An improved fixation procedure for microtubules and microfilaments in cells of the anterior pituitary gland

A fixation procedure for the preservation of microtubules and microfilaments in anterior pituitary cells is presented. Small pieces of tissue were fixed at room temperature in a glutaraldehyde solution. The temperature was gradually reduced to 4–5°C before the tissue was post fixed. Post fixation was carried out using several changes of a mixture of cold glutaraldehyde and osmium tetroxide and then osmium tetroxide alone. The osmolarity of both fixing solutions was 400 milliosmoles. The procedure permits a clear visualization of both microtubules and microfilaments within anterior pituitary cells, particularly in regions where they are not ordinarily seen such as within the Golgi apparatus.