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CONTINUOUS INFUSION OF GROWTH HORMONE RELEASING HORMONE DOES NOT ALTER THE GROWTH HORMONE RESPONSE TO DIFFERENT STRESS STIMULI
Author(s) -
SCHULTE H. M.,
ALLOLIO B.,
FROHWEIN U. S.,
BENKER G.,
REINWEIN D.
Publication year - 1986
Publication title -
clinical endocrinology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.055
H-Index - 147
eISSN - 1365-2265
pISSN - 0300-0664
DOI - 10.1111/j.1365-2265.1986.tb03603.x
Subject(s) - endocrinology , medicine , bolus (digestion) , somatotropic cell , growth hormone–releasing hormone , growth hormone , hormone , continuous infusion , peptide hormone , anterior pituitary , insulin
SUMMARY Continuous infusion of GHRH, as well as a bolus injection of GHRH, specifically stimulates the release of GH by the anterior pituitary. However, repetitive bolus injections of GHRH result in diminished responses of GH, while a constant infusion of GHRH cannot maintain high serum GH levels. To investigate whether different GH‐releasing stimuli are able further to challenge the somatotroph being exposed to continuous infusion of GHRH, we determined the GH response to insulin‐induced hypoglycaemia and bicycle exercise. Six normal volunteers received a bolus of 50 μg GHRH or vehicle followed by a continuous infusions of GHRH 1–29 amide (lμg/kg/h) or vehicle for 2.5 h. GHRH bolus and infusion resulted in elevated GH levels, but GH levels fell to values not significantly different from baseline levels after 150 min, GH plasma levels rose again, however, in response to insulin hypoglycaemia and bicycle exercise after both GHRH or vehicle infusion. Thus, the somatotroph's responsiveness to GHRH remains intact to respond to stress stimuli after continuous GHRH infusion.