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The behaviour of pyruvate dehydrogenase in circulating lymphocytes from diabetic children
M T Rinaudo1, M Curto, R Bruno
1Dipartimento di Medicina ed Oncologia Sperimentale-Sezione Biochimica, Università di Torino, Italy.
Insights
Juvenile diabetes significantly reduces pyruvate dehydrogenase activity in lymphocytes. Insulin therapy rapidly restores these crucial enzyme levels, highlighting its therapeutic importance.
Area of Science:
- Biochemistry
- Pediatrics
- Metabolic Disorders
Background:
- Pyruvate dehydrogenase (PDH) is a key enzyme complex regulating glucose metabolism.
- Juvenile diabetes (Type 1 diabetes) is characterized by metabolic dysregulation.
- Lymphocytes can serve as accessible cells for metabolic studies.
Purpose of the Study:
- To investigate pyruvate dehydrogenase (PDH) activity in lymphocytes of children with juvenile diabetes.
- To assess the impact of insulin therapy on PDH activity in these patients.
- To compare PDH activity in diabetic children with healthy controls.
Main Methods:
- Assaying basal and total pyruvate dehydrogenase (PDH) activities.
- Utilizing circulating lymphocytes from children with juvenile diabetes and control subjects.
- Comparing enzyme activity before and after five days of insulin therapy, and with in vitro insulin stimulation.
Main Results:
- Untreated diabetic children showed deeply decreased basal and total PDH activities with similar values.
- Control subjects exhibited basal PDH activity approximately 30% lower than total activity.
- In vivo insulin therapy normalized or increased PDH activity in diabetic patients; in vitro insulin showed a lesser stimulatory effect.
Conclusions:
- Juvenile diabetes severely impairs lymphocyte pyruvate dehydrogenase (PDH) activity.
- Insulin therapy effectively reverses this impairment, restoring PDH function.
- Lymphocyte PDH activity serves as a sensitive indicator of metabolic status in diabetes.
Abstract:
The basal and total pyruvate dehydrogenase activities were assayed in circulating lymphocytes from children with juvenile diabetes at diagnosis and after five days of insulin therapy and from control subjects. In untreated diabetic children, basal and total pyruvate dehydrogenase activities were deeply decreased and both showed very similar values; whereas, in control subjects basal activity was about 30% lower than total activity. In diabetic patients treated with insulin (in vivo situation), both basal and total activity levels were equal or even higher than those of the control subjects. The incubation of lymphocytes from diabetic patients with insulin (5 microU/ml) (in vitro situation) stimulates, but less than in vivo, the basal and total pyruvate dehydrogenase activities.