Effect of hypothyroidism on the NO/cGMP pathway of corpus cavernosum in rabbits
Date
2006-09
Authors
Bahçıvan, İhsan
Yıldırım, M. Kemal
Saraç, Bülent
Kaya, Tijen
Journal Title
Journal ISSN
Volume Title
Publisher
Elsevier
Abstract
Introduction. The incidence of hormonal dysfunction as a cause of impotence remains controversial. However, several recent studies have reported evidence of hormonal abnormalities in 25-35% of impotent men. Hypothyroidism has been reported to occur in 6% of impotent men. There is some evidence suggesting that hypothyroidism may be a cause of impotence. Aim. We aimed to investigate the nitric oxide (NO)/cyclic guanosine monophosphate (cGMP) pathway in hypothyroidism in an experimental rabbit model and compared hypothyroid rabbits with controls to evaluate the possible involvement of the NO/cGMP pathway. Methods. The study comprised 20 male New Zealand white rabbits. The rabbits were divided into two equal groups. The first group had hypothyroidism induced surgically by thyroidectomy for 6 weeks. The second group underwent a sham operation. Results. There was no significant change in the mean body weight of hypothyroid rabbits and controls. Triiodothyronine and thyroxine levels were significantly lower in hypothyroid rabbits. Plasma thyroid-stimulating hormone and prolactin levels were significantly higher in hypothyroid rabbits. Plasma total calcium and parathormone levels remained in the normal range in both groups. Main Outcome Measures. Papaverine-induced concentration-dependent relaxations were similar in both groups. Carbachol-induced relaxation responses decreased in hypothyroid rabbits. There were significant differences between control and hypothyroid rabbits in frequency-dependent relaxations induced by electrical-field stimulation (EFS). YC-1-induced relaxation responses did not change significantly in hypothyroid rabbits. Concentration-dependent relaxations induced by diethylamine (DEA)/NO were similar in both groups. Amrinone-induced relaxation responses did not change significantly in hypothyroid rabbits. Conclusion. Reductions of relaxant responses to EFS and carbachol in hypothyroid rabbits can depend on the decrease of released or synthesized NO from nitrergic nerves and endothelium.
Description
Keywords
Urology & nephrology, Animal models, Endocrinologic studies of sexual function, Pharmacologic studies in sexual function, Relaxation, YC-1, Synergistic activation, Noncholinergic neurotransmission, Penile erection, Nitric-oxide, Tissue in-vitro, Smooth-muscle tone, Cyclic-nucleotide phosphodiesterase, Soluble guanylyl cyclase
Citation
Kılıçarslan, H. vd. (2006). ''Effect of hypothyroidism on the NO/cGMP pathway of corpus cavernosum in rabbits''. Journal of Sexual Medicine, 3(5), 830-837.