Sexual dimorphism in rat oxytocinergic hypothalamic regions.

Oxytocin (OT), a nonapeptide of the hypothalamo- neurohypophyseal system is known to be important for milk ejection and uterus contraction in females and for erection and seminal emissions in males. These sex-specific functional properties imply differential distribution of OT in the hypothalamus. In the present study, complete series of vibratome sections of male and female rat brains were stained for OT with either immunoperoxidase or immunofluorescence in order to evaluate such sex differences. While no significant differences were found in the classical magnocellular nuclei, females had more OT neurons in the zona incerta and the retrochiasmatic portion of the supraoptic nucleus. In males, the lateral subcommissural nucleus and the lateral preoptic area contained significantly more OT perikarya. These sexually dimorphic locations of O T - e x p ressing neuro ns may be th e n eu - roanatomical correlates of known gender-specific functions of O

Localization of the apoptosis repressor ARC and anti-apoptotic factor FLIP in endomyocardial biopsies of cardiomyopathy patients.

Endomyocardial biopsies from patients with dilated cardiomyopathy were obtained by cardiac catheterization. Tissue samples were embedded in epoxy resin and sectioned into serial semithin sections for immunhistochemical visualization of either the apoptosis re p ressor protein or the FLICE inhibitory protein. Colocalization of apoptosis re p ressor protein and FLICE inhibitory portein was observed in cardiac myocytes, with nuclear DNA fragmentation and myofibrillary degradation. Intact myocytes were devoid of FLICE inhibitory p rotein and apoptosis re p ressor protein staining. FLICE (Fas-associated death-domain-like IL-1 - converting enzyme) inhibitory protein and apoptosis re p ressor protein were localized in the perinuclear cytoplasm, mainly in areas that showed myofibrillary degradation as visualized by fluore scence microscopy. FLICE inhibitory and apoptosis re p ressor proteins may be intracellular markers for monitoring myocardial damage in several cardiac diseases in humans

Testosterone alters membrane binding of progesterone in male rat brains.

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-[1 2 5I - B S A ] ) 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 w e re then analyzed with an image analysis system. Te s t o s t e rone treatment significantly i n c reased specific binding of P-[1 2 5I-BSA] in the caudal medial basal hypothalamus, the paraventricular nucleus-anterior hypothalamus, and the medial preoptic area. Tes tosterone treatment significantly decreased P-[1 2 5I - B S A ] binding in the amygdala. There was no significant effect of testosterone in the rostral medial basal hypothalamus. Testosterone treatment changes P-[1 2 5I-BSA] binding in several are a s that are important for male sexual behavior suggesting a function for P-[1 2 5I-BSA] binding sites in endocrine systems and behavior