The growth hormone (GH) response to GH-releasing peptide (His-DTrp-Ala-Trp-DPhe-Lys-NH2), GH-releasing hormone, and thyrotropin-releasing hormone in acromegaly.
In patients with acromegaly, GH-producing pituitary tumors release GH in response to specific stimuli such as GH-releasing hormone (GHRH) and are also responsive to a variety of nonspecific stimuli, such as TRH or GnRH, and may exhibit paradoxical responses to glucose and dopamine. In healthy humans, the synthetic peptide GH-releasing peptide (GHRP) (His-D-Trp-Ala-Trp-D-Phe-Lys-NH2) releases GH by a putative mechanism of action that is independent of GHRH. How these tumors respond to GHRP is not well characterized. We studied the GH responses to GHRH, GHRP, and TRH stimulation in 11 patients with active acromegaly. The peak GH responses to GHRP and GHRH were not correlated (r = 0.57; P = 0.066). In contrast, the peak GH responses to GHRP and TRH were highly correlated (r = 0.95; P < 0.001). In conclusion, in patients with acromegaly, the GH response to GHRP is qualitatively normal and does not appear to depend on GHRH.
Alster
D K
DK
Department of Internal Medicine, Tulane University Medical School, New Orleans, Louisiana 70112.
Bowers
C Y
CY
Jaffe
C A
CA
Ho
P J
PJ
Barkan
A L
AL
D000172:Acromegaly / Q000503:physiopathology*; D000293:Adolescent; D000328:Adult; D000368:Aged; D000595:Amino Acid Sequence; D005260:Female; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000494:pharmacology*; D006728:Hormones / Q000494:pharmacology; D006801:Humans; D007700:Kinetics; D008297:Male; D008875:Middle Aged; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000494:pharmacology*; D013973:Thyrotropin-Releasing Hormone / Q000494:pharmacology*
D006728:Hormones; D009842:Oligopeptides; C041048:growth hormone releasing hexapeptide; D013973:Thyrotropin-Releasing Hormone; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone