Daily Injections Of Testosterone Propionate Research Articles

Pomegranate Seed Extract: A Strong Antioxidant against Benign Prostatic Hyperplasia Induced Oxidative Stress in Albino Wistar Rats

Aim: The aim of this study was to assess the antioxidant properties of ethanolic and aqueous extracts of Punica granatum (Pomegranate) seed in testosterone induced benign prostate hyperplastic albino Wistar rats.
 Study design: This study is an interventional study.
 Place and Duration of Study: The experimental aspect of this study was conducted at the animal house, Department of Pharmacology, University of Port Harcourt between April and September, 2019.
 Methodology: Seventy (70) adult albino male wistar rats were used for this study. They were divided into 12 groups of 5 rats each and fed with commercial rat diet and clean drinking water. Aqueous and ethanolic extracts of Punica granatum seed were prepared using the maceration method. Benign Prostate Hyperplasia was induced in rats after they submitted to bilateral orchiectomy by daily injections of testosterone propionate (TP) (4 mg/kg b.wt.sc). Rats were treated with 500 or 1500 mg/kg b.wt. of aqueous or ethanoI extracts of Punica granatum seed, dutasteride or in combination. Administration of extracts was done by gavage. Plasma total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase (SOD) activity, were analyzed using sandwich ELISA Kits by Shanghai Korain Biotech Co., Ltd, China, while oxidative stress indices (OSI) were calculated. Statistical analysis was done using SPSS version 22.0 of Windows Stat Pac and p values less than 0.05 were considered statistically significant.
 Results: The results showed that the mean TOS, TAS, SOD and OSI for the rats in the normal control group were 1.66±0.2U/ml, 2.71±0.25U/ml, 41.8±2.9pg/ml and 0.62±0.10 respectively. After BPH induction (group 2), the values were 3.25±0.5U/ml,1.17±0.14U/ml, 23.38±2.09 pg/ml and 2.81±0.60pg/ml respectively. There were significant decreases for TOS and OSI, and significant increases for TAS and SOD when the rats where treated with lower and higher doses of both aqueous and ethanolic extracts of Punica granatum and Dutasteride.
 Conclusion: In conclusion, both doses of Punica granatum seed for ethanolic and aqueous extracts individually and in combination and with dutasteride markedly reduced total oxidant status, oxidative stress indices and improved the activities of antioxidant parameters like superoxide dismutase and total antioxidant status.

Assessment of Antioxidant Effects of Aqueous and Ethanolic Extracts of Zingiber officinale Rhizome in Testosterone Induced Benign Prostatic Hyperplasia Rat Model

Aims: To assess the antioxidant effects of the aqueous and ethanolic extracts of Ginger rhizome in testosterone induced prostate hyperplasic male rats.
 Study Design: The study was a cross-sectional study.
 Place and Duration of Study: The experimental aspect of this study was conducted at the animal house, Department of Pharmacology, University of Port Harcourt between April and September, 2019.
 Methodology: Sixty (60) adult albino male wistar rats were used for this study. They were divided into 12 groups of 5 rats each and fed with commercial rat diet and clean drinking water. Aqueous and ethanolic extractions of Ginger rhizome seed were prepared using the maceration method. BPH was induced in rats after they submitted to bilateral orchiectomy by daily injections of testosterone propionate (TP) (4 mg/kg b.wt.sc). Rats were treated with 500 or 1500 mg/kg b.wt. of aqueous or ethanoI extracts of Zingiber officinale (Zo) rhizome, dutasteride or in combination. Administration of extracts was done by gavage. Plasma total oxidant status (TOS), total antioxidant status (TAS), superoxide dismutase (SOD) activity, were analysed using sandwich ELISA Kits by Shanghai Korain Biotech Co., Ltd, China, while oxidative stress indices (OSI) were calculated. Statistical analysis was done using SPSS version 22.0 of Windows Stat Pac and p values <0.05 were considered statistically significant.
 Results: The results showed that exogenous induction of BPH in rats significantly increased (p=0.000) plasma TOS and OSI while TAS and SOD activities were reduced. However, 500 and 1500 mg/kg b.wt. of Zo rhizome administered orally after exogenous induction of BPH had been established for 15 days, significantly decreased (p=0.000) TOS, OSI and significantly improved the activities of antioxidant parameters like SOD and TAS. Non-significantly increased mean TAS and SOD were seen in a combination of both extracts with dutasteride, possibly suggestive of synergistic interaction between the herbs and the drug. Simultaneous administration of aqueous and ethanolic extracts of Zo rhizome with TP for 30 days also showed antioxidant qualities, although the effects were statistically not better than values for treatments done when BPH was established before treatment. Ethanolic extracts of Zo rhizome produced better antioxidant effects compared to the aqueous extracts.
 Conclusion: From the findings, we conclude that Zo rhizome can ameliorate oxidative stress and therefore may be beneficial in the management of benign prostatic hyperplasia.

Sexual dimorphism of liver endoplasmic reticulum stress susceptibility in prepubertal rats and the effect of sex steroid supplementation.

What is the central question of this study? Is there sexual dimorphism in the occurrence of hepatic endoplasmic reticulum stress? What is the main finding and its importance? The transition from prepubertal to the adult age is associated with an increase in the unfolded protein response markers in the liver of male rats, which is probably due to an increase in serum testosterone levels. Male rodents present a higher predisposition to obesity and insulin resistance than females. These disorders have been associated with endoplasmic reticulum (ER) stress. To investigate a possible sexual dimorphism in the hepatic occurrence of ER stress, we evaluated the expression of ER stress markers in the livers of male and female rats in two phases of sexual development. In the first experimental model, male and female prepubertal and adult Wistar rats were used. Adult males presented higher body mass and greater mass of the adipose tissue and liver than adult females. Prepubertal animals presented no differences in these parameters between males and females. Despite this finding, the hepatic expression levels of Bip, Ire1α and Xbp1s mRNA were lower in prepubertal males than in females, while in adult animals, they did not differ between sexes. In the second experimental model, we anticipated the sexually mature phase by daily injections of testosterone propionate for 10days in prepubertal males or by daily injections of oestradiol benzoate for 7days in prepubertal females. Oestradiol administration in prepubertal females did not change any of the parameters evaluated. Testosterone administration to prepubertal males led to a higher body mass and greater expression of Bip, Ire1α, Atf4 and Xbp1s in the liver. These findings suggest that the increased ER stress predisposition observed in males during puberty is due to an increase in testosterone levels, indicating that ER stress is sexually dimorphic before puberty due to the lack of testosterone in males.

Abstract A007: Methyl jasmonate and finasteride synergistically reduce testosterone-induced benign prostatic hyperplasia through regulation of inflammatory and apoptotic processes in rats

Abstract Background: Phytotherapy is becoming a treatment option in management of diseases, including benign prostatic hyperplasia (BPH). We have shown previously that methyl jasmonate (MeJA) ameliorated BPH; however, the underlying mechanism of action remains unknown. This study was designed to investigate in mechanistic terms the protective role of MeJA in BPH. Methods: BPH was induced by daily injections of testosterone propionate (TP) (3 mg/kg) for 28 days. Results: The weight and organo-somatic weight of prostate in BPH rats were 6.8 and 5.1 times higher than castrated-control group, respectively. Inflammatory markers, prostatic myeloperoxidase,and total nitric oxide were significantly increased in BPH group. The activity of aniline hydroxylase (Phase I drug metabolizing enzyme) was significantly increased in BPH rats by 22%. In BPH group, immunohistochemistry revealed strong expression of prostatic inducible nitric oxide synthase, cyclooxygenase-2 and Bcl2, while mild expression of p53 and Bax WAS seen. Serum triglyceride and total cholesterol were significantly increased, while HDL-c was decreased in BPH. Interestingly, MeJA and finasteride (singly or combination) attenuated inflammatory and apoptotic indices in BPH rats. Conclusion: MeJA and finasteride synergistically protect against TP-induced BPH via mechanisms that involve antiinflammation, induction of apoptosis, and inhibition of phase I drug metabolizing enzyme. Citation Format: Oluwatosin A. Adaramoye, Solomon E. Owumi, Olubukola Akanni, Oluwabunmi E. Olapade-Olaopa, Olusoji J. Abiola, Oluyemi Akinloye. Methyl jasmonate and finasteride synergistically reduce testosterone-induced benign prostatic hyperplasia through regulation of inflammatory and apoptotic processes in rats [abstract]. In: Proceedings of the AACR Special Conference: Prostate Cancer: Advances in Basic, Translational, and Clinical Research; 2017 Dec 2-5; Orlando, Florida. Philadelphia (PA): AACR; Cancer Res 2018;78(16 Suppl):Abstract nr A007.

Methyl jasmonate reduces testosterone-induced benign prostatic hyperplasia through regulation of inflammatory and apoptotic processes in rats

BackgroundPhytotherapy is becoming a treatment option in management of diseases including benign prostatic hyperplasia (BPH). We have shown previously that methyl jasmonate (MeJA) ameliorated BPH, however the underlying mechanism of action remains unknown. This study was designed to investigate in mechanistic terms the protective role of MeJA in BPH. MethodsBPH was induced by daily injections of testosterone propionate (TP) (3mg/kg) for 28 days. ResultsThe weight and organo-somatic weight of prostate in BPH rats were 6.8 and 5.1 times higher than castrated-control group, respectively. Inflammatory markers; prostatic myeloperoxidase and total nitric oxide were significantly increased in BPH group. The activity of aniline hydroxylase (Phase I drug metabolizing enzyme) was significantly increased in BPH rats by 22%. In BPH group, immuno-histochemistry revealed strong expression of prostatic inducible nitric oxide synthase, cyclooxygenase-2 and Bcl2, while mild expression of p53 and Bax were seen. Serum triglyceride and total cholesterol were significantly increased, while HDL-c was decreased in BPH. Interestingly, MeJA and finasteride (singly or combination) attenuated inflammatory indices and induced apoptotic parameters in BPH rats. ConclusionMeJA protects against TP-induced BPH via mechanisms that involve anti-inflammation, induction of apoptosis and inhibition of phase I drug metabolizing enzyme.

Testosterone and social isolation influence adult neurogenesis in the dentate gyrus of male rats

Testosterone has been previously shown to enhance adult neurogenesis within the dentate gyrus of adult male rats, whereas social isolation has been shown to cause a decrease in adult neurogenesis under some conditions. The current study tested the combined effects of testosterone and social isolation upon adult neurogenesis using two experiments involving adult male rats. For both experiments, half of the subjects were pair-housed and half were housed individually for the duration of the experiments (34 days). For experiment 1, the subjects were divided into four groups (n=8/group): (1) sham/pair-housed, (2) sham/isolated, (3) castrate/pair-housed, and (4) castrate/isolated. Rats in the castrate groups were bilaterally castrated, and rats in the sham groups were sham castrated. For experiment 2, all rats were castrated, and the effects of testosterone were tested using daily injections of testosterone propionate (0.500 mg/rat for 15 days) or the oil vehicle. Subjects were divided into four groups (n=8/group): (1) oil/pair-housed, (2) oil/isolated, (3) testosterone/pair-housed, and (4) testosterone/isolated. All rats were injected with 5-bromo-2'-deoxyuridine (BrdU, 200 mg/kg body mass), and immunohistochemistry was used to determine levels of neurogenesis following a 16-day cell survival period. For experiment 1, castrated subjects had significantly fewer BrdU-labeled cells along the granule cell layer and subgranular zone (GCL+SGZ) of the dentate gyrus than did intact subjects, and this effect was mainly due to low levels of neurogenesis in the castrate/isolated group. For experiment 2, social isolation caused a significant decrease in neurogenesis within the GCL+SGZ relative to the pair-housed groups. Testosterone injections did not buffer against this effect but instead tended to cause a decrease in neurogenesis. Thus, social isolation reduced hippocampal neurogenesis, but the effects of testosterone were inconsistent. This suggests that normal circulating levels of testosterone may buffer against the neurogenesis-impairing effects of isolation, whereas high doses of testosterone do not.

Pregnane X Receptor as a Therapeutic Target to Inhibit Androgen Activity

The androgen-androgen receptor signaling pathway plays an important role in the pathogenesis of prostate cancer. Accordingly, androgen deprivation has been the most effective endocrine therapy for hormone-dependent prostate cancer. Here, we report a novel pregnane X receptor (PXR)-mediated and metabolism-based mechanism to reduce androgenic tone. PXR is a nuclear receptor previously known as a xenobiotic receptor regulating the expression of drug metabolizing enzymes and transporters. We showed that genetic (using a PXR transgene) or pharmacological (using a PXR agonist) activation of PXR lowered androgenic activity and inhibited androgen-dependent prostate regeneration in castrated male mice that received daily injections of testosterone propionate by inducing the expression of cytochrome P450 (CYP)3As and hydroxysteroid sulfotransferase (SULT)2A1, which are enzymes important for the metabolic deactivation of androgens. In human prostate cancer cells, treatment with the PXR agonist rifampicin (RIF) inhibited androgen-dependent proliferation of LAPC-4 cells but had little effect on the growth of the androgen-independent isogenic LA99 cells. Down-regulation of PXR or SULT2A1 in LAPC-4 cells by short hairpin RNA or small interfering RNA abolished the RIF effect, indicating that the inhibitory effect of RIF on androgens was PXR and SULT2A1 dependent. In summary, we have uncovered a novel function of PXR in androgen homeostasis. PXR may represent a novel therapeutic target to lower androgen activity and may aid in the treatment and prevention of hormone-dependent prostate cancer.

Later onset of apoptosis in the bulbourethral glands after castration compared to that in the seminal vesicles

Androgens affect many different target organs within the male reproductive tract to stimulate their development and secretory cytodifferentiation, and to maintain structure and function in adulthood. Castration causes regression of these organs via apoptosis. However, not all organs of the reproductive tract are equally sensitive to androgen withdrawal. The effects of castration on the mouse seminal vesicles (SVs) and bulbourethral glands (BUGs) were compared in terms of protein and DNA contents, epithelial apoptosis, and proliferative response of epithelial cells to androgen. Castration induced similar, marked decreases in protein contents in the SV and BUG by 2 days after castration which reached a minimum at 16 days post castration. Both organs underwent a decrease in DNA content, but the kinetics of this decline differed. In the SV, DNA content was significantly decreased by 4 days whereas in the BUG this did not occur until 16 days post castration. By day 16 both organs had regressed to roughly the same degree. The apoptotic index in the epithelium reflected this difference in timing as well. Apoptotic index of the SV epithelium was highest on day 3 after castration and declined thereafter. On the other hand, the apoptotic index in the BUG didn't begin to increase until 7 days after castration and became maximal on day 12. Daily injections of testosterone propionate (TP) from day 8, 16, or 30 after castration all increased epithelial labelling index in the SVs to a similar degree. However, the TP-induced increase in the epithelial labelling index in the BUG beginning on day 8 after castration was considerably less than that in BUGs receiving TP treatment from day 16 or 30 after castration. Thus, the proliferative response of the epithelium depended upon prior apoptosis in the gland, with the timing being delayed in the BUG as compared with the SV. The present results indicate that castration induces epithelial apoptosis and reduction in glandular DNA content considerably later in the BUG than in the SV though reduction in protein content in the BUG fell simultaneously with that in the SV.

Sex difference and steroidal stimulation of galanin immunoreactivity in the ferret's dorsal preoptic area/anterior hypothalamus

A sexually dimorphic male nucleus (MN) is seen in Nissl-stained sections from the dorsal preoptic area/anterior hypothalamus (dPOA/AH) of male, but not female, ferrets. We used immunohistochemical methods to determine whether particular neuropeptides are found in cells of the MN. A sexually dimorphic cluster of galanin-immunoreactive (IR) cells was found in the dPOA/AH of ferrets killed either on embryonic day (E) 38 or in adulthood. Significantly more galanin-IR cells were distributed in the MN and in other subregions of the dPOA/AH of intact breeding males than estrous females. The density of galanin-IR cells in the dPOA/AH was significantly reduced in adult males by castration and restored to the level of intact breeding males by daily injections of testosterone propionate (TP) for 5 weeks. The same TP treatment failed to augment the density of galanin-IR cells in the dPOA/AH of adult, ovariectomized females. Computer-assisted image analysis and grid-crossing analysis showed that the area and the number of galanin-IR fibers in the dPOA/AH were significantly greater in adult females than in males, regardless of subjects' concurrent steroidal condition. A cluster of galanin-IR cells was present in the dPOA/AH of males, but not females, killed on either E34 or E38. Administration of TP between E28 and E37 significantly increased the density of galanin-IR cells in the dPOA/AH of females killed on E38, up to the level seen in control males. The results suggest that the capacity of cells located in the dPOA/AH to express galanin after adult steroid exposure is sexually differentiated by the fetal action of testosterone, or its metabolite, estradiol, in males. J. Comp. Neurol. 389:277–288, 1997. © 1997 Wiley-Liss, Inc.

Sex difference and steroidal stimulation of galanin immunoreactivity in the ferret's dorsal preoptic area/anterior hypothalamus

A sexually dimorphic male nucleus (MN) is seen in Nissl-stained sections from the dorsal preoptic area/anterior hypothalamus (dPOA/AH) of male, but not female, ferrets. We used immunohistochemical methods to determine whether particular neuropeptides are found in cells of the MN. A sexually dimorphic cluster of galanin-immunoreactive (IR) cells was found in the dPOA/AH of ferrets killed either on embryonic day (E) 38 or in adulthood. Significantly more galanin-IR cells were distributed in the MN and in other subregions of the dPOA/AH of intact breeding males than estrous females. The density of galanin-IR cells in the dPOA/AH was significantly reduced in adult males by castration and restored to the level of intact breeding males by daily injections of testosterone propionate (TP) for 5 weeks. The same TP treatment failed to augment the density of galanin-IR cells in the dPOA/AH of adult, ovariectomized females. Computer-assisted image analysis and grid-crossing analysis showed that the area and the number of galanin-IR fibers in the dPOA/AH were significantly greater in adult females than in males, regardless of subjects' concurrent steroidal condition. A cluster of galanin-IR cells was present in the dPOA/AH of males, but not females, killed on either E34 or E38. Administration of TP between E28 and E37 significantly increased the density of galanin-IR cells in the dPOA/AH of females killed on E38, up to the level seen in control males. The results suggest that the capacity of cells located in the dPOA/AH to express galanin after adult steroid exposure is sexually differentiated by the fetal action of testosterone, or its metabolite, estradiol, in males.

Long-Term Effects of Androgen Treatment on Fear Reactions in Ewes

We have previously demonstrated that testosterone treatment reduces fear reactions of ewes subjected to daily injections of testosterone propionate (10 mg/day) for 56 days. The long-term effects of this treatment were studied in the same ewes and using the same battery of fear-eliciting tests (isolation from conspecifics, surprise, and presence of a human) 4 and 8 months after the injections were terminated. Twenty-six behavioral items related to fear were recorded. A number of differences in the behavior of treated vs control animals indicate that the former are still less fearful, especially in the surprise and human tests. Overall fearfulness scores of treated and control ewes (the higher the score, the more fearful the animals) were 7.3 ± 1.7 vs 9.7 ± 1.9, (P< 0.05) for the surprise test, and 7.0 ± 1.4 vs 10.0 ± 2.0 (P< 0.01) for the human test at 4 months, and 6.8 ± 1.4 vs 8.2 ± 1.1 (P< 0.05) for the human test at 8 months. Thus, not only does testosterone treatment reduce fear reactions in ewes but it also has a long lasting effect on such reactions.

Expression of estrogen receptor in the facial nucleus is suppressed by estradiol, but not by testosterone, indicating a lack of requirement for aromatization

The transient expression of estrogen receptor (ER) in the ventromedial subnucleus of the facial nucleus was previously detected in the newborn rat, and the expression of ER molecules was down-regulated by daily injections of estradiol. Here we examined possible involvement of aromatization in this process. ER molecules were measured by immunohistochemistry and in situ hybridization histochemistry after daily injections of testosterone propionate (TP;100 μg/0.02 ml) and estradiol benzoate (EB; 10 μg/0.02 ml) in the male pups castrated within 24 h of birth. Daily injections of TP for 5 consecutive days did not suppress ER and ER mRNA in the facial nucleus, while they were both suppressed by daily injections of EB. Moreover, aromatase immunoreactivity was not detected in the facial nucleus of both castrated, TP injected and intact control males at 6 days of age. The present findings therefore suggest that ER molecules expressed transiently in the facial nucleus are not directly involved in masculine sexual differentiation of the brain in newborn rat.

Effects of 4‐MAPC, a 5α‐reductase inhibitor, and cyproterone acetate on regrowth of the rat ventral prostate

Inhibitors of 5 alpha-reductase activity cause less involution of the rat ventral prostate (VP) than does castration. Studies were conducted in adult Sprague Dawley rats to evaluate the effects of a potent 5 alpha-reductase inhibitor, 4-MAPC, and the antiandrogen, cyproterone acetate (CA), on DNA synthesis and apoptosis. In experiment 1, VP weight fell 33%, 53%, and 83%, and DNA per ventral prostate was reduced 24%, 46%, and 71%, by 4-MAPC, CA, and castration, respectively. In experiment 2, adult rats were castrated, and the VP involuted for 7 days prior to 3 daily injections of testosterone propionate (TP; 1 mg/kg/d) +/- 10 mg/kg/d of 4-MAPC or CA. 3H-thymidine incorporation into VP DNA was increased in castrated animals treated with TP, and 4-MAPC and CA reduced uptake. In experiment 3, animals were treated for 14 days with the same protocol as that used in experiment 2. VP weight was increased in all animals treated with TP when compared with castration, and was reduced by both 4-MAPC and CA. DNA in rats treated with TP was similar to that in intact animals. DNA was not reduced by 4-MAPC, but was reduced by CA. The mRNA for TRPM-2, a marker of apoptosis, was increased only in untreated castrated rats. It appears that CA has a greater inhibitory effect than 4-MAPC on DNA synthesis. A major reason why castration reduces DNA more than either 4-MAPC or CA is that neither of these agents was able to increase programmed cell death to the degree seen with castration.

Dihydrotestosterone-sensitive neurons in the male rat ventromedial hypothalamus

Electrical stimulation of the midbrain central gray caused antidromic activation in 273 neurons in and around the hypothalamic ventromedial nucleus in 40 urethan-anesthetized male rats. The latency (range: 2–39 ms) and threshold (100–1,600 μA) of the responses were compared among intact males and orchidectomized males, which received either no treatment, daily injections of testosterone propionate or dihydrotestosterone, or a combined estradiol benzoate and progesterone injection. Recordings were from comparable neuronal pools, because probability distribution for the latency as well as histological localization of each response were not different among groups. Orchidectomy decreased the mean threshold, and either treatment reversed the effect. Dihydrotestosterone increased the mean threshold by reducing the number of cells with thresholds below 600 μA, to a level as in intact males. Estrogen reduced the number of cells responding at 300–900 μA, but at lower thresholds, fell short of replicating the distribution in intact males. Testosterone reinstated the distribution as in intact males. It was concluded that different subgroups of ventromedial hypothalamic neurons with specific sensitivity to metabolites of testosterone project to the central gray.

Divergent Regulation of Gonadotropin Subunit mRNA Levels by Androgens in the Female Rat1

To examine the effects of gonadal steroids on the pretranslational regulation of the gonadotropin subunits in the female, adult female rats, beginning 7 or 28 days after ovariectomy, received daily injections of testosterone propionate (T), dihydrotestosterone propionate (D), or estradiol benzoate (E) for 7 days. Intact cycling females and ovariectomized rats that received vehicle served as controls. Serum was obtained for LH and FSH levels to assess changes in gonadotropin secretion. Total RNA from individual rats was recovered and analyzed by blot hybridization with specific radiolabeled cDNA probes for the alpha, LH beta, and FSH beta subunits. Autoradiographic bands were quantitated and standardized to mRNA levels in the intact animals. Ovariectomy resulted in a rise in serum gonadotropin levels and all three gonadotropin subunit mRNA levels. Estrogen replacement resulted in suppression of alpha, LH beta, and FSH beta mRNAs whether given at 7 or 28 days after ovariectomy. In contrast, whereas androgen replacement decreased alpha and LH beta mRNAs, D or T did not consistently suppress FSH beta mRNAs. We conclude that chronic estrogen administration to the castrated female rat uniformly suppresses all three gonadotropin subunit mRNA levels. In female rats, as in male rats, chronic androgen administration fails to negatively regulate FSH beta mRNAs.

Androgen regulation of dendritic growth and retraction in the development of a sexually dimorphic spinal nucleus

The spinal nucleus of the bulbocavernosus (SNB) is a sexually dimorphic group of motoneurons whose development and maintenance are under androgenic control. Exposure to androgens early in development permanently alters SNB motoneuron number and soma size; in adulthood, androgens regulate dendritic and synaptic architecture. The present set of experiments investigates the influence of androgens on the development of SNB dendritic morphology. In normal males, SNB dendritic growth is biphasic, reaching exuberant lengths by the fourth postnatal week and then retracting to adult lengths by 7 weeks of age. This dendritic growth is androgen dependent--males castrated on postnatal day (P) 7 and given daily injections of testosterone propionate (TP) had exuberant dendritic lengths similar to those of normal males; dendritic length in oil-treated males remained at P7 levels. The early exuberant dendritic length was retained in TP-treated males through P49. The retraction of SNB dendrites after P28 is also influenced by androgens. Males castrated at P28 and given testosterone implants retained exuberant dendritic length at P49; blank-implanted males had significantly shorter dendritic lengths by P70. These results suggest that androgens are necessary for the early exuberant growth of SNB dendrites. Furthermore, the subsequent retraction of SNB dendrites may be halted when testosterone titers reach a critical level during puberty, stabilizing their adult length.

Effects of testosterone propionate upon habit-reversals and one-trial learning by castrated white rats.

32 male white rats, littermates from mothers of same strain, started to learn 20 habit-reversal problems at 50 days of age in an E-maze for water by the noncorrectional method. They were divided into 3 groups. Two groups of 11 each had been castrated at 32 days of age, and a group of 10 served as control. One castrated group received daily injections of testosterone propionate at 1 mg per kg of body weight 11 days after surgery. The other castrated group and the normal controls received saline. A week of preliminary training accustomed the animals to the daily routine of injection, about 30 min. before being put in the drinking box of a straight alley which they ran for water during the last 2 days. In maze learning proper, after a rat made 9 correct choices on 10 daily trials, the goal was reversed for the next problem. Early in learning, there were some fluctuations in performance, but throughout the rest of the experiment, the castrated-saline group was consistently and significantly inferior to the normals, testifying to the detrimental effect of castration upon adaptive ability in learning successive reversal problems. The fact that the castrated-testosterone group was far superior to the castrated-saline group and exhibited no significant difference from the normal-saline group shows unequivocally that testosterone propionate has a therapeutic property of raising the learning ability of the retarded, castrated white rats to a normal level. A theory is suggested.

Proliferative response of seminal vesicle cells to androgen in mice castrated neonatally and pretreated with estrogen or androgen at adulthood.

Seminal vesicle cells of neonatally castrated adult mice show poor response to androgen, compared to those of mice castrated at adulthood; effects of pretreatment with androgen or estrogen at adulthood on androgen-induced proliferation of the seminal vesicle cells were examined in neonatally castrated mice. Male mice castrated at day 0 after birth were pretreated with daily injections of testosterone propionate (TP, 100 micrograms/mouse), 17 beta-estradiol (E2, 5 micrograms/mouse) or vehicle for 20 days starting from day 60; daily TP injections (100 micrograms/mouse) for 30 days were started again from day 110 in all the pretreated mice to examine androgen-induced proliferation by incorporation of 5-[125I]iodo-2'-deoxyuridine into the whole seminal vesicles. Both TP and E2 pretreatments significantly increased the seminal vesicle weight found before TP treatment. However, androgen-induced proliferation of the seminal vesicle found in neonatally castrated mice (poor response; long duration with a low peak on day 3) was changed at least in part to that found in mice castrated at adulthood (good response; short duration with a high peak on day 3) only following the TP pretreatment but not at all following the E2 pretreatment. The E2 pretreatment induced poor androgen-induced proliferation with a low peak on day 7.

Roles of neonatal and prepubertal testicular androgens on androgen-induced proliferative response of seminal vesicle cells in adult mice

Male mice were castrated at 0, 10, 20, 30, 40 and 60 days of age; daily injections of testosterone propionate (TP, 4 μg/g b. wt) were started from day 90. On various days after starting the TP injections, the incorporation of 5-[ 125I]iodo-2′-deoxyuridine into the whole seminal vesicles was determined as an index for proliferation. The seminal vesicle cells in mice castrated on days 0 and 20 were characterized by low weight (0.5–1 mg) before TP injection, long duration of androgen-induced proliferation (> 20 days) with a low peak, and involvement of both epithelial and fibromuscular cells (neonatal castration type). The seminal vesicle cells in mice castrated on days 60 and 40 were characterized by relatively high weight (5–10 mg) before TP injection, short duration of androgen-induced poroliferation (10 days) with a high peak, and involvement of only the epithelial cells (adult castration type). In mice castrated on days 0 and 20, the neonatal castration type of androgen-induced proliferation was completely changed to the adult castration type when TP pretreatment (2 μg/g b. wt per 12 h) had been given from day 20 to day 40. However, the TP pretreatment given from day 90 to day 110 instead of days 20–40 had no such effect in 140-day old mice castrated on day 0. The present findings suggest that testicular androgens secreted from day 20 to day 40 play an indispensable role in the induction of irreversible proliferative response of the mouse seminal vesicle. The activity of the prepubertal androgens may not be completely compensated by androgen activity at adulthood.

Effect of long term androgen removal on androgen-induced proliferation of seminal vesicle cells in adult mice

Male mice were castrated on day 60 after birth; daily injections of testosterone propionate (TP, 4μg/g b.wt) were started 1,2 or 6 months after the castration. The incorporation of 5-[ 125I]iodo-2'-deoxyuridine ([ 125I]IdUrd) into the whole seminal vesicles was determined on various days after starting the TP injections as an index for proliferation. Although the peak of [ 125I]IdUrd uptake was observed 3 days after starting the TP injections in both short (1–2 months) and long (6 months) term castrated mice, the peak was significantly lower and the period of proliferation was longer in the long term group than in the short term group; the weights of seminal vesicles before TP injections were 6 and 10 mg in the long and short term groups, respectively. Although TP injections induced the proliferation of only epithelial cells in the short term group, the same treatment induced the proliferation of both epithelial and fibromuscular cells in the long term group. The deficient responsiveness to androgen of the seminal vesicle cells found in the long term castrated mice was completely recovered by TP pretreatment for 2 weeks. The present findings suggest that so-called imprinted cells in the mouse seminal vesicle induced by neonatal and prepubertal testicular androgens are very slowly lost at least in part by androgen removal for long periods such as more than 6 months in adult mice and that the loss is at least in part due to the death of fibromuscular cells, which is recovered rather quickly by androgen pretreatment.