Growth hormone secretion in pubertal and adult subjects.
GH responsiveness to insulin-induced hypoglycaemia and its circadian secretion were studied in a group of subjects in different pubertal stages. The GH peak after insulin was minimal in stage 1 boys (7.6 +/- 1.3 (SEM) ng/ml) and increased progressively, in parallel with pubertal maturation, reaching a maximum in the adult state (20 +/- 4.0 ng/ml); the basal value was superimposable in all groups studied. The circadian secretion showed a sleep-related surge which was almost identical in the different stages; however in pubertal stage 1 boys multiple secretory peaks were observed, mainly during waking hours. A statistically significant difference (P less than 0.05) was observed in the mean concentration recorded during the day with a maximum in stage 1 boys (2.7 +/- 0.2 ng/ml) and a gradual decrease to a minimum in adults (1.2 +/- 0.3 ng/ml). This pattern seems to suggest that pulsatile rhythm is present in boys, similar to that observed for gonadotrophins.
D000293:Adolescent; D000328:Adult; D000367:Age Factors; D002648:Child; D002940:Circadian Rhythm; D013006:Growth Hormone / Q000378:metabolism*; D006801:Humans; D007328:Insulin / Q000494:pharmacology; D008297:Male; D008875:Middle Aged; D011627:Puberty
D007328:Insulin; D013006:Growth Hormone