Expression and alternative splicing of Pit-1 messenger ribonucleic acid in pituitary adenomas.
Twenty-eight human pituitary adenomas were analyzed for the expression of Pit-1 messenger ribonucleic acid (mRNA) by using reverse transcriptase-polymerase chain reaction analysis of frozen-section mRNA. Pit-1 mRNA was detected in all functioning tumors and in 9 of 11 nonfunctioning tumors. Pit-1 beta, which is a more active isoform of transcriptional factor for growth hormone than Pit- alpha and which arises from an alternative splicing mechanism, was detected in 14 of 17 functioning tumors and in 5 of 11 nonfunctioning tumors. The transcript that corresponds to Pit-1T, which increases thyroid-stimulating hormone beta promoter activity in rat thyrotropic tumor cells, was not found. There was no significant difference in the total Pit-1 (alpha+beta) mRNA expression level between functioning tumors and nonfunctioning tumors. Growth hormone-producing tumors and other pituitary adenomas also showed no significant difference in the Pit-1 beta/Pit-1 alpha expression ratio. Our data suggest that the major role of Pit-1 gene in pituitary adenoma might not be involved in the regulation of hormone production.
Hamada
K
K
Department of Neurosurgery, Kumamoto University Medical School, Kumamoto City, Japan.
Nishi
T
T
Kuratsu
J
J
Ushio
Y
Y
D000236:Adenoma / Q000235:genetics*; D017398:Alternative Splicing; D001483:Base Sequence; D004268:DNA-Binding Proteins / Q000235:genetics*; D018398:Homeodomain Proteins / Q000235:genetics; D006801:Humans; D015335:Molecular Probes / Q000235:genetics; D008969:Molecular Sequence Data; D010911:Pituitary Neoplasms / Q000235:genetics*; D016133:Polymerase Chain Reaction; D012333:RNA, Messenger / Q000235:genetics* / Q000378:metabolism; D050817:Transcription Factor Pit-1; D014157:Transcription Factors / Q000235:genetics*; D014158:Transcription, Genetic
D004268:DNA-Binding Proteins; D018398:Homeodomain Proteins; D015335:Molecular Probes; C494187:POU1F1 protein, human; D012333:RNA, Messenger; D050817:Transcription Factor Pit-1; D014157:Transcription Factors