**Background**
Insect juvenile hormones play a critical role in regulating the development and metamorphosis of insects, specifically by controlling the transition between larval, pupal, and adult stages. Disrupting these hormonal pathways is a primary strategy in the development of effective insecticides to control agricultural pests and disease vectors. Beyond entomology, recent pharmacological research has identified unexpected interactions between certain hormone analogs and mammalian G-protein coupled receptors. Specifically, the cannabinoid receptor type 1 (CB1) is a key target in the central nervous system and peripheral tissues, making the discovery of novel ligands essential for understanding receptor modulation. In this context, we will introduce an insect juvenile hormone analog that also acts as a CB1 receptor ligand – S-Methoprene.
**Definition**
S-Methoprene is an insect juvenile hormone analog and effective insecticide that blocks the transition from pupa to adult, which also functions as a CB1 receptor ligand with a Ki of 2.13 μM.
**In Vitro and In Vivo Studies**
According to the S-Methoprene description, this compound possesses a molecular weight of 310.47 and the S-Methoprene formula is C19H34O3. In terms of S-Methoprene biological activity, the compound has been utilized as a larvicide and to accelerate sexual maturation in male Queensland Fruit Flies (Diptera: Tephritidae). In vitro studies focusing on the CB1 receptor demonstrated that S-Methoprene inhibits the binding of the CB1 receptor antagonist [3H]CP-55940 to the CB1 receptor with an IC50 of 19.31 μM. Specifically, S-Methoprene (4 μM) inhibited [3H]CP-55940 binding by 27.32± 4.11% and 28.16± 4.17% in the absence and presence of 50 μM PMSF, respectively, in mouse meninges. Furthermore, S-Methoprene was found to inhibit CP-55940-stimulated binding of [35S]GTPγS to mouse meninges, demonstrating a concentration-dependent inhibition of CB1 receptor binding. In conclusion, S-Methoprene is a versatile compound that serves as both a potent insect growth regulator and a ligand for the mammalian CB1 receptor.
Keywords
S-Methoprene, 65733-16-6, (+)-Methoprene, (7S)-Methoprene, Cannabinoid Receptor, CB1 receptor, Sanguinarine, Chelerythrine, Piperonyl butoxide, Methoprene, Mouse brain, Inhibitor, inhibitor, inhibit
References
[1] Adnan SM, et al. Accelerated Sexual Maturation in Methoprene-Treated Sterile and Fertile Male Queensland Fruit Flies (Diptera: Tephritidae), and Mosquito Larvicide as an Economical and Effective Source of Methoprene. J Econ Entomol. 2019 Dec 9;112(6):2842-2849.
[2] Dhopeshwarkar AS, et al. The actions of benzophenanthridine alkaloids, piperonyl butoxide and (S)-methoprene at the G-protein coupled cannabinoid CB₁ receptor in vitro. Eur J Pharmacol. 2011 Mar 1;654(1):26-32.