Distribution of Androgen Receptor mRNA in the Green Anole Brain. Rosen G., Matthews J., Zacharewski T., and Wade J.

To better understand androgen-dependent reproduction in the green anole lizard, the neuronal distribution of androgen receptor (AR) mRNA was determined using in situ hybridization. A partial cDNA of the anole AR was cloned using two degenerate primers derived from a consensus sequence of 10 known AR sequences from multiple species. Total RNA extracted from the kidney of adult male anoles was reverse transcribed and PCR amplified to generate a 697 bp fragment that included part of the C, the entire D, and part of the E domains. The predicted amino acid sequence shares 91% identity with the corresponding region of human AR and 88% identity to a smaller partial sequence obtained from whiptail lizards. In situ hybridization with a 35S- antisense riboprobe consistently revealed specific labeling in many areas of male and female brains, including the preoptic area, septum, amygdala, striatum, premammillary nucleus, ventromedial nucleus of the hypothalamus, torus semicircularis, and brainstem motor nuclei. Specific labeling also occurred in the renal sex segment of the kidney (positive control), which has a function similar to the mammalian prostate. No specific labeling was observed in brain or kidney sections exposed to the sense riboprobe. The localization of AR mRNA in the anole brain suggests potential targets for androgen action in the regulation of sexual behaviors and other related functions in this species. Supported by NIH NRSA MH12361 to G.R., NSF grant IBN-9733074 to J.W., and USA EPA grant R 826301-01-0 to T.Z.