Changes in growth hormone and prolactin release after superior cervical ganglionectomy of rats

Superior cervical ganglionectomy (SCG X) decreased significantly serum growth hormone (GH) levels in rats 14-96 h after surgery, during and immediately after anterograde degeneration of regional sympathetic terminals. At later times (up to 28 days after SCG X) an increase in serum GH was observed. SCG X augments prolactin (PRL) release, but only at the earliest time examined (14 h after surgery). Injection of the alpha-adrenoceptor blocker, phenoxybenzamine, but not of the beta-blocker, propranolol, negated the depression in serum GH found in SCG X rats 14 h after surgery, without affecting PRL release.