The genetically obese mouse (obob): the role of hypothyroidism in adipose tissue metabolism and energy balance
The genetically obese mouse (obob): the role of hypothyroidism in adipose tissue metabolism and energy balance
In vivo uptake of 1311 by thyroids of obob mice was reduced from 1-6 months, and not improved by adrenalectomy or pair-feeding. Serum Thyroxine (T4) was low at 1 month. Serum Triiodothyronine (T3) was low at 6 months. T3 in GTG (static) obese mice was high; T4 was normal. T3 injections suppressed T4 production in lean and obob mice. T3 injections raised heat production (HP) of obob mice (per kg0'75), but took longer than GTG (static) obese mice.The sensitivity of gonadal fat pad pieces to adrenaline (/Amol glycerol/ 106cells/hour) was reduced in obob mice, but rose with T3 injections. The T3 dose and the time for effect were greater in obob than lean mice. GTG (static) obese mice were intermediate. T3 did not enhance obob lipolysis at 50pg/ml adrenaline, although cell-associated FA were not inhibitory. Pat cells of lean, hypothyroid lean, and obob mice did not possess o(-adrenergic activity.The body composition of adult obob mice was improved by T3-treatment, and protein accretion rose 6-fold. The energy requirement for maintenance (Em) was estimated by regressing carcass energy change against digestible energy intake (DEI) in 7-10 week lean, obob and GTG (dynamic) obese mice, and was 53 ± 2 kJ/d/animal. Over a range of DEI (55-73kJ/d) lean mice lost excess calories' as' heat. GTG (dynamic) and obob mice showed no such control. Dietary-induced the rihogenesis (DIT) was reduced in obob mice and suppressed in GTG (dynamic) obese mice.Conclusions: 1. obob mice have impaired thyroid function and reduced peripheral responsiveness to T4 and T3 from 1 month; 2. T3-treatment improves body composition, HP, and adipose tissue sensitivity to catecholamines in obob mice; 3. obesity in obob and GTG mice is not influenced by low Em, but reduced DIT favours storage of energy.
University of Southampton
Otto, William Richard
a4561a38-07f5-47ff-b481-59b4b877315b
1977
Otto, William Richard
a4561a38-07f5-47ff-b481-59b4b877315b
Otto, William Richard
(1977)
The genetically obese mouse (obob): the role of hypothyroidism in adipose tissue metabolism and energy balance.
University of Southampton, Doctoral Thesis.
Record type:
Thesis
(Doctoral)
Abstract
In vivo uptake of 1311 by thyroids of obob mice was reduced from 1-6 months, and not improved by adrenalectomy or pair-feeding. Serum Thyroxine (T4) was low at 1 month. Serum Triiodothyronine (T3) was low at 6 months. T3 in GTG (static) obese mice was high; T4 was normal. T3 injections suppressed T4 production in lean and obob mice. T3 injections raised heat production (HP) of obob mice (per kg0'75), but took longer than GTG (static) obese mice.The sensitivity of gonadal fat pad pieces to adrenaline (/Amol glycerol/ 106cells/hour) was reduced in obob mice, but rose with T3 injections. The T3 dose and the time for effect were greater in obob than lean mice. GTG (static) obese mice were intermediate. T3 did not enhance obob lipolysis at 50pg/ml adrenaline, although cell-associated FA were not inhibitory. Pat cells of lean, hypothyroid lean, and obob mice did not possess o(-adrenergic activity.The body composition of adult obob mice was improved by T3-treatment, and protein accretion rose 6-fold. The energy requirement for maintenance (Em) was estimated by regressing carcass energy change against digestible energy intake (DEI) in 7-10 week lean, obob and GTG (dynamic) obese mice, and was 53 ± 2 kJ/d/animal. Over a range of DEI (55-73kJ/d) lean mice lost excess calories' as' heat. GTG (dynamic) and obob mice showed no such control. Dietary-induced the rihogenesis (DIT) was reduced in obob mice and suppressed in GTG (dynamic) obese mice.Conclusions: 1. obob mice have impaired thyroid function and reduced peripheral responsiveness to T4 and T3 from 1 month; 2. T3-treatment improves body composition, HP, and adipose tissue sensitivity to catecholamines in obob mice; 3. obesity in obob and GTG mice is not influenced by low Em, but reduced DIT favours storage of energy.
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Published date: 1977
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Local EPrints ID: 462683
URI: http://eprints.soton.ac.uk/id/eprint/462683
PURE UUID: 3e506b19-e86d-40a0-aa1e-6b5a6235d23c
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Date deposited: 04 Jul 2022 19:40
Last modified: 23 Jul 2022 01:08
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Author:
William Richard Otto
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