differences in carcass weight. No differences were found in side bone weight (23.58 ± 2.61 kg), so as in single bone weight, measures and ratios.

Effect of castration age on weight and size of some muscles in Piemontese male cattle

Effect of pre- and post-pubertal castration on muscle weight and measurements has been studied in 3 groups of Piemontese male cattle (EC - early castrated, LC - late castrated, IM - intact) reared in the same environmental conditions and slaughtered at about 18 month of age, at about 550 kg of l.w., and at the same commercial fattening degree. At side commercial dissection all separated muscles or meat cuts were weighted, and on the most regular ones (regular roll, shoulder clod – “copertina”, blade filet, strip loin, tenderloin, and eye round) linear measures were recorded and then some conformation ratios (weight/length, length/width, and length/circumference) were calculated. Data were analysed by GLM ANCOVA procedure, correcting data on side weight to avoid bias due to differences in carcass weight. Differences were found in meat weight, heavier in IM than in LC and EC (P<0.05), and fat weight, heavier in LC and EC than IM (P<0.01). Only the blade filet weight/length and length/circumference ratios were higher in EC than LC and IM (P<0.05) and in IM than EC (P<0.05) respectively, showing the poor effect of sexual neutralisation on weight and size of the considered muscles.

Effect of pre- and post-pubertal castration on Piemontese male calves: I. Live and slaughtering performances

Abstract To evaluate the effect of different age of castration on live and slaughtering performances in Piemontese males a study was carried out on 24 cattle divided in 3 groups: EC—early castrated (5th month of age), LC—late castrated (13th month) and IM—intact males, reared under the same environmental condition until the same fattening degree, then slaughtered at 18 month of age. The animals were fed at the same energy and protein level. Live weight was recorded monthly and 18 linear body measurements were recorded at 18th month of age. Live performances and slaughtering data were recorded or calculated. Differences were found in live weight (higher in IM than EC and LC; P P P P P

Functional Development of the Rat Urinary Bladder after Pre- or Postpubertal Castration

Experiments were done to evaluate the role of sex hormones in the functional development of the rat urinary bladder. Rats were orchiectomized or ovariectomized at 30 (prepubertal) or 70 (postpubertal) days of age and bladders were removed 1 month later. An additional group of immature male and female rats was used in which the bladders were removed at 30 days of age. There were only minor differences in contractile responses of bladder strips from any group to electrical field stimulation, ATP, carbachol, or KCl compared to age-matched controls. There were no differences in responses of bladder strips from immature females or males to the adrenergic agonists, isoproterenol, norepinephrine, or methoxamine. Bladders from the pre- and postpubertally castrated rats and their controls relaxed fully in response to isoproterenol, but strips from prepubertally castrated rats relaxed significantly less in response to norepinephrine than those from other groups. Approximately one half of the bladder strips from prepubertally castrated rats failed to relax by at least 50% in response to norepinephrine; these same strips responded to methoxamine with exaggerated contractions. Our data indicate that the normal development of rat bladder α-adrenergic responsiveness is adversely altered by prepubertal castration. We postulate that this may result from an alteration in the relative expression of α₁-adrenergic receptor subtypes.

Postnatal maturational changes in rat pelvic autonomic ganglion cells: a mixture of steroid-dependent and -independent effects.

Androgens have potent effects on the maturation and maintenance of a number of neural pathways involved in reproductive behaviors in males. Most studies in this area have focused on central pathways, but androgen receptors are expressed by many peripheral neurons innervating reproductive organs, and previous studies have demonstrated structural and chemical changes in these neurons at puberty and after castration. We have performed the first electrophysiological comparison of pelvic autonomic ganglion neurons in male rats before and after puberty and following pre- or postpubertal castration. Studies were performed in vitro on intact ganglia with hypogastric and pelvic nerves attached to allow synaptic activation of sympathetic or parasympathetic neurons, respectively. Pelvic ganglion neurons underwent many changes in their passive and active membrane properties over the pubertal period, and some of these changes were dependent on exposure to circulating androgens. The most pronounced steroid-dependent effects were on membrane capacitance (soma size) in sympathetic neurons and duration of the action potential afterhyperpolarization in tonic neurons. Our study also showed that rat pelvic ganglion cells and their synaptic inputs were more diverse than previously reported. In conclusion, this study demonstrated that rat pelvic ganglion neurons undergo considerable postnatal changes in their electrophysiological properties. The steroid dependence of some of these changes indicates that circulating androgens may influence reproductive behaviors at many locations within the nervous system not just in the brain and spinal cord.

Maturational and maintenance effects of testosterone on terminal axon density and neuropeptide expression in the rat vas deferens

Testosterone causes growth of many pelvic ganglion cells at puberty and their maintenance during adulthood. Here we have focused on two populations of pelvic ganglion cells that project to the rat vas deferens: noradrenergic neurons that innervate the smooth muscle and synthesize neuropeptide Y, and cholinergic neurons that primarily innervate the mucosa and contain vasoactive intestinal peptide. We have assessed the muscle innervation after pre- or postpubertal castration, using immunohistochemistry to determine axon density and radioimmunoassay to quantify levels of neuropeptides in tissue extracts. Our results show that androgen deprivation in each period causes substantial effects. Noradrenergic axons in the muscle increase in density after castration, partly due to organ size being smaller than age-matched controls. However, when corrected for target size, there is an overall decrease in total number of axons. This implies that androgen exposure at puberty has a direct effect on neurons to ensure that the adult pattern of innervation is attained, and that this is not simply by matching terminal field to target size. Similar effects of pre- and postpubertal castration imply that continued exposure to testosterone is necessary to maintain normal target innervation. Castration in both time periods increased the density of axons containing vasoactive intestinal peptide, however the effects of castration on the total number of these axons in the muscle were more variable. The concentration of vasoactive intestinal peptide increased substantially following either pre- or postpubertal castration although absolute amounts per vas deferens were decreased. Effects on neuropeptide Y concentration were less pronounced but the total amount per vas deferens was decreased after pre- or postpubertal castration. Our study shows that the action of testosterone (or a metabolite) on a pelvic ganglion cell soma is likely to reflect a change in its terminal field, but that these effects are not mediated simply by testosterone influencing the size of its target organ.

Characterization of GH pulsatility in male Shiba goats: effects of postpubertal castration and KP102.

The present study was conducted in order to characterize the secretory pattern of GH in the Shiba goat, a native Japanese miniature goat, and to examine the effects of castration and KP102, a GH secretagogue, on this pattern. Blood samples were taken from an indwelling jugular catheter every 15 min for 24 h, and plasma GH was measured by radioimmunoassay. In intact males, GH was secreted in a pulsatile manner with very regular 5-h periodicity, which consisted of a distinctive GH pulse and a trough of virtually no GH secretion. Postpubertal castration increased the height and decreased the width of GH pulses, though it did not affect the interpulse interval and area under the curve. Modification of the shape of each GH pulse by testicular androgen might play a role in the expression of GH action in the male. KP102 (10 microg/kg, i.v.) immediately induced a robust GH pulse, which was followed by a spontaneous GH pulse of normal characteristics at regular intervals, suggesting that the clock generating GH pulses was reset by KP102. From these observations, we concluded that the Shiba goat is a very suitable experimental model for elucidating the mechanisms underlying GH pulse generation, and in particular, the involvement of androgen and GH secretagogues.

Effect of age of castration, oestradiol treatment and genotype on the fat colour of beef cattle raised at pasture

AbstractIt is hypothesized that the fat colour of steers raised at pasture can be manipulated by altering animal growth patterns using the effects of post-pubertal surgical castration and oestradiol treatment. The fat colour of 151 steers of three genotypes of beef cattle, castrated at approximately 9 months or 18 months of age and treated, or not treated, with oestradiol after castration, was studied.Surgical castration of beef cattle at both 9 months of age or 18 months of age caused no readily apparent animal welfare problems. The combined effects of early or late castration and oestradiol treatment produced varying growth patterns with early castrates exposed to two post-castration episodes of growth associated with carotene-rich forage and late castrates only one such episode of growth.Late castrates and early castrates treated with oestradiol had a less yellow fat than early castrates not treated with oestradiol. The proportion of carcasses with commercially significant yellowness in the fat was decreased by either late castration or by oestradiol treatment. There was no effect of genotype on fat colour.

Testosterone has potent, selective effects on the morphology of pelvic autonomic neurons which control the bladder, lower bowel and internal reproductive organs of the male rat

Although gonadal steroids are important determinants of the development and activity of various neuronal circuits in the brain and spinal cord, their function has been relatively poorly studied in the peripheral nervous system. In the present work, the effects of pre- and postpubertal castration were examined on the morphology of autonomic neurons that supply pelvic visceral organs in male rats. These neurons were identified by peripheral injection of fluorescent retrograde tracers and, in the major pelvic ganglion, were further classified as sympathetic or parasympathetic by means of immunostaining for tyrosine hydroxylase. Sizes of ganglion cell somata were indicated by areas of nucleated profiles in cryosections. The results show that, irrespective of whether castration was carried out at two or seven weeks-of-age, noradrenergic pelvic neurons that supply the vas deferens, prostate gland, urinary bladder or colon achieved only ∼60% of the size of those in unoperated controls. In contrast, cholinergic pelvic neurons were unaffected by castration unless they supplied reproductive targets. Pre- and paravertebral sympathetic neurons that supplied the pelvic viscera were only slightly smaller following castration or were unchanged, depending on their target. All effects of castration were prevented by testosterone replacement following surgery. Androgen receptor-immunoreactivity was particularly prevalent in the nuclei of some pelvic ganglion neurons. The studies suggest that circulating androgens are essential for the maturation and maintenance of the structure of select groups of autonomic neurons that supply the viscera. The presence of androgen receptor immunoreactivity in many of these neurons indicates that direct neuronal effects of androgens are possible. However this does not exclude other less direct mechanisms of steroid action on neurons, such as by an effect on target organs, neurotrophic factor release or peripheral vascular supply. These studies point to the androgenic steroids as potentially important determinants of autonomic reflex function.

Treatment of problem behaviour in dogs and cats by castration and progestagen administration: a review.

Treatment of problem behaviour in companion animals by castration and progestagen administration is reviewed. In male dogs castration is effective in eliminating roaming and, to a lesser extent, mounting, urine marking and intermale aggression. Spraying, roaming and fighting behaviour in cats disappear almost completely after castration. In the latter species prepubertal castration does not seem to be more effective in preventing this problem behaviour than postpubertal castration is in eliminating it. In dogs, intermale aggression, urine marking, mounting and roaming have been treated successfully with progestagens; in cats the same treatment has been successful in decreasing fighting and roaming. There are no reports on the ethical aspects or on adverse side effects of castration. For progestagens a wide range of undesirable side effects have been described. The results of both castration and progestagen therapy differ in the various studies. The underlying mechanism(s) of progestagen influence on behaviour are not understood. Therefore, future research on this topic is necessary.

Hypothalamo-pituitary regulation of cytochrome P-450(15) beta apoprotein levels in rat liver.

The regulation of the sexually differentiated steroid sulfate 15 beta-hydroxylase, cytochrome P-450(15) beta of female rat liver has been investigated. Specific antibodies raised to isozyme P-450(15) beta were used with the Western blot technique to quantitate the specific levels of P-450(15) beta in liver microsomes. The method demonstrated that the levels of the protein are about 16-fold higher in female than in male microsomes and also showed that the specific microsomal content of P-450(15) beta is controlled by GH. Hypophysectomy of female animals resulted in a decrease of P-450(15) beta to male levels. Continuous infusion of human GH, mimicking the female pattern of GH secretion in intact male animals, caused an elevation of the P-450(15) beta level to that of the female. The same dose of human GH in hypophysectomized male or female animals raised the P-450(15) beta level 8-fold or 50% of that seen in normal females. Infusion of ovine PRL to intact male rats had no effect on P-450(15) beta levels, whereas infusion of rat GH caused a 4-fold increase. Thus, the regulation of P-450(15) beta by GH is mainly associated with the somatogenic properties of the hormone. Furthermore, sc injection of rat GH every 12 h, mimicking the male pattern of GH secretion, had no effect on P-450(15) beta levels, demonstrating the importance of the GH secretory pattern in regulation of the specific protein levels. Postpubertal castration of male animals did not influence the microsomal P-450(15) beta content, whereas neonatal castration led to a feminization of the P-450(15) beta content in the adult male rat. Administration of estradiol valerate to male animals caused complete feminization of P-450(15) beta levels, whereas administration of androgen to female animals caused a decrease to male levels. Before 21 days of age, the P-450(15) beta level was slightly higher in male than in female rats. At 35 days, however, the P-450(15) beta level in female rats had increased almost 100-fold, whereas the levels in males increased only slightly. These changes are concomitant with the development of the sexual differentiation of the GH secretory pattern, supporting the role of GH in P-450(15) beta regulation. In conclusion, isozyme P-450(15) beta is a GH-regulated enzyme specific for female rats. The low level of the protein in males is probably explained by neonatal androgenic programming of the GH secretory pattern.

Effect of pre-versus postpubertal castration on aggression between male gerbils

Male gerbils castrated before or after puberty and gonadally intact males and females were tested for agressiveness toward male conspecifics intruding into their living areas. The subjects were exposed to intruders for 10 min or less (if a fight occurred) twice a day for 2 weeks, or until the resident attacked the intruder within 1 min on five of six consecutive tests. Using this paradigm, females and prepubertally castrated males were more aggressive than intact males or males castrated as adults. The different effects of pre- versus postpubertal castration may account for some of the discrepancies in the literature concerning the direction of changes in aggression after castration in this species.

Differentiation of sex steroid-binding protein in adult rhesus monkeys

Several species of primates have sex differences in sex steroid-binding protein (SBP), female adults having higher serum binding capacities (micrograms of dihydrotestosterone bound per deciliter) than male adults, e.g., male humans, 1.28 ± 0.4; human females, 2.86 ± 0.9; Macaca nemestrina male animals, 5.62 ± 1.24; Macaca nemestrina female animals, 11.07 ± 1.85 (means ± standard deviations). SBP correlates inversely with metabolic clearance rates of testosterone (T). The sex difference was identified in rhesus monkeys, six per group, evaluated 4 years after postpubertal castration: male animals 3.95 ± 1.14; female animals 5.85 ± 0.98 (p < 0.05). Estradiol-17β (E2) pellets producing physiologic levels of E2 in female monkeys obliterated the sex difference by increasing SBP in male animals. After withdrawal of E2, physiologic levels of T in male monkeys produced a marked decrease in SBP levels (p < 0.01), and the sex difference reappeared; castrated female animals and prenatally androgenized female animals responded similarly to T (2.81 ± 0.81 and 2.64 ± 0.49, respectively). Both values were greater (p < 0.05) than that of the male group (2.02 ± 0.33). These data suggest that the sex steroid milieu influences the binding capacity of SBP for potent androgens in adulthood but that the differentiation of the SBP sex in rhesus monkeys is determined by factors other than prenatal androgen exposure.

Rat hepatic xanthine oxidase activity: age and sex specific differences.

The effect of maturation, castration, and sex hormonal treatment on hepatic xanthine oxidase activity (XOA) was evaluated in Sprague-Dawley rats. In mature rats XOA was 59% greater in males than in females, whereas in the immature animal the differences between sexes were insignificant. Pubescence resulted in a twofold increase in activity in the male which was prevented by prepubertal orchiectomy. Conversely, prepubertal oophorectomy caused a twofold increase in XOA in females. Urinary uric acid excretion paralleled XOA in rats fed 1% oxonic acid. XOA was significantly elevated in females after postpubertal castration or testosterone treatment while orchiectomy or estradiol-17 beta treatment in the mature male showed no effect. In summary, these data suggest that androgens are required during puberty for full expression of hepatic XOA, and furthermore, an ovarian suppressive effect is evident. In the adult rat only the female responds appreciably to hormonal manipulation.

Le terrier d' Apodemus sylvaticus L.: Sa construction en terrarium et son adaptation a des facteurs externes et internes

In terrarium conditions, burrowing and nest-building activities were found to be regular enough to allow a systematic study. As part of this analysis, a technique for quantification of these activities is described. Qualitative information on burrowing behaviour was obtained with cinematography. • -Several sex differences were observed: females make deeper nests and more complex burrows than males. • -Natural fluctuations of some of the measured activities were found to be linked to the ambient temperature. Low temperature induces an increase in the burrowing, the nest insulation and in the hoarding of food. • -The intensity of illumination during nest building affects nest depth and surface activities. • -The effect of either food deprivation or castration upon nest building was also investigated. While food deprivation increased nest insulation and decreased the burrowing, post-pubertal castration did not alter the observed activities in either sex.

Regulation of the Expression of Autoimmunity in NZB x NZW F1Mice by Sex Hormones

This study examines the role of sex hormones in modulating the expression of autoimmunity in NZB x NZW F1 mice. Male sex hormones were found to retard disease. Differences were noted between prepubertally and postpubertally altered males and females. The presence of male sex hormones prepubertally was associated with marked retardation of the development of antibodies to DNA. Prepubertal but not postpubertal castration of males led to significant acceleration in anti-DNA production. Nevertheless, administration of male sex hormones to females retarded the development of fatal glomerulonephritis, even when given postpubertally. These results suggest that manipulation of sex hormones may be used to modify the expression of autoimmunity.

Neonatal imprinting of enzyme levels in rat adrenals.

ABSTRACT The metabolism of [4-14C]4-androstene-3,17-dione was studied in adrenals from adult male and female rats gonadectomized at birth, at 14 and 43 days of age. A control group consisted of adult male and female rats sham-operated at birth. Another group consisted of adult male and female rats castrated at birth and treated with a single dose of testosterone propionate 24 h after the operation. The 5α-reductase activity was found to be higher in female than in male sham-operated rats (P &lt; 0.02); postpubertal castration led to an increased enzyme activity in both male and female rats. Neonatal testectomy led to higher 5α-reductase activity than testectomy at 14 days of age (P &lt; 0.05) and treatment with testosterone propionate at birth tended to lower the 5α-reductase activity. These results indicate that during the neonatal period testicular androgens irreversibly "imprint" or "programme" the adrenal 5α-reductase activity to a lower, masculine level. Also the 11β-hydroxylase system was found to be subject to androgenic inhibition in two ways: 1. by irreversible "imprinting" or "programming" neonatally and 2. by reversible suppression in adult life. It is concluded that the neonatal masculinization process effectuated by testicular androgens and previously shown to affect hypothalamic functions and liver enzyme levels also affects the activities of steroid metabolizing enzymes in adrenal tissue with possible effects on the adrenal secretion of steroid hormones.