Differential induction of inositol phosphate metabolism by three adipokinetic hormones

Mol Cell Endocrinol. 1997 Jun 20;130(1-2):131-9. doi: 10.1016/s0303-7207(97)00083-x.

Abstract

Many (in)vertebrates simultaneously release several structurally and functionally related hormones; however, the relevance of this phenomenon is poorly understood. In the locust e.g. each of three adipokinetic hormones (AKHs) is capable of controlling mobilization of carbohydrate and lipid from fat body stores, but it is unclear why three AKHs coexist. We now demonstrate disparities in the signal transduction of these hormones. Massive doses of the AKHs stimulated total inositol phosphate (InsPn) production in the fat body biphasicly, but time courses were different. Inhibition of phospholipase C (PLC) resulted in attenuation of both InsPn synthesis and glycogen phosphorylase activation. The AKHs evoked differential formation of individual [3H]InsPn isomers (InsP(1-6)), the effect being most pronounced for InsP3. 40 nM of AKH-I and -III induced a substantial rise in total InsPn and [3H]InsP3 at short incubations, whereas the AKH-II effect was negligible. At a more physiological dose of 4 nM, the AKHs equally enhanced Ins(1,4,5)P3 levels. The InsP3 effect was most prolonged for AKH-III. These subtle differences in InsPn metabolism, together with earlier findings on differences between the AKHs, support the hypothesis that each AKH exerts specific biological functions in the overall syndrome of energy mobilization during flight.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Animals
  • Energy Metabolism
  • Estrenes / pharmacology
  • Fat Body / drug effects
  • Fat Body / metabolism
  • Flight, Animal
  • Grasshoppers / metabolism*
  • Inositol 1,4,5-Trisphosphate / metabolism
  • Inositol Phosphates / biosynthesis*
  • Insect Hormones / pharmacology*
  • Male
  • Phosphorylases / metabolism
  • Pyrrolidinones / pharmacology
  • Signal Transduction
  • Type C Phospholipases / antagonists & inhibitors
  • Type C Phospholipases / metabolism

Substances

  • Estrenes
  • Inositol Phosphates
  • Insect Hormones
  • Pyrrolidinones
  • 1-(6-((3-methoxyestra-1,3,5(10)-trien-17-yl)amino)hexyl)-1H-pyrrole-2,5-dione
  • adipokinetic hormone (locust)
  • Inositol 1,4,5-Trisphosphate
  • Phosphorylases
  • Type C Phospholipases