Growth hormone receptor gene: novel expression in pituitary tissue

Specific hybridization of polyadenylated RNA, extracted from rat, rabbit and human pituitary glands with a 638 bp rabbit GH receptor (rGHR) cRNA was demonstrated by Northern analysis. In-situ hybridization of tissue sections with the probe demonstrated the localization of rGHR mRNA throughout the rat pituitary gland and its presence in the anterior lobe of the rabbit pituitary. Growth hormone binding sites on pituitary membranes were not, however, demonstrated by radioligand binding studies. Thus, although the GH receptor gene is expressed in pituitary tissue, functional GH receptors may not be inserted into pituitary plasma membranes.