Role of aging on growth hormone and prolactin release after growth hormone-releasing hormone and domperidone in man.
Growth hormone (GH) and prolactin (PRL) secretion after GH-releasing hormone (GHRH) and domperidone (DOM), an antidopaminergic drug which does not cross the blood-brain barrier (BBB), was evaluated in 8 healthy elderly men (65-91 years) and in 7 young adults (23-40 years). All received in random order at 2-day intervals: GHRH(1-40) (50 micrograms i.v.) bolus, DOM (5 mg/h) infusion, GHRH(1-40) (50 micrograms i.v.) plus DOM (5 mg/h i.v.), saline solution. In elderly men GH increase after GHRH was significantly lower than in young men. DOM alone did not change GH secretion in either of these groups, whereas it increased the GH response to GHRH only in young adults. PRL levels increased in both young and elderly men during both DOM and GHRH plus DOM, but the PRL release was more marked in young than in elderly men. Both integrated secretion of GH after GHRH and of PRL after DOM were inversely correlated to chronological age. Our data show an impairment of GH rise after GHRH and of PRL after DOM in elderly adults. It is also stressed that peripheral blockade of dopamine receptors by DOM is unable to amplify the GH response to GHRH only in elderly men. A reduction in GH release after GHRH might be related to aging, perhaps through a reduction of dopaminergic tonus.
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D000375:Aging; D004294:Domperidone; D013006:Growth Hormone / Q000097:blood*; D013007:Growth Hormone-Releasing Hormone; D006801:Humans; D008297:Male; D011388:Prolactin / Q000097:blood*
D004294:Domperidone; D011388:Prolactin; D013006:Growth Hormone; D013007:Growth Hormone-Releasing Hormone