Transient increase in prostaglandin production as an acute response of thyroid isolated follicles to thyrotropin

Abstract

1. Isolated follicles obtained from pig thyroid were incubated in Krebs-Ringer bicarbonate buffer containing glucose. Following an immediate increase, immunoreactive prostaglandin E in the reaction system reached a plateau. When 80 mU/ml of thyrotropin was added 30 min after the onset of incubation, the prostaglandins abruptly increased within 1 min and returned to the original level by 10 min, while no appreciable change was observed in the absence of TSH. 2. The minimal effective dose of TSH for this induction of prostaglandin increase was between 1 and 5 mU/ml under the present conditions. 3. The specificity of the stimulant was tested by using the same number of units of two thyrotropin preparations and the same weight of other hormones. ACTH was not active. Lutropin and follitropin were considerably less active than, and epinephrine was as active as, thyrotropin. 4. The phenomenon may reflect the TSH-induced transient accumulation of diacylglycerol (B.B.R.C. 97, 759 and 765) as a possible source of prostaglandins.