Growth hormone (GH) release by arginin-vasotocin (AVT) given intranasally in sexually immature children.

: Eighteen healthy children were given 50 micrograms synthetic AVT intranasally and samples of serum for GH, magnesium and alpha-amino-nitrogen were drawn 30, 60 and 120 minutes later. There was a significantly different mean of GH peak level (13.1 +/- 3.02 microU/ml) which occurred generally at 30 minutes. The number of GH responders (i.e. peak level greater than 15 microU/ml) was of 7/18. The means of chemical determinations elicited little though opposite changes: slight increases in magnesium and slight decrease in alpha-amino-nitrogen. In a separate day, a sleep test of 30 minutes-duration performed in the morning resulted in a significantly greater GH peak level (28.2 +/- 9.7 microU/ml) but the number of GH responders was nearly the same (6/18). The serum magnesium levels following sleep decreased slightly and unsignificantly. The involvement of serotonergic neurons in mediating GH-releasing effects of AVT is briefly discussed.