The influence of age on human pancreatic growth hormone releasing hormone stimulated growth hormone secretion.
63 non-obese healthy subjects aged 18 to 95 years were investigated for age-dependence of GHRH-stimulated GH-secretion. In addition, priming of GH-secretion with three oral doses of propranolol (3 x 80 mg, the last dose 2 hours prior to the second GHRH-bolus) was carried out in 15 subjects below 40 years and 13 subjects older than 70 years. We found that mean maximal incremental GH-levels were inversely correlated with chronological age (r = -0.44, P = 0.001) of the probands. Propranolol premedication caused a significant rise of both basal and peak GHRH-induced relative increases in all subjects tested, whereas GHRH-induced relative increases of GH remained unchanged. In a well selected group of non-obese healthy subjects stimulated GH-secretion is found to undergo an aging process that is supposed to be of pituitary and suprapituitary origin. Priming GH-secretion with a beta-Blocker is possible both in young and very old healthy subjects and is likely to affect the basal GH secretory tone and not GHRH-stimulated GH-secretion.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology*; D005260:Female; D013006:Growth Hormone / Q000378:metabolism*; D013007:Growth Hormone-Releasing Hormone / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011433:Propranolol / Q000494:pharmacology
D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone; D011433:Propranolol