KETOGENIC AND ADIPOKINETIC ACTIVITIES OF PITUITARY HORMONES1

Abstract

The ketogenic and adipokinetic activities of a variety of samples of growth hormone (STH), TSH (thyroid stimulating hormone) and oxy-cellulose adsorbed ACTH, were tested and compared in fasted rats. On a weight basis the oxycel corticotropins were more active than STH and TSH when tested in anesthetized rats, but less so when tested in un-anesthetized rats. The ketogenic activity of ACTH in rats under Nem-butal anesthesia was 25-300 times greater than in unanesthetized animals. STH and TSH had approximately equal ketogenic activity in anesthetized and unanesthetized rats. The significance of this phenomenon is discussed. The ketogenic and adipokinetic activities of ACTH consistently resisted exposure to 0.1[image] NaOH for 16-24 hours at 25[degree]C while the re-sponse of STH was irregular. Two samples of TSH lost ketogenic activity with alkali treatment. ACTH tended to lose metabolic activity with more prolonged exposure to alkali at 25[degree] or on treatment at 100[degree]C for 10-30 minutes. Where tested, native biological activity of the ACTH and STH correlated with ketogenic activity. Analysis of results in terms of the above parameters, the biological activity of each hormone preparation and the available information concerning contamination of one hormone with another led to the conclusion that ACTH, STH and TSH each independently possess ketogenic activity, and this activity is not due to an independent ketogenic factor.