Immunohistochemical and histochemical studies of pituitary β‐lipotrophs

Abstract

Abstract The presence of β‐lipotrophin or an immunologically similar substance was demonstrated in the intermediate lobe cells and some basophils of the anterior lobe by both fluorescent and peroxidase‐conjugated antibody methods. These basophils were found to be corticotrophs, i.e., reactive with anti‐ACTH. ACTH, when added to anti‐β‐LPH, decreased the fluorescence and peroxidase reactions of intermediate lobe cells and the anterior lobe corticotrophs. The addition of MSH to anti‐β‐LPH produced a slight decrease in the reaction between the intermediate lobe cells and anti‐β‐LPH. The intermediate lobe cells also reacted with anti‐ACTH. Both Somatotrophs and lactotrophs reacted with anti‐β‐LPH to give positive fluorescence or peroxidase reactions. However, the addition of STH to anti‐β‐LPH abolished the reaction between anti‐β‐LPH and somatotrophs. Similarly, LTH, when added to anti‐β‐LPH, abolished the positive reaction of lactotrophs to anti‐β‐LPH. When STH, LTH and ACTH were added to anti‐β‐LPH, the fluorescence of the somatotrophs and lactotrophs was abolished, whereas the corticotrophs maintained their fluorescence at a reduced intensity. These results indicate that the somatotrophs and lactotrophs do not contain β‐LPH and that corticotrophs contain β‐LPH.