Changes in prolactin cells caused by partial hepatectomy in the rat.

In order to study ultrastructure alterations in prolactin (PRL)-secreting cells, PRL cells of the anterior pituitary glands of partially hepatectomized female rats were observed by the protein A-gold procedure with the electron microscope. Simultaneously, their serum PRL and estradiol (E2) levels were measured by radioimmunoassay. After about 70% hepatectomy PRL cells were remarkably changed, that is active granule extrusion, prominent Golgi vesicles and a hypertrophic rough endoplasmic reticulum were observed. These changes were most remarkable on day 3 after the operation. Significant increases in serum PRL and E2 were also seen following partial hepatectomy. It may be assumed that the morphological changes in PRL cells and the elevation of serum PRL were probably due to surgical stress and to the diminution of E2 receptors in the liver after partial hepatectomy in the rat.