The survey of pituitary development in rat and comparison of different fixative effects on its tissue preparation

The pituitary gland constitutes Anterior, intermediate (collectively, adenohypophysis), and posterior lobes. It is believed that pituitary arises from two different anlagen, the first one arises from Osteomodeum as an up growth to form Rathke’s pouch, and the second one, develops as a down growth from the floor of the diencephalon to form posterior pituitary gland. The aim of this study was to survey the pituitary developmental stages practically as a pilot study and comparison of Normalin, Carnoy’s, Bouin and B4G fixatives effects. In this experimental study, we used 5µm thickness Normalin, Carnoy’s, Bouin and B4G fixed, paraffin embedded serial sections. Rat embryonic sections from day 10 (E10) to 20(E20) of gestation (n=30) were stained with Haematoxyline and Eosin (H&E). The result of this study demonstrated that the formation of Rathke’s pouch started from E10, and changed during its morphogenesis to E20 to form pituitary gland. At the first developmental stage (E10) to17 (E17) gestational day all the adenohypophyseal cells reacted with Hematoxiline and reaction of some adenohypophyseal cells with Eosin started from gestational day18 (E18) and increased with proceeding differentiation during the following days and Carnoy’s fixed specimen yielded the best results effectively. Our findings indicate that practical review of Rathke’s pouch show changes during pituitary development and its cell differentiation using H&E staining and Carnoy’s fixative can be used in more advanced techniques to determine developmental stages.