STUDIES ON ULTRACENTRIFUGE FRACTIONS OF ANTERIOR PITUITARY WITH SPECIAL REFERENCE TO ADRENOCORTICOTROPHIC HORMONE1

Publisher Website
Google Scholar
Abstract
Subcellular fractions from the anterior pituitary lobe obtained by ultracentrifugation were analyzed for purity by chemical, enzymatic, and physical tests. After separation of particles was established each fraction was analyzed by a three-dose response method for the hormones present. The hormones of the anterior pituitary occur in separate-subcellular fragments; LH and STH in the secretory granules, TSH in the mitochondria, and ACTH in the microsomes and supernatant. FSH in scattered over several fractions. Treatment of the fractions with acid has little effect on STH while alkali destroys this hormone. TSH activity is destroyed by both acid and alkaline treatment. Acid treatment of the fractions augments FSH activity while it destroys LH activity. Alkaline treatment decreases the activity of the gonadotrophins. ACTH activity is potentiated by acid treatment, while alkaline treatment decreases the activity of ACTH slightly. Analysis of the fractions for hormone content indicates that ACTH comprises 1%, STH 0.6%, TSH 1.8%, FSH 1.1% and LH 1.4% of the weight of whole fresh anterior pituitary. On the basis of unitage there were 11 units of ACTH, 6 units STH, 720 units of TSH, 550 units of FSH and 350 units of LH per gm. of fresh pituitary and 6 times these amounts per gram of pituitary proteins.