Corticotropin-releasing factor antagonist attenuates stress-induced inhibition of seasonal ovarian recrudescence in the lizard Mabuya carinata.
Whether administration of the corticotropin-releasing factor (CRF) antagonist alpha-helical CRF(9-41) (hCRF) prevents stress response of the ovary, the oviduct, the adrenals, and the spleen was studied in the lizard Mabuya carinata. Stressors (handling, chasing, and noise) applied randomly, five times a day, for 1 month to lizards during the recrudescence phase of the ovarian cycle caused a significant increase in mean nuclear diameter of the adrenal cortical cells and a significant reduction in mean number of islands of white pulp in the spleen. These results, albeit indirectly, indicated an activation of the adrenal gland and immune suppression. There was a significant decrease in the mean relative weight of the ovary and the oviduct and in the mean number of oocytes and the primordial follicles compared to those of controls. Furthermore, vitellogenic follicles were absent in the ovary of lizards exposed to stressors in contrast to their presence in controls. However, administration of hCRF to the lizards exposed to stressors (stress + hCRF) resulted in vitellogenesis and follicular growth. The mean relative weight of the ovary and the oviduct and the mean number of oocytes and the primordial follicles in stress + hCRF-treated lizards were significantly higher than those in the lizards exposed to stressors, whereas they did not significantly differ from those of controls. The results indicate that hCRF attenuates stress-induced inhibition of ovarian follicular and oviductal development in M. carinata. To the best of our knowledge, this is the first report revealing that CRF antagonist can prevent ovarian stress response in lower vertebrates.
Ganesh
C B
CB
Department of Studies in Zoology, University of Mysore, Manasagangotri, Mysore 570 006, India.
Yajurvedi
H N
HN
D000818:Animals; D003346:Corticotropin-Releasing Hormone / Q000037:antagonists & inhibitors* / Q000494:pharmacology; D005260:Female; D008116:Lizards / Q000033:anatomy & histology / Q000502:physiology*; D009929:Organ Size; D006080:Ovarian Follicle / Q000033:anatomy & histology / Q000187:drug effects; D010053:Ovary / Q000033:anatomy & histology / Q000187:drug effects / Q000502:physiology*; D010446:Peptide Fragments / Q000494:pharmacology; D012621:Seasons; D013312:Stress, Physiological
D010446:Peptide Fragments; D003346:Corticotropin-Releasing Hormone; C045089:corticotropin releasing hormone (9-41)