Ren J M, Hultman E
Department of Clinical Chemistry II, Karolinska Institutet, Huddinge University Hospital, Sweden.
Acta Physiol Scand. 1988 May;133(1):109-14. doi: 10.1111/j.1748-1716.1988.tb08386.x.
Phosphorylase was determined in biopsy samples frozen immediately or after a delay of 10 s to 6 min. Muscle biopsies were performed at rest without and with propranolol, or adrenalin infusion and after electrical stimulation. The phosphorylase a fraction was 36% (28-44) in resting samples frozen immediately and 12% (12-13) after 10 s delay and remained at the same level when the freezing was further delayed (up to 6 min). It is suggested that an increase in [Ca2+] in the cytoplasm due to the insertion of the needle in muscle or cutting of tissue membranes may cause transformation of phosphorylase from b to a form, a transformation which is restored when Ca2+ is pumped back during the delay. Also the increased phosphorylase a fraction observed in biopsy samples obtained during adrenalin infusion reverted partially back when freezing was delayed for 10 s and 30 s, respectively. In muscle samples taken during contraction the mole fraction of phosphorylase a decreased from 53 to 12% when freezing was delayed for 10 s. The lowest value of the phosphorylase a mole fraction was observed in resting muscle after beta-blockade when the tissue samples were frozen 10 s after sampling and corresponded to 10% of the total phosphorylase. It is concluded that both muscle sampling and circulating adrenalin will increase phosphorylase a fraction in resting muscle and probably also augment the effect of adrenalin infusion.
在立即冷冻或延迟10秒至6分钟后冷冻的活检样本中测定磷酸化酶。在静息状态下，分别在未使用和使用普萘洛尔、或肾上腺素输注以及电刺激后进行肌肉活检。立即冷冻的静息样本中磷酸化酶a组分占36%（28 - 44），延迟10秒后为12%（12 - 13），当进一步延迟冷冻（长达6分钟）时保持在同一水平。这表明，由于针刺入肌肉或切割组织膜导致细胞质中[Ca2+]增加，可能会使磷酸化酶从b型转变为a型，而当在延迟期间Ca2+被泵回时，这种转变会恢复。同样，在肾上腺素输注期间获得的活检样本中观察到的磷酸化酶a组分增加，在冷冻分别延迟10秒和30秒时部分恢复。在收缩期间采集的肌肉样本中，当冷冻延迟10秒时，磷酸化酶a的摩尔分数从53%降至12%。在β受体阻滞剂作用下的静息肌肉中，当组织样本在采样后10秒冷冻时，观察到磷酸化酶a摩尔分数的最低值，相当于总磷酸化酶的10%。结论是，肌肉采样和循环中的肾上腺素都会增加静息肌肉中磷酸化酶a的组分，并且可能还会增强肾上腺素输注的效果。
