glutathione is a protein Reductase, Human Recombinant Redox Regulation by Protein S-Glutathionylation:

C.PalzkillT

Activated ATF4 could transcribe System Xc-, promote GSH expression to elevate antioxidant capacity, and inhibit cellular ferroptosis, whereas knockdown of ATF4 caused ROS accumulation, inducing ferroptosis

Improved survival from acute renal failure after treatment with intravenous essential L-amino acids and glucose

Biochem Biophys Res Commun 228:579585 Paulusma CC, van Geer MA, Evers R, Heijn M, Ottenhoff R, Borst P, Oude Elferink RP (1999) Canalicular multispecific organic anion transporter/multidrug resistance protein 2 mediates low-affinity transport of reduced glutathione

GSSG is then reduced to GSH by glutathione reductase (GR) using reducing equivalent provided by NADPH