Role of the new growth hormone-releasing secretagogues in the diagnosis of some hypothalamopituitary pathologies.
Growth hormone (GH)-releasing hormone (GHRH) and somatostatin have a dominant role in regulating GH secretion. However, results of studies using the new class of GH secretogogues, particularly GHRP-6, indicate that there may also be other, as yet undefined, hypothalamic mechanisms involved. Studies in adults with hypothalamopituitary disconnection (functional pituitary stalk transection), show GHRP-6-mediated GH release to be completely blocked, indicating a main action at the hypothalamic rather than the pituitary level. The synergistic effect of GHRH plus GHRP-6 administration on GH release seen in normal adults (and virtually unaffected by age, obesity, or sex) is also absent in these patients, providing further support for this conclusion. Studies of the effects of GHRP-6 in children with GH deficiency due to perinatal pituitary stalk transection have produced similar findings. It is suggested that the combined GHRH plus GHRH-6 test should be a promising tool for diagnosing GH deficiency states in both children and adults, and may identify a subgroup of patients with GH deficiency caused by interruption of the hypothalamopituitary connection.
Casanueva
F F
FF
Department of Medicine, Complejo Hospitalario Universitario de Santiago, Spain.
Micic
D
D
Pombo
M
M
Leal
A
A
Bokser
L
L
Zugaza
J L
JL
Dieguez
C
C
D000328:Adult; D001720:Birth Injuries / Q000378:metabolism; D005260:Female; D013006:Growth Hormone / Q000172:deficiency; D013007:Growth Hormone-Releasing Hormone / Q000031:analogs & derivatives*; D006801:Humans; D007027:Hypothalamic Diseases / Q000175:diagnosis*; D007030:Hypothalamo-Hypophyseal System / Q000503:physiopathology; D007231:Infant, Newborn; D007232:Infant, Newborn, Diseases; D010900:Pituitary Diseases / Q000175:diagnosis*; D010902:Pituitary Gland / Q000293:injuries; D011247:Pregnancy
D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone