Wright A, Wilson J F
Peptides. 1983 Jan-Feb;4(1):5-9. doi: 10.1016/0196-9781(83)90156-0.
Pentobarbitone anesthetized rats were injected with 30 nmol (50 micrograms) alpha-MSH administered intraperitoneally (IP) and subcutaneously (SC) in an acid-saline vehicle, or SC in a zinc phosphate vehicle. Concentrations of alpha-MSH in plasma were measured by radioimmunoassay. The pharmacokinetic parameters for the three modes of administration were determined by fitting a one-compartment open model to the plasma level data. The t1/2 for absorption using the saline vehicle was 7.3 and 5.6 min from the IP and SC sites, respectively. The t1/2 for absorption from the zinc phosphate complex of 17.7 min was significantly longer. Five percent of the IP dose was absorbed into the systemic circulation giving a peak plasma level of 14.1 nmol/l. The absorption of 2-3 percent was significantly lower following SC administration; peak plasma levels were 8.3 and 4.8 nmol/l for the saline and zinc phosphate vehicles, respectively. The low percentage absorption values indicated a high degree of metabolism of the peptide by peripheral tissues on its passage from the injection sites into the circulation.
用戊巴比妥麻醉的大鼠，以酸 - 盐水载体经腹腔内（IP）和皮下（SC）注射30 nmol（50微克）α-促黑素（α-MSH），或以磷酸锌载体经皮下注射。通过放射免疫测定法测量血浆中α-MSH的浓度。通过将单室开放模型拟合到血浆水平数据来确定三种给药方式的药代动力学参数。使用盐水载体时，经腹腔和皮下部位吸收的t1/2分别为7.3分钟和5.6分钟。从磷酸锌复合物吸收的t1/2为17.7分钟，明显更长。腹腔注射剂量的5%被吸收进入体循环，血浆峰值水平为14.1 nmol/l。皮下给药后2 - 3%的吸收明显较低；盐水和磷酸锌载体的血浆峰值水平分别为8.3 nmol/l和4.8 nmol/l。低吸收百分比值表明该肽在从注射部位进入循环的过程中被外周组织高度代谢。
