TY - JOUR
T1 - A cryptic peptide (160—169) of thyrotropin-releasing hormone prohormone demonstrates biological activity in vivo and in vitro
AU - Carr, Frances E.
AU - Fein, Henry G.
AU - Fisher, Carolyn U.
AU - Wessendorf, Martin W.
AU - Smallridge, Robert C.
PY - 1992/12
Y1 - 1992/12
N2 - TRH is synthesized as a precursor peptide containing five copies of the sequence Gln-His-Pro-Gly, QHPG, flanked by paired basic amino acids, and linked by other peptides. We tested one cryptic peptide, PPT (160-169, SFPWMESDVT), as a possible physiological regulator of pituitary activity in vivo. Male rats were cannulated (jugular) and received a single dose of either PPT or TRH (10-8-10-6M). PPT caused no consistent effects on either TSH or PRL secretion, while TRH stimulated the secretion of both hormones. However, PPT stimulated a dose-dependent increase in both pituitary TSHβ and PRL mRNA content at 240 min similar to TRH. In primary cultures of rat pituitar-ies, PPT stimulated a maximum 4-fold increase in TSHβ mRNA and a 2-fold increase in PRL mRNA in 4 h, while TRH increased both TSHβ and PRL mRNA approximately 3-fold. Again, PPT had no significant effect on TSH or PRL secretion into the medium. Thus, PPT appears to be a physiological regulator of both TSH and PRL synthesis, but, unlike TRH, does not act as a secretagogue.
AB - TRH is synthesized as a precursor peptide containing five copies of the sequence Gln-His-Pro-Gly, QHPG, flanked by paired basic amino acids, and linked by other peptides. We tested one cryptic peptide, PPT (160-169, SFPWMESDVT), as a possible physiological regulator of pituitary activity in vivo. Male rats were cannulated (jugular) and received a single dose of either PPT or TRH (10-8-10-6M). PPT caused no consistent effects on either TSH or PRL secretion, while TRH stimulated the secretion of both hormones. However, PPT stimulated a dose-dependent increase in both pituitary TSHβ and PRL mRNA content at 240 min similar to TRH. In primary cultures of rat pituitar-ies, PPT stimulated a maximum 4-fold increase in TSHβ mRNA and a 2-fold increase in PRL mRNA in 4 h, while TRH increased both TSHβ and PRL mRNA approximately 3-fold. Again, PPT had no significant effect on TSH or PRL secretion into the medium. Thus, PPT appears to be a physiological regulator of both TSH and PRL synthesis, but, unlike TRH, does not act as a secretagogue.
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U2 - 10.1210/endo.131.6.1446607
DO - 10.1210/endo.131.6.1446607
M3 - Article
C2 - 1446607
AN - SCOPUS:0026464519
SN - 0013-7227
VL - 131
SP - 2653
EP - 2658
JO - Endocrinology
JF - Endocrinology
IS - 6
ER -