Related Experiment Video
Updated: Jul 8, 2026

Measurement of Cyclic Guanosine Monophosphate (cGMP) in Solid Tissues using Competitive Enzyme-Linked Immunosorbent Assay (ELISA)
Published on: July 3, 2025
Effect of hemin and carbon monoxide releasing molecule (CORM-3) on cGMP in rat penile tissue
M Talaat Abdel Aziz1, M Farid El-Asmar, Taymour Mostafa
1Molecular Biology Unit, Medical Biochemistry Department, Faculty of Medicine, Cairo University, Cairo, Egypt.
Introduction:
Cyclic guanosine monophosphate (cGMP) levels can be regulated by heme oxygenase-1 and 2 (HO-1 and HO-2)-derived carbon monoxide (CO).
Aims:
Assessment of the effect of upregulating CO in rat corpora cavernosa (CC) on cavernous cGMP.
Methods:
Three experimental groups were studied: first group (N = 40), short-term HO induction over 2 weeks by injection of intraperitoneal increasing doses of hemin; the second group (N = 40) was subjected to intracavernosal injection of CO donor, CORM-3, or its inactive form (iCORM-3) over 2 weeks; the third group (N = 60) was subdivided into three subgroups: the first one received a combined hemin and CORM-3, the second one received hemin and its inhibitor stannus mesoporphyrin (SnMP), and third one received a combined hemin, CORM-3, and SnMP.
Main Outcome Measures:
In CC, HO-1 and HO-2 gene expression, Northern blot and Western blot, cGMP levels, and HO enzyme activity.
Results:
In the first group, maximum induction of HO-1 gene expression, HO enzyme activity, and cGMP occurred with 4-mg hemin dose with a successive increase over 2 weeks. In the second group, CORM-3 increased cGMP by twofold compared with iCORM-3, and also increased HO-1 protein. In the third group, SnMP inhibited the enhancing effect of CORM-3 and HO on erectile signaling molecules; i.e., HO-1 gene, enzyme activity, and cGMP.
Conclusions:
CORM-3- or hemin-mediated CO release could increase cavernous tissue cGMP.
Related Concept Videos
Nitric Oxide Signaling Pathway
Treatment for Pulmonary Arterial Hypertension: Phosphodiesterase Inhibitors
Among the PDE5 inhibitors, sildenafil (Revatio) stands out as a competitive and selective inhibitor. It operates by elevating cellular levels of cGMP and augmenting signaling through the cGMP-PKG pathway, promoting vasodilation. Upon oral...
GPCRs Regulate Adenylyl Cylase Activity
Two...
