TY - JOUR A1 - , T1 - Testosterone alters membrane binding of progesterone in male rat brains JO - Eur. J. Anat. SN - 1136-4890 Y1 - 2001 VL - 5 SP - 37 EP - 45 UR - http://www.eurjanat.com/web/paper.php?id=01010037 KW - bovine serum albumin KW - estradiol benzoate KW - progesterone KW - sodium iodide i 125 KW - testosterone KW - amygdaloid nucleus KW - animal experiment KW - animal tissue KW - article KW - autoradiography KW - central nervous system KW - gonadectomy KW - hormone action KW - hypothalamus KW - image analysis KW - male KW - medial preoptic area KW - membrane binding KW - nonhuman KW - radioiodination KW - rat KW - sexual behavior KW - thalamus midline nucleus N2 - The steroid progesterone (P) is important in control of male sexual behaviors. In this study binding sites for P conjugated to bovine serum albumin (P-BSA) were analyzed in the brains of gonadectomized male rats that were implanted with silastic capsules either filled with testosterone or empty. Frozen brains were sliced, thaw mounted on microscope slides, and incubated with radiolabeled P-BSA (P-[125I-BSA]) alone or with 1000 fold P-BSA competitor. Microscope slides were then dried, dipped in photographic emulsion and placed in light-tight boxes for four days before being developed and counterstained. Grain densities over cells were then analyzed with an image analysis system. Testosterone treatment significantly increased specific binding of P-[125I-BSA] in the caudal medial basal hypothalamus, the paraventricular nucleus-anterior hypothalamus, and the medial preoptic area. Testosterone treatment significantly decreased P-[125I-BSA] binding in the amygdala. There was no significant effect of testosterone in the rostral medial basal hypothalamus. Testosterone treatment changes P-[125I-BSA] binding in several areas that are important for male sexual behavior suggesting a function for P-[125I-BSA] binding sites in endocrine systems and behavior. ER -