Fiser R H, Fisher D A, Williams P R, Sperling M A, Oh W
Am J Obstet Gynecol. 1976 Feb 15;124(4):421-4. doi: 10.1016/0002-9378(76)90104-6.
Plasma concentrations of glucose, alanine, and glucagon were measured after 24 hour fasting in newborn and infant sheep and in response to infusion of alanine alone and concurrently with theophylline. The plasma glucagon response to alanine was minimal in newborn sheep; in contrast, alanine produced a brisk response in plasma glucagon concentration in infant sheep. Glucose concentrations were unchanged in both groups. Theophylline enhanced blood glucagon and glucose responses to alanine in newborn animals but had minimal effects on the response of the infant sheep. These data, considered with earlier data in fetal sheep, suggest a progressive maturation of pancreatic islet alpha-cell glucagon secretion in the sheep during the postnatal period and suggest that the blunted glucagon response observed in the neonate is related to immaturity of the glucagon secretion mechanisms rather than deficient synthesis of the hormone. This immaturity may be related to impaired synthesis and/or enhanced degradation of cyclic adenosine monophosphate (cAMP) or to diminished responsiveness to cAMP.
在新生和幼年绵羊禁食24小时后，以及单独输注丙氨酸和同时输注丙氨酸与茶碱后，测量了血浆中葡萄糖、丙氨酸和胰高血糖素的浓度。新生绵羊对丙氨酸的血浆胰高血糖素反应最小；相反，丙氨酸在幼年绵羊中引起血浆胰高血糖素浓度的快速反应。两组的葡萄糖浓度均未改变。茶碱增强了新生动物血液中胰高血糖素和葡萄糖对丙氨酸的反应，但对幼年绵羊的反应影响最小。这些数据与早期关于胎羊的数据一起考虑，表明绵羊出生后胰腺胰岛α细胞胰高血糖素分泌逐渐成熟，并表明新生儿中观察到的胰高血糖素反应迟钝与胰高血糖素分泌机制不成熟有关，而不是激素合成不足。这种不成熟可能与环磷酸腺苷（cAMP）合成受损和/或降解增强有关，或者与对cAMP的反应性降低有关。
