REDUCED THYROID-STIMULATING HORMONE RESPONSE TO THYROTROPIN-RELEASING-HORMONE IN AUTISTIC BOYS

The thyroid-stimulating hormone (TSH) and prolactin responses to thyrotropin-releasing hormone (TRH) were compared among four groups of boys-41 autistic, 12 mentally retarded (MR), 12 with minimal brain dysfunction (MBD) and five controls. The autistic boys were divided into two groups: DQ(IQ) greater-than-or-equal-to 80 and DQ(IQ) < 80. Mean TSH basal and peak levels were significantly lower in both autistic groups than in the MR, MBD and control groups. Mean TSH peak value minus basal value (p-b) was significantly lower in both autistic groups than in the control group. Mean prolactin levels and p-b value did not differ among groups. It is suggested that there may be enhanced dopaminergic and/or reduced serotonergic activity in the central nervous system of autistic children, together with hypothalamic dysfunction.