Growth hormone releasing factor: comparison of two analogues and demonstration of hypothalamic defect in growth hormone release after radiotherapy.

Abstract

Human pancreatic growth hormone releasing factor (hpGHRF(1-40)) stimulates the release of growth hormone in normal subjects and some patients with growth hormone deficiency. A study comparing the shorter chain amidated analogue hpGHRF(1-29) with an equivalent dose of hpGHRF(1-40) in seven normal subjects showed no significant difference In growth hormone response between the two preparations. Six

Dosimetry and growth hormone deficiency following cranial irradiation of childhood brain tumors

“…Radiation damage to the hypothalamus or pituitary probably involves a direct injury to these cells responsible for the hormonal secretion or an injury to the microvasculature inhibiting the transfer of the hypothalamic hormones to the pituitary. Many patients with radiation-induced GHD remain responsive to a bolus administration of growth hormone-releasing hormone, implying that the hypothalamus rather than the pituitary is the site of radiation damage [9][10][11][12][13][14]. Some clinical studies have indicated that the hypothalamus is more radiosensitive than the pituitary following lower dose irradiation of <40-50 Gy, whereas at higher doses of radiation there is evidence of both hypothalamic and pituitary dysfunction [15][16][17][18].…”

Corticotropin- and growth hormone-releasing factor (CRF and GRF) in the diagnosis of hypothalamo-pituitary diseases

“…In contrast to the CRF, deletion of C-terminal aminoacids of GRF does not reduce its biological activity [7,11,16]. Thus, the 29 N-terminal aminoacids of GRF (hpGRF 1-29) have the same biological activity as hpGRF 1-40 and hpGRF 1-44 [7,11].…”

“…Thus, the 29 N-terminal aminoacids of GRF (hpGRF 1-29) have the same biological activity as hpGRF 1-40 and hpGRF 1-44 [7,11]. Since the pancreatic GRF 1-44 is identical to the hypothalamic GRF [9], the term human (h) GRF seems to be adequate.…”

Effects of Acute Intravenous Injection of Two Growth Hormone-Releasing Hormones (GHRH 1&ndash;40 and 1&ndash;29) on Serum Growth Hormone and Other Pituitary Hormones in Short Children with Pulsatile Growth Hormone Secretion

“…GHRH is a peptide which exists in the human hypothalamus in two forms, one consisting of 40, the other of 44 amino acids [20]. The growth hormone(GH)-releasing activity seems to be located in the 1-29-NH2-terminal amino acid sequence of GHRH, as judged from in vitro and in vivo studies with the synthetic sequences [13,14,18,22], This peptide has, however, not been identified in the hypothalamus. Attempts have been made to use GHRH in the diagnosis of impaired GH secretion [4], as well as to promote grot in GH-deficient children [12,23,27,28,31,33,36].…”