1
|
Han X, Zhou Y, Zeng Y, Sui F, Liu Y, Tan Y, Cao X, Du X, Meng F, Zeng X. Effects of active immunization against GnRH versus surgical castration on hypothalamic-pituitary function in boars. Theriogenology 2017; 97:89-97. [PMID: 28583614 DOI: 10.1016/j.theriogenology.2017.04.038] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/21/2016] [Revised: 04/24/2017] [Accepted: 04/24/2017] [Indexed: 11/17/2022]
Abstract
The objective was to compare effects of anti-GnRH immunization (immunocastration) versus surgical castration on hypothalamic-pituitary function in boars. Thirty-six boars were randomly divided into three groups (n = 12/group): control, surgically castrated, or immunized against GnRH at 10 wk of age (boostered 8 wk later). Compared to intact boars, immunocastration reduced (P < 0.05) serum concentrations of LH, FSH, testosterone and inhibin B and caused severe testicular atrophy, whereas surgical castration increased (P < 0.05) serum concentrations of LH and FSH. Both immunocastration and surgical castration consistently reduced hypothalamic GnRH synthesis, with decreased (P < 0.05) mRNA expressions of GnRH, GnRH up-stream gatekeeper genes kiss1 and its receptor (GPR54), and androgen receptor in the hypothalamic arcuate nucleus (ARC) and anteroventral periventricular nucleus (AVPV), as well as GnRH content in the median eminence. Inconsistently, mRNA expressions of gonadotropin-inhibitory hormone (GnIH) in ARC and AVPV as well as its receptor (GPR147) in pituitary were selectively reduced (P < 0.05), but mRNA expressions of estrogen receptor alpha and aromatase (CPY17A1) in pituitary were selectively increased (P < 0.05) in surgical castrates. In response to selectively attenuated suppressive signaling from GnIH and testosterone, mRNA expressions of GnRH receptor (GnRHR), LH-β and FSH-β in pituitary were increased (P < 0.05) in surgical castrates, whereas these pituitary gene expressions were decreased (P < 0.05) in immunocastrates, due to loss of hypothalamic GnRH signaling. We concluded that immunocastration and surgical castration consistently reduced hypothalamic GnRH synthesis due to a testosterone deficiency disrupting testosterone-Kisspeptin-GPR54-GnRH signaling pathways. Furthermore, selectively attenuated GnIH and testosterone signaling in the pituitary increased gonadotropin production in surgical castrates.
Collapse
Affiliation(s)
- Xingfa Han
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Yuqin Zhou
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Yu Zeng
- College of Animal Science, Sichuan Agricultural University, Chengdu Campus, Chengdu, Sichuan, 611130, PR China
| | - Fenfen Sui
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Yacheng Liu
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Yao Tan
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Xiaohan Cao
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Xiaogang Du
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Fengyan Meng
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China
| | - Xianyin Zeng
- Isotope Research Lab, Biological Engineering and Application Biology Department, Sichuan Agricultural University, Ya'an, 625014, PR China.
| |
Collapse
|
2
|
Filippa VP, Rosales GJ, Cruceño AAM, Mohamed FH. Androgen Receptors Expression in Pituitary of Male Viscacha in relation to Growth and Reproductive Cycle. Int J Endocrinol 2015; 2015:168047. [PMID: 25945090 PMCID: PMC4405020 DOI: 10.1155/2015/168047] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 11/26/2014] [Revised: 03/06/2015] [Accepted: 03/08/2015] [Indexed: 11/18/2022] Open
Abstract
The aim of this work was to study the androgen receptors (AR) expression in pituitary pars distalis (PD) of male viscachas in relation to growth and reproductive cycle. AR were detected by immunocytochemistry and quantified by image analysis. Pituitary glands from fetus, immature, prepubertal, and adult viscachas during their reproductive cycle were used. In the fetal PD, the immunoreactivity (ir) was mainly cytoplasmic. In immature and prepubertal animals, AR-ir was cytoplasmic (ARc-ir) and nuclear (ARn-ir) in medial region. In adult animals, ARn-ir cells were numerous at caudal end. AR regionalization varied between the PD zones in relation to growth. In immature animals, the ARn-ir increased whereas the cytoplasmic expression decreased in relation to the fetal glands. The percentage of ARc-ir cells increased in prepubertal animals whereas the nuclear AR expression was predominant in adult viscachas. The AR expression changed in adults, showing minimum percentage in the gonadal regression period. The variation of nuclear AR expression was directly related with testosterone concentration. These results demonstrated variations in the immunostaining pattern, regionalization, and number of AR-ir cells throughout development, growth, and reproductive cycle, suggesting the involvement of AR in the regulation of the pituitary activity of male viscacha.
Collapse
Affiliation(s)
- Verónica Palmira Filippa
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, Bloque I, Piso No. 1, 5700 San Luis, Argentina
- Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET), 5700 San Luis, Argentina
| | - Gabriela Judith Rosales
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, Bloque I, Piso No. 1, 5700 San Luis, Argentina
| | - Albana Andrea Marina Cruceño
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, Bloque I, Piso No. 1, 5700 San Luis, Argentina
| | - Fabian Heber Mohamed
- Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Avenida Ejército de los Andes 950, Bloque I, Piso No. 1, 5700 San Luis, Argentina
- *Fabian Heber Mohamed:
| |
Collapse
|
3
|
Filippa V, Godoy D, Perez E, Mohamed F. Effects of castration on androgen receptors and gonadotropins in the pituitary of adult male viscachas. Reprod Fertil Dev 2013; 26:991-1000. [PMID: 23905557 DOI: 10.1071/rd13126] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/24/2013] [Accepted: 06/26/2013] [Indexed: 11/23/2022] Open
Abstract
The aims of the present study were to determine whether castration results in quantitative immunohistochemical changes in androgen receptors (AR), LH-immunoreactive (IR) cells and FSH-IR cells, and to analyse the colocalisation of AR and gonadotropins in the pituitary pars distalis (PD) of viscachas. Pituitaries were processed for light and electron microscopy. AR-IR, LH-IR and FSH-IR cells were detected by immunohistochemistry. In morphometric studies, the percentage of AR-IR, LH-IR, FSH-IR, LH-IR/AR-IR and FSH-IR/AR-IR cells was determined. In intact viscachas, AR were distributed throughout the PD; they were numerous at the caudal end, with intense immunostaining. LH-IR cells and FSH-IR cells were found mainly in the ventral region and at the rostral end of the PD. Approximately 45%-66% of LH-IR cells and 49%-57% of FSH-IR cells expressed AR in the different zones of the PD. In castrated viscachas, there was a significant decrease in the percentage of AR-IR, LH-IR, FSH-IR, and FSH-IR/AR-IR cells. Some pituitary cells from castrated viscachas also exhibited ultrastructural changes. These results provide morphological evidence that gonadal androgens are directly related to the immunolabelling of AR, LH and FSH. Moreover, the colocalisation of AR and FSH is most affected by castration, suggesting the existence of a subpopulation of gonadotrophs with different regulatory mechanisms for hormonal synthesis, storage and secretion.
Collapse
Affiliation(s)
- Verónica Filippa
- Laboratorio de Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950- Bloque I, 1° Piso (5700) San Luis, Argentina
| | - Daiana Godoy
- Laboratorio de Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950- Bloque I, 1° Piso (5700) San Luis, Argentina
| | - Edith Perez
- Laboratorio de Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950- Bloque I, 1° Piso (5700) San Luis, Argentina
| | - Fabian Mohamed
- Laboratorio de Histología, Facultad de Química, Bioquímica y Farmacia, Universidad Nacional de San Luis, Av. Ejército de los Andes 950- Bloque I, 1° Piso (5700) San Luis, Argentina
| |
Collapse
|
4
|
Tang H, Vasselli JR, Tong C, Heymsfield SB, Wu EX. In vivo MRI evaluation of anabolic steroid precursor growth effects in a guinea pig model. Steroids 2009; 74:684-93. [PMID: 19463691 PMCID: PMC4393994 DOI: 10.1016/j.steroids.2009.02.012] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/20/2009] [Revised: 02/19/2009] [Accepted: 02/28/2009] [Indexed: 10/21/2022]
Abstract
Anabolic steroids are widely used to increase skeletal muscle (SM) mass and improve physical performance. Some dietary supplements also include potent steroid precursors or active steroid analogs such as nandrolone. Our previous study reported the anabolic steroid effects on SM in a castrated guinea pig model with SM measured using a highly quantitative magnetic resonance imaging (MRI) protocol. The aim of the current study was to apply this animal model and in vivo MRI protocol to evaluate the growth effects of four widely used over-the-counter testosterone and nandrolone precursors: 4-androstene-3 17-dione (androstenedione), 4-androstene-3beta 17beta-diol (4-androsdiol), 19-nor-4-androstene-3beta-17beta-diol (bolandiol) and 19-nor-4-androstene-3 17-dione (19-norandrostenedione). The results showed that providing precursor to castrated male guinea pigs led to plasma steroid levels sufficient to maintain normal SM growth. The anabolic growth effects of these specific precursors on individual and total muscle volumes, sexual organs, and total adipose tissue over a 10-week treatment period, in comparison with those in the respective positive control testosterone and nandrolone groups, were documented quantitatively by MRI.
Collapse
Affiliation(s)
- Haiying Tang
- Department of Radiology, Columbia University, New York, NY 10032, USA
- Merck Research Laboratories, Merck & Co Inc., Rahway, NJ 07065, USA
| | - Joseph R. Vasselli
- Obesity Research Center, St. Luke’s-Roosevelt Hospital, Columbia University, New York, NY 10025, USA
| | - Christopher Tong
- Merck Research Laboratories, Merck & Co Inc., Rahway, NJ 07065, USA
| | - Steven B. Heymsfield
- Merck Research Laboratories, Merck & Co Inc., Rahway, NJ 07065, USA
- Obesity Research Center, St. Luke’s-Roosevelt Hospital, Columbia University, New York, NY 10025, USA
| | - Ed X. Wu
- Department of Radiology, Columbia University, New York, NY 10032, USA
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, PR China
- Corresponding author at: Laboratory of Biomedical Imaging and Signal Processing, Departments of Electrical & Electronic Engineering, Medicine and Anatomy, The University of Hong Kong, Hong Kong SAR, PR China. Tel.: +852 2859 7096; fax: +852 2559 8738. (E.X. Wu)
| |
Collapse
|
5
|
Holmes MM, Goldman BD, Forger NG. Social status and sex independently influence androgen receptor expression in the eusocial naked mole-rat brain. Horm Behav 2008; 54:278-85. [PMID: 18455726 PMCID: PMC2630401 DOI: 10.1016/j.yhbeh.2008.03.010] [Citation(s) in RCA: 36] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 01/24/2008] [Revised: 03/12/2008] [Accepted: 03/14/2008] [Indexed: 10/22/2022]
Abstract
Naked mole-rats (Heterocephalus glaber) are eusocial rodents that live in large subterranean colonies including a single breeding female and 1-3 breeding males; all other members of the colony, known as subordinates, are reproductively suppressed. We recently found that naked mole-rats lack many of the sex differences in the brain and spinal cord commonly found in other rodents. Instead, neural morphology is influenced by breeding status, such that breeders, regardless of sex, have more neurons than subordinates in the ventromedial nucleus of the hypothalamus (VMH), and larger overall volumes of the bed nucleus of the stria terminalis (BST), paraventricular nucleus (PVN) and medial amygdala (MeA). To begin to understand how breeding status influences brain morphology, we examined the distribution of androgen receptor (AR) immunoreactivity in gonadally intact breeders and subordinates of both sexes. All animals had AR+ nuclei in many of the same regions positive for AR in other mammals, including the VMH, BST, PVN, MeA, and the ventral portion of the premammillary nucleus (PMv). We also observed diffuse labeling throughout the preoptic area, demonstrating that distribution of the AR protein in presumptive reproductive brain nuclei is well-conserved, even in a species that exhibits remarkably little sexual dimorphism. In contrast to other rodents, however, naked mole-rats lacked AR+ nuclei in the suprachiasmatic nucleus and hippocampus. Males had more AR+ nuclei in the MeA, VMH, and PMv than did females. Surprisingly, breeders had significantly fewer AR+ nuclei than subordinates in all brain regions examined (VMH, BST, PVN, MeA, and PMv). Thus, social status is strongly correlated with AR immunoreactivity in this eusocial species.
Collapse
Affiliation(s)
- Melissa M Holmes
- Center for Neuroendocrine Studies and Department of Psychology, University of Massachusetts, Amherst, MA 01003, USA.
| | | | | |
Collapse
|
6
|
Wu EX, Tang H, Tong C, Heymsfield SB, Vasselli JR. In vivo MRI quantification of individual muscle and organ volumes for assessment of anabolic steroid growth effects. Steroids 2008; 73:430-40. [PMID: 18241900 PMCID: PMC4393993 DOI: 10.1016/j.steroids.2007.12.011] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/29/2007] [Revised: 12/10/2007] [Accepted: 12/11/2007] [Indexed: 10/22/2022]
Abstract
This study aimed to develop a quantitative and in vivo magnetic resonance imaging (MRI) approach to investigate the muscle growth effects of anabolic steroids. A protocol of MRI acquisition on a standard clinical 1.5 T scanner and quantitative image analysis was established and employed to measure the individual muscle and organ volumes in the intact and castrated guinea pigs undergoing a 16-week treatment protocol by two well-documented anabolic steroids, testosterone and nandrolone, via implanted silastic capsules. High correlations between the in vivo MRI and postmortem dissection measurements were observed for shoulder muscle complex (R=0.86), masseter (R=0.79), temporalis (R=0.95), neck muscle complex (R=0.58), prostate gland and seminal vesicles (R=0.98), and testis (R=0.96). Furthermore, the longitudinal MRI measurements yielded adequate sensitivity to detect the restoration of growth to or towards normal in castrated guinea pigs by replacing circulating steroid levels to physiological or slightly higher levels, as expected. These results demonstrated that quantitative MRI using a standard clinical scanner provides accurate and sensitive measurement of individual muscles and organs, and this in vivo MRI protocol in conjunction with the castrated guinea pig model constitutes an effective platform to investigate the longitudinal and cross-sectional growth effects of other potential anabolic steroids. The quantitative MRI protocol developed can also be readily adapted for human studies on most clinical MRI scanner to investigate the anabolic steroid growth effects, or monitor the changes in individual muscle and organ volume and geometry following injury, strength training, neuromuscular disorders, and pharmacological or surgical interventions.
Collapse
Affiliation(s)
- Ed X Wu
- Laboratory of Biomedical Imaging and Signal Processing, The University of Hong Kong, Hong Kong SAR, China.
| | | | | | | | | |
Collapse
|
7
|
Jacobs C, Van Den Broeck W, Simoens P. Increased Number of Neurons Expressing Androgen Receptor in the Basolateral Amygdala of Pathologically Aggressive Dogs. ACTA ACUST UNITED AC 2006; 53:334-9. [PMID: 16922829 DOI: 10.1111/j.1439-0442.2006.00840.x] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/30/2022]
Abstract
The present study aimed to determine the extent to which the androgen receptor (AR) is directly involved in the hormonal modulation of pathological canine aggressive behaviour in the basolateral nuclear group (BNG) of the amygdaloid body. A stereological quantification of AR-positive neurons was performed in the BNGs of normally behaving and aggressive male dogs. The BNG was selected because it is involved in sexual and behavioural activities that are influenced by androgens. In the aggressive dogs the BNG contained a significantly higher number of AR-positive neurons compared with normally behaving dogs suggesting differences in androgen activity within the BNGs of both the groups. However, additional mechanisms are likely to be involved because the AR-negative fraction of BNG neurons was also increased in the aggressive dogs. It was concluded that most of the AR was unliganded because a cytoplasmic staining pattern of AR positivity was observed in the canine BNG neurons. This indicates that genomic androgen actions, which are mediated through the AR are of minor importance in the testosterone modulation of canine aggression within the BNG. Other non-genomic mechanisms through which androgens may exert their action in the BNG are discussed. The aromatase pathway is suggested to be the main mechanism through which testosterone exerts its action within the BNG.
Collapse
Affiliation(s)
- C Jacobs
- University of Antwerp, Universiteitsplein 1, 2610 Wilrijk, Belgium.
| | | | | |
Collapse
|
8
|
Belle MD, Lea RW. Androgen receptor immunolocalization in brains of courting and brooding male and female ring doves (Streptopelia risoria). Gen Comp Endocrinol 2001; 124:173-87. [PMID: 11703083 DOI: 10.1006/gcen.2001.7693] [Citation(s) in RCA: 29] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/22/2022]
Abstract
Nuclear androgen receptors (ARs) were localized immunocytochemically in the brains of courting and brooding male and female ring doves (Streptopelia risoria). AR immunoreactivity (AR-ir) in courting birds was localized in cell nuclei in the telencephalon, diencephalon, and mesencephalon. In the anterior hypothalamus, high density of AR-ir was concentrated in several nuclei including the nucleus lateralis hypothalami, nucleus periventricularis magnocellularis, nucleus preopticus anterior, nucleus preopticus medialis, and nucleus preopticus paraventricularis magnocellularis. In the posterior hypothalamus, areas showing high density of AR-ir included the nucleus lateralis hypothalami posterioris, nucleus medialis hypothalami posterior, nucleus ectomamillaris, nucleus mamillaris lateralis, and nucleus tuberis. No sex differences in the density or localization of AR-ir were observed. Compared to brains from courting birds, AR-ir density was either extremely low or absent in most brain regions of brooding birds. It is concluded that in the dove, central ARs are closely associated with the sexual stages of the reproductive cycle.
Collapse
Affiliation(s)
- M D Belle
- Department of Biological Sciences, University of Central Lancashire, Preston, PR1 2HE, United Kingdom
| | | |
Collapse
|
9
|
Godwin J, Hartman V, Nag P, Crews D. Androgenic regulation of steroid hormone receptor mRNAs in the brain of whiptail lizards. J Neuroendocrinol 2000; 12:599-606. [PMID: 10849204 DOI: 10.1046/j.1365-2826.2000.00513.x] [Citation(s) in RCA: 9] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Sex and species differences in androgenic regulation of steroid hormone receptor mRNAs were examined in the diencephalon of two species of whiptail lizards: Cnemidophorus inornatus is a sexual species and the direct evolutionary ancestor to Cnemidophorus uniparens, an all-female parthenogenetic species. Lizards were gonadectomized and treated with different doses of either aromatizable testosterone or nonaromatizable dihydrotestosterone. The relative abundances of androgen-, oestrogen-, and progesterone-receptor mRNAs were compared in various nuclei following in situ hybridization with homologous riboprobes. A diversity of patterns in androgenic regulation was observed, with effects differing according to brain region, the steroid-receptor mRNA being considered and, in some cases, between androgens. In the ancestral sexual species, intact males had lower androgen-receptor mRNA abundances than castrated, blank-implanted males in the medial preoptic area. Testosterone significantly decreased androgen-receptor mRNA abundance in the medial preoptic area of castrated males. Males had higher androgen-receptor mRNA levels in the preoptic area than females generally and neither the sexual or parthenogenetic females showed a decrease in androgen-receptor mRNA with androgen treatment. Both testosterone and dihydrotestosterone increased oestrogen-receptor mRNA abundance in the ventromedial hypothalamus of C. inornatus, but no sex differences in this effect were observed. Gonadectomy decreased, whereas androgen treatment increased, progesterone-receptor mRNA abundance in the ventromedial hypothalamus. There was a sex difference in this response to androgen in the sexual species, with males having greater amounts than females in this brain area. The parthenogenetic species exhibited a similar pattern to females of the sexual species, but the levels were higher overall, possibly because Cnemidophorus uniparens is triploid. The periventricular preoptic area showed a different pattern, with testosterone treatment increasing progesterone-receptor mRNA abundance in both sexes of the sexual species and in the parthenogenetic species, while dihydrotestosterone did not. The diversity of patterns in androgen effects indicates that gonadal sex, aromatization of androgen, and perhaps gene dosage all influence the expression of steroid-receptor mRNAs in the lizard brain.
Collapse
Affiliation(s)
- J Godwin
- Department of Zoology, University of Texas at Austin, Austin, TX 78712, USA
| | | | | | | |
Collapse
|
10
|
Thakur MK, Asaithambi A, Mukherjee S. Synthesis and phosphorylation of androgen receptor of the mouse brain cortex and their regulation by sex steroids during aging. Mol Cell Biochem 2000; 203:95-101. [PMID: 10724337 DOI: 10.1023/a:1007064307220] [Citation(s) in RCA: 17] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/22/2022]
Abstract
To examine the synthesis and phosphorylation of androgen receptor (AR) and their regulation by sex steroids, adult (24 weeks) and old (65 weeks) male and female mice were gonadectomized and administered with testosterone and estradiol. AR amount, synthesis and phosphorylation were measured in the brain cortex by immunoblotting and immunoprecipitation using antibody raised against rat AR transactivation domain (TAD) which was expressed in E. coli as a fusion protein. We found that the amount of AR was high in adult and declined in old mice of both sexes. Administration of testosterone and estradiol significantly down-regulated the level of AR in old male and adult female. Similarly, the rate of AR synthesis also declined with age. Exogenous treatment of gonadectomized mice with testosterone and estradiol reduced the extent of synthesis significantly in all groups except in old female. No sex-dependent variation was noticed either in the level or synthesis of AR. In contrast, the extent of phosphorylation was higher in old mice of both sexes as compared to their adult counterparts. Testosterone and estradiol supplementation resulted in remarkable increase in AR phosphorylation in all groups. Thus it is evident from our findings that the amount and synthesis of AR decrease but phosphorylation of AR increases in the brain cortex with advancing age of mice and they are regulated by testosterone and estradiol in age- and sex-specific manner.
Collapse
Affiliation(s)
- M K Thakur
- Biochemistry and Molecular Biology Laboratory, Centre of Advanced Study in Zoology, Banaras Hindu University, Varanasi, India
| | | | | |
Collapse
|
11
|
Abdelgadir SE, Roselli CE, Choate JV, Resko JA. Androgen receptor messenger ribonucleic acid in brains and pituitaries of male rhesus monkeys: studies on distribution, hormonal control, and relationship to luteinizing hormone secretion. Biol Reprod 1999; 60:1251-6. [PMID: 10208992 DOI: 10.1095/biolreprod60.5.1251] [Citation(s) in RCA: 63] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/01/2022] Open
Abstract
Because the distribution and hormonal regulation of the androgen receptor (AR) mRNA in brains and pituitaries of adult rhesus monkeys have not been studied, we cloned and sequenced a 329-base pair segment of the 5' coding region of the rhesus AR cDNA. Monkey AR cDNA was 99% identical with the human sequence and 96% homologous with the rat sequence. Using a ribonuclease protection assay, we studied the distribution and regulation of AR mRNA in brains and anterior pituitary glands of three groups of male rhesus monkeys: intact (n = 3), castrated (Cx, n = 4), and Cx treated with testosterone (n = 6). Serum testosterone levels of Cx males treated with testosterone differed significantly (p < 0.05) in the morning but not in the evening hours from those in intact controls. Serum LH concentrations were significantly suppressed (p < 0.05) in both morning and evening serum samples of testosterone-treated males compared to intact controls. We found the highest concentrations of AR mRNA in the medial basal hypothalamus, the bed nucleus of the stria terminalis, the medial preoptic area-anterior hypothalamus, and the lateral dorsomedial hypothalamus. Intermediate amounts were found in the septum and amygdala. Low amounts were found in the hippocampus, cingulate cortex, parietal cortex, and cerebellum. The anterior pituitary gland also contained a large amount of AR mRNA. Surprisingly, neither Cx for 3 wk nor Cx plus testosterone replacement for 3 wk significantly affected AR mRNA in any brain area or in the pituitary gland. The present study demonstrates that the effectiveness of testosterone as a regulator of LH secretion in male monkeys is not related to changes of AR mRNA in the brain or pituitary gland. It appears that AR mRNA in the monkey brain and pituitary gland is not regulated at the transcriptional level by androgen.
Collapse
Affiliation(s)
- S E Abdelgadir
- Department of Physiology and Pharmacology, School of Medicine, Oregon Health Sciences University, Portland, Oregon 97201-3098, USA
| | | | | | | |
Collapse
|
12
|
Apostolinas S, Rajendren G, Dobrjansky A, Gibson MJ. Androgen receptor immunoreactivity in specific neural regions in normal and hypogonadal male mice: effect of androgens. Brain Res 1999; 817:19-24. [PMID: 9889303 DOI: 10.1016/s0006-8993(98)01180-9] [Citation(s) in RCA: 34] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
This study examined the distribution and regulation of androgen receptor immunoreactivity (IR) in the brain of the hypogonadal (hpg) male mouse, genetically deficient in GnRH. Five groups of animals were studied: intact, castrated, or castrated and testosterone propionate (TP)-treated normal adult male mice, and intact or TP-treated hpg adult male mice. All groups were studied 1 week after treatment. Five regions of the brain with high concentrations of androgen receptors in normal animals were examined, including the medial preoptic area, the lateral ventral septum, the ventromedial hypothalamus, the bed nucleus of the stria terminalis and the medial amygdala. The results showed that the congenital absence of GnRH results in minimal expression of androgen receptor-IR in mice in all regions examined. However, treatment with exogenous testosterone for 1 week was sufficient to induce the numbers of neurons containing androgen receptors, as detected by immunocytochemistry, into the range seen in normal male mice in all the areas studied except the VMH. Similar plasticity was also observed in normal males after 1 week of castration and TP replacement.
Collapse
Affiliation(s)
- S Apostolinas
- Department of Medicine, Mount Sinai School of Medicine, Box 1055, 1 Gustave L. Levy Place, New York, NY 10029, USA
| | | | | | | |
Collapse
|