This study was undertaken to investigate whether the developing brain adapts at biochemical level against neonatal hypothyroidism, as it does so against a variety of physiological disturbances. A moderate hypothyroid state in mice neonates was induced by supplementing 0.05% methimazole in drinking water to the mothers up to suckling period, and its effect on concerted development of the enzymes regulating metabolic channeling of glucose vis a vis glucose phosphorylating activity were studied. In the brain of control mice, the activity of glucose-6-phosphate dehydrogenase (G6PDH), that channels glucose in biosynthetic route (Pentose phosphate pathway, PPP), increased slightly (∼ 1.3 times) from day1 to 10w age. However, glucose phosphorylating activity and the enzymes that commit glucose for energy production, viz phosphofructokinase1 (PFK1), pyruvate kinase (PK) and lactate dehydrogenase (LDH) showed a progressive postnatal increase to attain their respective adult levels (∼ 5-10 times higher than 1day value) by 3-10w ages of mice. In comparison to the control, in the brain of age matched neonatal hypothyroid mice, glucose phosphorylating activity, G6PDH and PFK1 increased significantly (p<0.001) at day1. Thereafter, though, glucose phosphorylating activity continued to increase up to 1w age and remained static thereafter, G6PDH declined significantly (p<0.001) from 1w onward ages. On the other hand, as PFK1 activity increased significantly up to 10w age (p<0.001), the ratio of G6PDH/PFK1 showed a marked decline from 1w onward ages. PK and LDH also showed increasing trend up to 3w age in the brain of hypothyroid mice pups. The results suggest that a moderate hypothyroid state, during the period of rapid brain growth (day 1-1w age), stimulates all the enzymes that regulate channeling of glucose in both, the energy yielding and biosynthetic paths. However, the later postnatal ages, it modulates these enzymes in a metabolic path dependent manner.
| Identifer | oai:union.ndltd.org:ETSU/oai:dc.etsu.edu:etsu-works-19596 |
| Date | 01 December 2005 |
| Creators | Pandey, P., Singh, S. K., Trigun, S. K. |
| Publisher | Digital Commons @ East Tennessee State University |
| Source Sets | East Tennessee State University |
| Detected Language | English |
| Type | text |
| Source | ETSU Faculty Works |
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