High impact information on AR

• Androgen action appeared to be mediated by classical androgen receptors (ARs) expressed in oocytes, as androgen-induced maturation and signaling was specifically attenuated by AR antagonists [1].
• We demonstrated that the anesthetic propanethiol, or alternatively, propyl methanethiosulfonate, covalently binds to cysteine residues introduced into a specific second transmembrane site in glycine receptor and gamma-aminobutyric acid type A receptor subunits and irreversibly enhances receptor function [2].
• The present evidence suggests that the activity of the neuronal Na+ and Ca2+ channels and the ligand-gated gamma-aminobutyrate type A receptor channel are under the control of protein kinase C and that neurotransmitters that activate protein kinase C could profoundly affect neuronal signaling [3].
• To shed light on the nature and evolution of structure-function relations in the androgen receptor (AR), we have undertaken a comparative analysis of all available AR and other steroid receptor sequences [4].
• Androgen upregulates expression of AR mRNA in N [5].

Biological context of AR

• Short exposures to androgen result in a biphasic response of AR mRNA levels; a marked down-regulation (4 hr) is followed by recovery at 8 hr (males) or 48 hr (females) [6].
• Neither the axotomy- nor the androgen-induced increase in number of cells expressing AR mRNA is attributable to cell proliferation [5].
• Axotomy-induced upregulation of AR expression may facilitate the trophic actions of androgens [5].
• Interestingly, reduction of classical androgen receptor (AR) expression by RNA interference abrogated testosterone's effects on GIRK activity at low, but not high, steroid concentrations [7].
• The tadpole larynx strongly expresses AR mRNA, expression does not require exposure to TH nor is expression diminished in culture [8].

Anatomical context of AR

• Following longer periods of androgen treatment (3 weeks), AR mRNA expression is down-regulated and male-typical differentiation of elastic cartilage is induced in both sexes [6].
• To determine whether changes in androgen receptor (AR) expression are associated with trophic actions of androgens, we have examined the laryngeal motor nucleus (N. IX-X) of Xenopus laevis 1 and 5 months after section of the laryngeal nerve [5].
• Although expression of AR mRNA is widespread throughout the CNS, cells of cranial nerve nucleus IX-X (N.IX-X) and spinal cord display the highest in situ hybridization signals in their cytoplasm [9].
• Immunocytochemistry employing an antibody against the androgen receptor (AR) indicated that the receptor is present in myonuclei of all muscles of the forelimb [10].
• Nuclease protection assays demonstrate that the expression of AR mRNA is higher in the brain stem than in the telencephalon and diencephalon [9].

Associations of AR with chemical compounds

• In situ hybridization was used to recognize cells expressing mRNA for the Xenopus AR and bromodeoxyuridine to assess cell proliferation [5].
• In contrast, progesterone bound with high affinity to both the Xenopus PR and AR, indicating that progesterone might signal and promote maturation through both receptors, regardless of its concentration [7].
• Increased expression of AR mRNA in the brain of DHT treated animals is also apparent in nuclease protection assays [9].
• Double labeling using horseradish peroxidase and digoxigenin labeled AR probes reveals that laryngeal and anterior spinal cord motor neurons express AR mRNA [9].
• Amino acids lining the channel of the gamma-aminobutyric acid type A receptor identified by cysteine substitution [11].

Analytical, diagnostic and therapeutic context of AR

• After 1 month of axotomy, the number of AR mRNA-expressing cells in N [5].
• Only one of the AR mRNA isoforms expressed in X. laevis is transcribed in the CNS as shown by Northern blot analysis [9].
• However, RT-PCR analysis revealed that AR mRNA is also expressed in other tissues although the levels are very low compared to that in the testis [12].
• The AR gene is present as a single copy in bullfrog based on Southern blot analysis of genomic DNA [12].
• Western blot analysis of whole tissue extracts showed the presence of AR protein in fore brain, heart, and testis [12].

References