Systemic and pituitary pars intermedia antioxidant capacity associated with pars intermedia oxidative stress and dysfunction in horses.

The research investigates whether a deficiency in the body’s antioxidant capacity is linked with the oxidative stress and dysfunction of the pituitary pars intermedia, specifically in the instance of horses suffering from pituitary pars intermedia dysfunction (PPID). The findings show no significant evidence of systemic accumulation of oxidative stress or antioxidant deficiencies contributing to the development of PPID. However, it was observed that a particular antioxidant enzyme, Manganese superoxide dismutase, decreased with age in the pituitary pars intermedia.

Research Subject and Methodology

• The focus of the study was to determine if there’s a correlation between a deficiency in the antioxidant capacity of the body or the pituitary pars intermedia (a part of the pituitary gland), and the development of pituitary pars intermedia dysfunction (PPID) in horses.
• A sample set of 40 horses were involved in the research, 20 with diagnosed PPID and 20 healthy ones. The study also included an analysis of stored adrenal gland and substantia nigra tissues from 20 horses, along with pituitary gland tissue from 16 horses.
• To evaluate their antioxidant capacity, the researchers assessed total glutathione, superoxide dismutase, and glutathione peroxidase activities in their red blood cells. An additional systemic marker of oxidative stress (3-nitrotyrosine) was examined in horses’ blood plasma, and adrenal gland and substantia nigra tissues.

Results of the Study

• The results showed no significant disparities in systemic antioxidant enzyme activity or accumulation of 3-nitrotyrosine between horses with PPID and control horses.
• In the pituitary gland tissues, glutathione peroxidase activity was elevated in horses with oxidative stress, but there was no change in total glutathione concentration and superoxide dismutase activity.
• An age-related decrease was observed in the activity of an antioxidant enzyme, Manganese superoxide dismutase, in the pars intermedia.

Conclusions and Further Studies

• The data suggests there’s no significant evidence that points towards systemic oxidative stress accumulation or antioxidant capacity deficiencies playing a pivotal role in the onset of PPID in horses.
• Nonetheless, it was discovered that Manganese superoxide dismutase activity in the pars intermedia significantly dropped with age. Consequently, further research is recommended to better understand the implications of this observation in relation to the development of PPID in horses.