[Studies on endogenous LHRH].

There has been increasing the evidence on the significances of the measurements of LHRH, one of the hypothalamic hormones, but there are no report on endogenous LHRH levels in patients with internal diseases associated with gonadal dysfunction or intracranial diseases. In this report, the radioimmunoassay of LHRH was established, and plasma LHRH levels in chronic renal failure before and during haemodialysis, and the levels in cerebrospinal fluid (CSF) and plasma in patients with acute intracranial diseases were determined. Plasma levels of immunoreactive LHRH in healthy adults were less than 7 pg/ml for men (n = 17) and less than 8 pg/ml for women (n = 25). The levels were increased in women in menstrual midcycle, postmenopausal period or in patients with hypergonadotropic hypogonadism. CSF LHRH levels were less than 6.1 pg/ml in control subjects, and there were no difference between postmenopausal subjects and the others. The immunoreactivities of CSF and plasma extracts were eluted in identical fractions with synthetic LHRH on Sephadex G-25 chromatography, and these dilutions gave a displacement curve parallel to that with the standard. Plasma LHRH levels were increased in patients with chronic renal failure before haemodialysis (11.1 +/- 1.4 pg/ml, mean +/- SE), and the levels were declined after the dialysis to 4.8 +/- 0.5 pg/ml. These suggest that elevated plasma LHRH reflects the decreased feedback inhibition by primary gonadal failure, and might in turn be responsible at least in part for high concentrations of plasma LH in this condition, and that plasma LHRH is mainly not bound to plasma proteins. LHRH levels of CSF and plasma in patients with acute intracranial diseases, e.g. cerebral bleeding, cerebral thrombosis and meningitis were often elevated abnormally, and these levels were decreased following the abatement of the diseases. These elevations are supposed to be the non-specific changes of this brain peptide suggesting the leakage from the damaged brain, but further studies are needed to clarify these potential significances.