| 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. |
