Low doses of ipsapirone increase growth hormone but not oxytocin secretionin normal male and female subjects

Objective: The present study investigated whether administration of a 5-HT1 A receptor agonist would increase growth hormone (GH) and oxytocin levels i n normal human subjects, and whether the responses would be modified accord ing to the age and gender of the subjects. Methods: Ipsapirone (0.3 mg/kg b ody weight), or placebo was administered to 30 normal subjects (14 males, 1 9-74 years and 16 females, 22-69 years) using a randomized, double blind de sign. Results: Stimulation of GH secretion by ipsapirone was significantly greater in male compared to female subjects, with no apparent effect of age . Oxytocin secretion was not stimulated by ipsapirone compared to placebo i n any of the groups. Conclusions: The effects of gender and age on the degr ee of stimulation of GH secretion by 5-HT1A agonists in human subjects diff er from their effects on secretion of the hormones ACTH and cortisol. A hig her dose of ipsapirone is required to stimulate oxytocin secretion in norma l human subjects.