Effects of corticosterone treatment and wound healing on reproductive traits of American bullfrogs.
J Exp Zool A Ecol Integr Physiol
; 335(2): 275-285, 2021 02.
Article
in En
| MEDLINE
| ID: mdl-33411410
During reproductive season, calling anuran males display high testosterone (T) and episodically high corticosterone (CORT) plasma levels, which are positively associated with higher calling rates and immunocompetence. However, exposure to constant stress stimuli can result in chronically elevated CORT levels, possibly leading to inhibition of reproductive and immune activity. Reproduction and immune responses are energetically expensive, so when an animal is immunologically challenged, a tradeoff might be expressed, with CORT potentially mediating it. Our aim was to test how episodic and chronic CORT treatments, alongside wound healing, would affect reproduction in American bullfrog males (Lithobates catesbeianus). Forty animals were divided in four groups: Episodic CORT (daily transdermic application of CORT), placebo (daily transdermic application of sesame oil), chronic CORT (subcutaneous CORT silastic implants), and sham control (subcutaneous empty silastic implants). One week after treatments began, animals were punctured in the leg with a biopsy needle and the wound was photographed after 45 days to determine wound healing status (WS). Blood samples were collected throughout the experiment to measure CORT and T plasma levels. After animal euthanasia, testes were dissected, fixed, and analyzed histologically to determine spermatogenic activity (germinative cyst [GmC] morphometrics). As expected, the episodic CORT treatment had no effect on T plasma levels or spermatogenic activity. On the other hand, chronic CORT treatment reduced GmC morphometric traits, indicating suppression of reproduction, although T levels were not altered. In addition, animals from sham control and chronic CORT treatments with higher T levels presented higher WS, which indicates an immune-enhancing T effect.
Key words
Full text:
1
Collection:
01-internacional
Database:
MEDLINE
Main subject:
Rana catesbeiana
/
Sexual Behavior, Animal
/
Wound Healing
/
Corticosterone
/
Anti-Inflammatory Agents
Limits:
Animals
Language:
En
Journal:
J Exp Zool A Ecol Integr Physiol
Year:
2021
Document type:
Article
Affiliation country:
Brazil
Country of publication:
United States