[Validation of the radioimmunoassay for rat luteinizing hormone (LH) (author's transl)]

A rat LH radioimmunoassay (RIA) using the immunoreactants provided by Dr Parlow on behalf of the Rat Pituitary Hormone Program of the NIAMDD of the NIH is described. The instructions suggested by the NIH have been modified in order to reach a higher sensitivity. It is possible to use prepipetted frozen standards and the same labelled antigen over a period of 1 month, or longer, after labelling, provided the preparation is purified immediately prior to its use. These procedures, as well as the addition of antibody and buffer simultaneously, shorten considerably the time spent on a given RIA and decrease the inter- and intra-assay variability. The specificity of the method is also described. There is good parallelism between the standard curve and serial dilutions of plasmas and hypophyses of rats. The RIA was validated physiologically by LH determination on plasmas obtained from animals submitted to different experimental situations in which a decrease (hypophysectomy) or increase (ovariectomy, LH-RH treatment, etc.) of this hormone is expected.