Hypothalamo-hypophyseal portal blood sampling from laboratory rats. The effects of endocrine manipulations on portal blood catecholamine concentrations.

We have obtained hypothalamo-hypophyseal portal blood using a modified Worthington-Fink technique, and measured the concentrations of catecholamines with a high pressure liquid chromatography - electrochemical detection system. The concentrations of noradrenaline, adrenaline and dopamine have been measured in portal blood after various endocrine manipulations, including adrenalectomy, orchidectomy and chemically induced hypothyroidism. After the induction of hypothyroidism, dopamine concentrations in portal blood increased. After orchidectomy, there was an increase in portal adrenaline concentration, though noradrenaline and dopamine were unchanged.