Nursing Pharmacology Chapter 32: Hypothalamic and Pituitary Hormones
Hypothalamic growth hormone-releasing hormone (GHRH): pituitary growth hormone (GH) secretion
GHRH belongs to a family of molecules including:
Secretin, VIP, gastric inhibitory peptide (GIP), glucagon.
Major site of GHRH production: arcuate nucleus hypothalamus.
G protein-coupled transmembrane receptor
Activation : GH gene transcription, synthesis and GH release (cAMP mediated)
Growth hormone-releasing hormone:
44-amino acid peptide leads to GH release stimulation.
Activity is expressed in the first 29-amino acids.
Growth-hormon releasing hormone (GHRH) is also known as growth-hormone releasing factor (GRF), GHRF, somatoliberin or somatocrinin.
Growth hormone-releasing peptides
Groups of small, synthetic peptides
Stimulate GH secretion (similar to GHRH)
GHRH: Routes of administration:
Stimulation: growth hormone secretion only (anterior pituitary)
GHRH: evaluation of short children with subnormal GH response to:
Insulin-induced hypoglycemia, oral L-DOPA, IV arginine
Normal response in this group: GH deficiency secondary to hypothalamic dysfunction
Subnormal response in this group: pituitary or hypothalamic dysfunction
Growth hormone level increase following GHRH: favorable clinical response to GHRH treatment
Facial flushing; injection site discomfort (nasal GHRP-2 appears to be well tolerated).
Primary Reference: Fitzgerald, P.A. and Klonoff, D.C. Hypothalamic and Pituitary Hormones, in Basic and Clinical Pharmacology, (Katzung, B. G., ed) Appleton-Lange, 1998, pp 603-618.
Primary Reference: Biller, Beverly M. K. and Daniels, Gilbert, H. Neuroendocrine Regulation and Diseases of the Anterior Pituitary and Hypothalamus, In Harrison's Principles of Internal Medicine 14th edition, (Isselbacher, K.J., Braunwald, E., Wilson, J.D., Martin, J.B., Fauci, A.S. and Kasper, D.L., eds) McGraw-Hill, Inc (Health Professions Division), 1998, pp 1972-1998