RESUMEN
Corticotropin-releasing hormone (CRH) levels in the human plasma and cerebrospinal fluid (CSF), and those in the rat hypothalamus, peripheral and hypophyseal portal plasma were studied by a specific h/r CRH RIA and an immunoaffinity procedure. CRH levels in the plasma and CSF were low in patients with hypercortisolemia and those with hypothalamic hypopituitarism, but high in patients with hypocortisolemia except for patients with hypothalamic hypopituitarism. Plasma CRH responded to insulin-induced hypoglycemia (ITT) those with Addison's disease and those with primary hypopituitarism, but not in patients with Cushing's syndrome or in patients with hypothalamic hypopituitarism. The results suggest that the major component of plasma CRH may be of hypothalamic origin, but other extrahypothalamic tissues cannot be ruled out as minor sources of plasma CRH. In addition, the measurement of CRH levels in the plasma and CSF seems to be of value in evaluating the hypothalamic function. The short negative feedback mechanism regulating CRH release was demonstrated in humans and rats. In the absence of the long negative feedback control of ACTH secretion by glucocorticoids, ACTH originating from the pituitary may regulate ACTH secretion form the pituitary through inhibition of CRH release.
Asunto(s)
Hormona Liberadora de Corticotropina/análisis , Enfermedad de Addison/sangre , Enfermedad de Addison/líquido cefalorraquídeo , Enfermedad de Addison/metabolismo , Animales , Hormona Liberadora de Corticotropina/sangre , Hormona Liberadora de Corticotropina/líquido cefalorraquídeo , Síndrome de Cushing/sangre , Síndrome de Cushing/líquido cefalorraquídeo , Síndrome de Cushing/metabolismo , Humanos , Hipopituitarismo/sangre , Hipopituitarismo/líquido cefalorraquídeo , Hipopituitarismo/metabolismo , Hipotálamo/análisis , Hipotálamo/metabolismo , Inmunoensayo , Síndrome de Nelson/sangre , Síndrome de Nelson/líquido cefalorraquídeo , Síndrome de Nelson/metabolismo , Hipófisis/análisis , Hipófisis/metabolismo , Radioinmunoensayo , Ratas , Valores de Referencia , Distribución TisularRESUMEN
Our findings to date indicate that: A peptide resembling oCRF is present in human and mammalian hypothalamus. oCRF is present in human lumbar cerebrospinal fluid. oCRF concentrations do not differ in CSF from normal individuals and from patients with Cushing's syndrome. oCRF appears to be synthesized via a large oligopeptide precursor. An oCRF-like molecule (oCRF-LI) is present in hypothalamic brain tissue. We have also observed more tentative evidence of low levels of oCRF-LI outside of the brain. oCRF is likely to be a central mediator of stress in its multiple forms. We believe that oCRF is clearly of major physiological importance, but that many critical unanswered questions remain. Probably, the most fascinating of these, which we are only beginning to comprehend, concerns the functions of CRF in extrahypothalamic brain as well as the CRF which appears to be present outside the brain.