Does prolactin releasing peptide receptor regulate prolactin-secretion in human pituitary adenomas?
Prolactin-releasing peptide (PrRP) and its receptor (PrRP-R) have recently been characterized and cloned. PrRP functions as a prolactin-secreting factor through binding with PrRP-R, which is extensively expressed in the human pituitary. We studied the expression of PrRP-R in human pituitary adenomas. Pituitary adenomas were collected from 13 patients by transsphenoidal resection. Six patients had prolactin-secreting adenomas, three had adrenocorticotropic hormone-secreting adenomas, one had a growth hormone -secreting adenoma, and three had non-secreting adenomas. All pituitary adenomas examined by reverse transcription-polymerase chain reaction analysis expressed PrRP-R. When semiquantitative competitive PCR was performed to determine the relative amounts of the PrRP-R mRNA expression level, there was no correlation between plasma prolactin levels and PrRP-R expression levels. These results suggest that the plasma prolactin level is regulated by means other than signal transduction through PrRP-R activation.
Takahashi
K
K
Department of Physiological Chemistry, School of Pharmaceutical Sciences, Showa University, 1-5-8, Hatanodai, Shinagawa-ku, 142-8555, Tokyo, Japan. takahask@pharm.showa-u.ac.jp
Abe
T
T
Matsumoto
K
K
Tomita
M
M
D000324:Adrenocorticotropic Hormone / Q000378:metabolism; D019382:Human Growth Hormone / Q000378:metabolism; D006801:Humans; D007150:Immunohistochemistry; D010911:Pituitary Neoplasms / Q000378:metabolism* / Q000473:pathology; D011388:Prolactin / Q000097:blood / Q000378:metabolism*; D015175:Prolactinoma / Q000378:metabolism / Q000473:pathology; D012333:RNA, Messenger / Q000096:biosynthesis; D018013:Receptors, Neuropeptide / Q000235:genetics / Q000378:metabolism*; D020133:Reverse Transcriptase Polymerase Chain Reaction; D015398:Signal Transduction
D012333:RNA, Messenger; D018013:Receptors, Neuropeptide; C400801:receptor, prolactin-releasing peptide; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin