In vivo effects of the steroid analogue RU486 on some aspects of intermediary and thyroid metabolism of brook charr,Salvelinus fontinalis
✍ Scribed by Vijayan, M. M. ;Leatherland, J. F.
- Publisher
- John Wiley and Sons
- Year
- 1992
- Tongue
- English
- Weight
- 730 KB
- Volume
- 263
- Category
- Article
- ISSN
- 0022-104X
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✦ Synopsis
Abstract
The glucocorticoid analogue RU486 was administered by intraperitoneal injection to brook charr (Salvelinus fontinalis) to further explore the role of cortisol on aspects of intermediary and thyroid hormone metabolism of the species.
RU486 significantly elevated the hepatosomatic index, hepatic G3PDH activity, and hepatic glycogen content, but was without effect on hepatic protein content, hepatic FPBase activity, or plasma glucose concentration. However, the stressor‐related increase in plasma glucose concentration that was evident in brook charr 24 h following handling and injection was suppressed in RU486‐treated groups.
The distribution volume, turnover rates, and metabolic clearance rates of [^3^H]cortisol were similar in RU486‐ and vehicle‐treated groups.
Plasma T~3~ and T~4~ concentrations were similar in RU486‐ and vehicle‐treated groups, but hepatic T~3~ production and hepatic T~3~ content were lower in RU486‐treated fish; TSH had no effect on hepatic T~3~ content of vehicle‐treated brook charr but significantly increased T~3~ content in the RU486‐treated group. These observations support the concept of a role of cortisol in the control of peripheral monodeiodination of T~4~ in salmonid fish and suggest that RU486 may be a useful drug for evaluating the role of cortisol in fish in vivo. © 1992 Wiley‐Liss, Inc.