The role of endozepine in the regulation of steroid synthesis.
Endozepine has recently been isolated from various steroid-forming organs. The following article explores the role of endozepine in the regulation of steroid synthesis. Steroid hormone synthesis from cholesterol begins in the inner mitochondrial membrane, where cytochrome P450 converts cholesterol to pregnenolone. Scientists thought that ACTH would stimulate this conversion, but experiments showed no such stimulation. However, addition of aminoglutethimide to block side-chain cleavage caused the expected reaction of ACTH to take place. Next the role of protein synthesis on the actions of ACTH was explored. Then endozepine was isolated from bovine fasciculata based on stimulation of pregnenolone production by freshly prepared mitochondria. After further experimentation it was concluded that endozepine is a peptide with at least two groups of actions: It binds GABAA receptors in the central nervous system, and it increases the mitochondrial synthesis of pregnenolone.
Hall
P F
PF
Department of Endocrinology, Prince of Wales Hospital, Randwick, NSW, Australia.
D000324:Adrenocorticotropic Hormone / Q000502:physiology; D000818:Animals; D002352:Carrier Proteins / Q000502:physiology*; D003577:Cytochrome P-450 Enzyme System / Q000378:metabolism; D026261:Diazepam Binding Inhibitor; D006728:Hormones / Q000096:biosynthesis*; D006801:Humans; D008928:Mitochondria / Q000378:metabolism; D011284:Pregnenolone / Q000096:biosynthesis; D011963:Receptors, GABA-A / Q000502:physiology; D013256:Steroids / Q000096:biosynthesis*; D013261:Sterols / Q000378:metabolism
D002352:Carrier Proteins; D026261:Diazepam Binding Inhibitor; D006728:Hormones; D011963:Receptors, GABA-A; D013256:Steroids; D013261:Sterols; D011284:Pregnenolone; D000324:Adrenocorticotropic Hormone; D003577:Cytochrome P-450 Enzyme System