Biochemical SocietyTransactions ( 1 992) 20
Glucose utilization by skeletal muscle during pregnancy
HOLNESS, M.J. & BENTLEY, J. Department of Biochemist Basic Medical Sciences, Queen Ma & Westfield Cogge, Mile End Road, London E l 4NS, U x . The necessity to accommodate the developmental and fuel requirements of the conce tus confers a considerable nutritional burden on the mot er. Substantial changes in maternal metabolism therefore occur during late pregnancy, including hvoglycaemia [ 1-31, increased glucose turnover [4,5] and insulin resistance [6-81. A comparison of glucose utilization in skeletal muscles of 19 day pregnant rats and age-matched virgin controls failed to observe significant suppression, exce t in the extensor digitorum longus [9]. This is a non-worfing muscle comprising a high proportion of glycol ic fibres [ 101. However, the study was conducted in anaest etized rats and anaesthesia is known to sup ress lucose utilization by working skeletal muscles [ l l . We fierefore investi ated the effects of pregnancy on ske eta1 muscle glucose uti ization in conscious rats. Age-matched female albino Wistar rats were maintained on a 12 h light/l2 h dark cycle (light from 1O:OO h). Pregnant rats were sampled at 10, 15 or 20 days of pregnan , the stage of pregnancy being determined as describeTin [ 121. Body wts. at 10, 15 and 20 d of pregnancy were 246 f log, 278 f 5g and 339 f 8g respectively: mean body wts. of age-matched virgin controls were 245 & 8g. The average number of foetuses per pregnant rat was 13 (range 9 to 20). Glucose utilization indices (GUI values) and blood glucose concentrations were determined as in ~31.
1
f
f
s
197s
utilization was observed after 20 days of regnancy i.e. immediately before term at 21 days. At t k s time GUI values were decreased by 58% in soleus and ADL, and by 73% in the diaphra Leturque et aL &86) [9] have suggested that the lower rates of glucose utilization by adductor longus observed after 19 days of gestation mght reflect the lower blood glucose concentrations observed during late pre ancy. In the present series of experiments, blooc$ p c o s e concentrations were decreased by 42% after 20 ays of pregnancy (virgin rats, 5.81 f 0.23 mM blood glucose; 20 da regnant rats, 3.37 0.10 mM blood glucose; P
Glucose utilization by skeletal muscle during pregnancy
HOLNESS, M.J. & BENTLEY, J. Department of Biochemist Basic Medical Sciences, Queen Ma & Westfield Cogge, Mile End Road, London E l 4NS, U x . The necessity to accommodate the developmental and fuel requirements of the conce tus confers a considerable nutritional burden on the mot er. Substantial changes in maternal metabolism therefore occur during late pregnancy, including hvoglycaemia [ 1-31, increased glucose turnover [4,5] and insulin resistance [6-81. A comparison of glucose utilization in skeletal muscles of 19 day pregnant rats and age-matched virgin controls failed to observe significant suppression, exce t in the extensor digitorum longus [9]. This is a non-worfing muscle comprising a high proportion of glycol ic fibres [ 101. However, the study was conducted in anaest etized rats and anaesthesia is known to sup ress lucose utilization by working skeletal muscles [ l l . We fierefore investi ated the effects of pregnancy on ske eta1 muscle glucose uti ization in conscious rats. Age-matched female albino Wistar rats were maintained on a 12 h light/l2 h dark cycle (light from 1O:OO h). Pregnant rats were sampled at 10, 15 or 20 days of pregnan , the stage of pregnancy being determined as describeTin [ 121. Body wts. at 10, 15 and 20 d of pregnancy were 246 f log, 278 f 5g and 339 f 8g respectively: mean body wts. of age-matched virgin controls were 245 & 8g. The average number of foetuses per pregnant rat was 13 (range 9 to 20). Glucose utilization indices (GUI values) and blood glucose concentrations were determined as in ~31.
1
f
f
s
197s
utilization was observed after 20 days of regnancy i.e. immediately before term at 21 days. At t k s time GUI values were decreased by 58% in soleus and ADL, and by 73% in the diaphra Leturque et aL &86) [9] have suggested that the lower rates of glucose utilization by adductor longus observed after 19 days of gestation mght reflect the lower blood glucose concentrations observed during late pre ancy. In the present series of experiments, blooc$ p c o s e concentrations were decreased by 42% after 20 ays of pregnancy (virgin rats, 5.81 f 0.23 mM blood glucose; 20 da regnant rats, 3.37 0.10 mM blood glucose; P
