No abstract available.
Neuropeptides* ; Pituitary Hormones*

No abstract available.
Neuropeptides* ; Pituitary Hormones*

We investigated the effect of alpha-subunit of the stimulatory GTP-binding protein (Galphas) gene mutation on the expression of the thyrotropin-releasing hormone (TRH) receptor (TRH-R) gene in GH3 cells and in growth hormone (GH)-secreting adenomas of acromegalic patients. In the presence of cycloheximide, forskolin and isobutylmethylxanthine, cholera toxin, and GH-releasing hormone (GBRH) decreased rat TRH-R (rTRH-R) gene expression by about 39%, 43.7%, and 46.7%, respectively. Transient expression of a vector expressing mutant-type Galphas decreased the rTRH-R gene expression by about 50% at 24 h of transfection, whereas a wild-type Galphas expression vector did not. The transcript of human TRH-R (hTRH-R) gene was detected in 6 of 8 (75%) tumors. Three of them (50%) showed the paradoxical GH response to TRH and the other three patients did not show the response. The relative expression of hTRH-R mRNA in the tumors from patients with the paradoxical response of GH to TRH did not differ from that in the tumors from patients without the paradoxical response. Direct PCR sequencing of GALPHAs gene disclosed a mutant allele and a normal allele only at codon 201 in 4 of 8 tumors. The paradoxical response to TRH was observed in 2 of 4 patients without the mutation, and 2 of 4 patients with the mutation. The hTRH-R gene expression of pituitary adenomas did not differ between the tumors without the mutation and those with mutation. The present study suggests that the expression of TRH-R gene is not likely to be a main determinant for the paradoxical response of GH to TRH, and that Galphas mutation may suppress the gene expression of TRH-R in GH-secreting adenoma. However, a certain predisposing factor(s) may play an important role in determining the expression of TRH-R.
Acromegaly ; Adenoma ; Alleles ; Animals ; Cholera Toxin ; Codon ; Colforsin ; Cycloheximide ; Gene Expression ; Growth Hormone ; GTP-Binding Proteins ; Humans ; Pituitary Neoplasms ; Polymerase Chain Reaction ; Rats ; Receptors, Thyrotropin-Releasing Hormone* ; RNA, Messenger* ; Thyrotropin-Releasing Hormone ; Transfection

BACKGROUND: It has been already known that each trophic hormone in combined pituitary responsiveness according to gender and age brings about variable response, but in Korea, there has been no actual data. In this study, in order to assess the pituitary responsiveness, a combined pituitary stimulation test was performed in Korean subjects with the variation in CRH, GHRH, GnRH, and TRH according to their age and gender. Were these the variables that were changed according to age and gender? Clarify that. Also, it might be good to write out the abbreviations.) METHOD: Fourteen physically and mentally healthy male subjects and fourteen female subjects, also physically and mentally healthy, underwent the combined anterior pituitary stimulation test by CRH, GHRH, LHRH, and TRH. Each gender group was divided further into young(meanSE; male: 231, female: 221) and old (mean; male: 513, female: 522) groups. RESULTS: There were significant differences between the gender and age groups. The Peak GH level and maximal GH increment were significantly increased in young men compared to old men. The Peak ACTH level and maximal ACTH increment were significantly increased in old men as opposed to young men. The Peak PRL level, maximal PRL increment, Peak TSH level, and maximal TSH increment were significantly increased in old women compared to old men. The Peak FSH level was significantly increased in the two old groups compared to the young groups, which showedindependence in gender, and the maximal FSH increment was significantly increased in old men when compared with the young men. CONCLUSION: These results show that in order to for accurate interpretation of the response from the combined pituitary stimulation test, it is necessary to consider age and gender of the subjects. We suggest response values of the combined pituitary stimulation test in terms of age and gender in healthy Korean subjects.
Adrenocorticotropic Hormone ; Corticotropin-Releasing Hormone ; Female ; Gonadotropin-Releasing Hormone* ; Growth Hormone-Releasing Hormone ; Humans* ; Korea ; Male