Kuhn C M, McMillian M K, Schanberg S M
J Pharmacol Exp Ther. 1983 Apr;225(1):50-6.
We have previously reported that maternal deprivation of rat pups causes a decrease in tissue responsiveness to growth hormone that is mediated by the loss of maternal tactile stimulation. We now report that liver responses to alpha and beta adrenergic agonists as well as glucagon and vasopressin decrease during maternal deprivation. However, the decreased responsiveness to these agents is mediated by short-term food deprivation (FD) rather than loss of maternal tactile stimulation. When 8-day-old rat pups were separated from the mother or placed with a nipple-ligated mother for 2 hr and then injected with phenylephrine, isoproterenol or glucagon, liver ornithine decarboxylase (ODC) activity did not increase, although ODC activity increased markedly in control pups after administration of these agents. This loss of responsiveness appears to be both tissue- and drug-specific, as liver ODC responses to dexamethasone, dibutyryl cyclic AMP and prostaglandin E-1 and heart ODC responses to phenylephrine were not affected. FD had only a slight effect on glycogen phosphorylase activation by phenylephrine and had no effect on phenylephrine-induced glycogen depletion. Finally, FD did not affect the number of alpha-1 or beta receptors in liver of rat pups. These findings suggest that short-term FD selectively decreases liver ODC responses to certain agonists including alpha and beta adrenergic agonists by postreceptor mechanisms.
我们之前曾报道，剥夺幼鼠的母源会导致组织对生长激素的反应性降低，这是由母源触觉刺激的丧失介导的。我们现在报道，在母源剥夺期间，肝脏对α和β肾上腺素能激动剂以及胰高血糖素和血管加压素的反应会降低。然而，对这些药物反应性的降低是由短期食物剥夺（FD）介导的，而不是母源触觉刺激的丧失。当8日龄的幼鼠与母亲分离或与乳头结扎的母亲一起放置2小时，然后注射去氧肾上腺素、异丙肾上腺素或胰高血糖素时，肝脏鸟氨酸脱羧酶（ODC）活性并未增加，尽管在给予这些药物后，对照幼鼠的ODC活性显著增加。这种反应性的丧失似乎具有组织和药物特异性，因为肝脏ODC对地塞米松、二丁酰环磷酸腺苷和前列腺素E-1的反应以及心脏ODC对去氧肾上腺素的反应均未受到影响。FD对去氧肾上腺素激活糖原磷酸化酶的作用很小，对去氧肾上腺素诱导的糖原消耗没有影响。最后，FD不影响幼鼠肝脏中α-1或β受体的数量。这些发现表明，短期FD通过受体后机制选择性地降低肝脏ODC对某些激动剂（包括α和β肾上腺素能激动剂）的反应。
