Sulfonylurea receptor mRNA expression in pituitary macroadenomas.
ATP-sensitive K+ (KATP) channels modulated by sulfonylurea compounds have been previously identified in the anterior pituitary of the rat and have been demonstrated to influence GH release. Recently, a sulfonylurea receptor (SUR) has been cloned from an islet cell tumor and identified as a member of the ATP binding cassette superfamily capable to coupling with inwardly rectifying potassium channels. To determine if the same receptor is expressed in pituitary tumors, SUR mRNA levels were measured in 28 human macroadenoma specimens using an RNase protection assay. All immunonegative, corticotrophin (ACTH), growth hormone (GH), and GH/prolactin (GH/Prl) immunostaining tumors expressed detectable amounts of SUR message. Among these tumors, only the GH and GH/ Prl adenomas were functional. Of the tumors immunostaining for luteinizing hormone (LH), follicle-stimulating hormone (FSH), or both, SUR mRNA was present in small amounts in 5/11. Only 1/3 Prl immunostaining tumors contained SUR mRNA. In summary, we have demonstrated that SUR mRNA expression is common in several types of silent pituitary adenomas and in functional tumors that secrete GH. Lower levels are seen in some gonadotrophin immunostaining tumors.
Zhu
Z
Z
Section of Endocrine Neoplasia and Hormonal Disorders, U.T.M.D. Anderson Cancer Center, Houston 77030, USA.
McCutcheon
I E
IE
Lopes
M B
MB
Laws
E R
ER
Wagner
V L
VL
Bruner
J M
JM
Fuller
G N
GN
Langford
L A
LA
Ang
L W
LW
Friend
K E
KE
D018528:ATP-Binding Cassette Transporters; D000236:Adenoma / Q000737:chemistry / Q000235:genetics*; D000324:Adrenocorticotropic Hormone / Q000032:analysis; D005640:Follicle Stimulating Hormone / Q000032:analysis; D015870:Gene Expression; D019382:Human Growth Hormone / Q000032:analysis; D006801:Humans; D007150:Immunohistochemistry; D007986:Luteinizing Hormone / Q000032:analysis; D008854:Microscopy, Electron; D010911:Pituitary Neoplasms / Q000737:chemistry / Q000235:genetics*; D015221:Potassium Channels / Q000235:genetics*; D024661:Potassium Channels, Inwardly Rectifying; D011388:Prolactin / Q000032:analysis; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger / Q000032:analysis*; D011955:Receptors, Drug / Q000235:genetics*; D012260:Ribonucleases; D064233:Sulfonylurea Receptors
D018528:ATP-Binding Cassette Transporters; D015221:Potassium Channels; D024661:Potassium Channels, Inwardly Rectifying; D015347:RNA Probes; D016372:RNA, Antisense; D012333:RNA, Messenger; D011955:Receptors, Drug; D064233:Sulfonylurea Receptors; D019382:Human Growth Hormone; D000324:Adrenocorticotropic Hormone; D011388:Prolactin; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone; D012260:Ribonucleases