Abstract
The intrinsic expression of sex hormone binding globulin (SHBG) in magnocellular hypothalamic
neurons, in part co-localized with either vasopressin or oxytocin, was recently described.
This study is focused on the ultrastructural localization of SHBG in the hypothalamo-neurohypophyseal
pathway in rats. Immunostaining for SHBG in the hypothalamic perikarya was increased
by colchicine treatment, indicating that the steroid-binding globulin is subject to
rapid axoplasmic transport along with the classical posterior lobe peptides. With
immunoelectron-microscopic double labeling, we found co-localization of oxytocin and
sex hormone binding globulin in a portion of the large dense-core vesicles in paraventricular
and supraoptic perikarya and in axonal varicosities in the median eminence and in
the posterior lobe. Our observations show that SHBG is processed, transported and
stored along with oxytocin suggesting that SHBG is released from nerve terminals in
the posterior lobe, the median eminence and possibly the brain similarly to and in
conjunction with oxytocin.
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Dr. Zsófia Herbert
Department of Neurobiology · LMU-Biozentrum
Grosshaderner Str. 2 · 82152 Planegg-Martinsried · Germany
Phone: +49(89)218074313
Fax: +49(89)218074304
Email: telapo@gmx.de
