Dual activation by thyrotropin of the phospholipase C and cyclic AMP cascades in human thyroid

Mol Cell Endocrinol. 1987 Aug;52(3):273-8. doi: 10.1016/0303-7207(87)90055-4.


In human thyroid slices prelabeled with myo-[2-3H]inositol, thyrotropin (TSH, 3-30 mU/ml) stimulated IP3, IP2 and IP1 generation over a prolonged time course. The cAMP response was much more sensitive to TSH, peaking between 1 and 5 mU/ml. Forskolin (10(-5) M) and isoproterenol had no effect on basal IP levels, while carbamylcholine (10(-5) M, 10(-4) M) also increased IP accumulation. These data suggest that in the human thyroid, TSH activates a phospholipase C generating IP3 and diacylglycerol independently of the well-known adenylate cyclase stimulation. They validate in the human model a dual mode of action of the hormone previously proposed on the basis of indirect observations.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Cyclic AMP / biosynthesis*
  • Enzyme Activation / drug effects
  • Humans
  • In Vitro Techniques
  • Inositol Phosphates / metabolism
  • Kinetics
  • Thyroid Gland / drug effects*
  • Thyroid Gland / metabolism
  • Thyrotropin / pharmacology*
  • Type C Phospholipases / metabolism*


  • Inositol Phosphates
  • Thyrotropin
  • Cyclic AMP
  • Type C Phospholipases