THE HYPOTHALAMIC-PITUITARY RESPONSE IN SLE - REGULATION OF PROLACTIN,GROWTH-HORMONE AND CORTISOL RELEASE

It has been suggested that neuroendocrine regulation plays an importan t role in the pathogenesis and activation of autoimmune diseases. The aim of this investigation was to clarify the hypothalamic-pituitary re sponse to a well-defined stimulus under standardised conditions in pat ients with SLE. Plasma concentrations of prolactin (PRL), growth hormo ne (GH) and cortisol were determined in venous blood drawn through an indwelling cannula during insulin-induced hypoglycaemia (0.1 U/kg b.w. , i.v.) in ten patients and in 12 age-, gender- and weight-matched hea lthy subjects. Basal PRL concentrations were higher in patients vs hea lthy controls (12 vs 6 ng/ml, P < 0.01), though still within the physi ological range. Insulin-induced plasma PRL and GH were significantly i ncreased both in patients and healthy subjects; however, the increment s or areas under the curves were not different in the two groups. Plas ma cortisol response showed moderate attenuation in patients. Sensitiv ity of pituitary lactotrothrops to thyrotropin-releasing hormone (TRH) administration (200 mu g, i.v.) was the same in patients and control subjects. In SLE patients with low activity of the disease the sensiti vity of pituitary PRL release to TRH administration remained unchanged . The hypothalamic response to stress stimulus (hypoglycaemia) was com parable in patients and healthy subjects.