Hypothalamic Noradrenergic Hyperactivity and Detrimental Bone Status in an Animal Model of Nutritional Growth Retardation

摘要

We have studied hypothalamic noradrenergic activity in relation with bone status in a nutritional growth retardationmodel (ND). Control rats (C) were fed ad libitum. ND received 80% of the diet consumed by C for 4 weeks andlater refed ad libitum for 8 weeks. Food restriction induced detrimental effects on body and femur weight and length(P<0.05) and bone biomechanical properties (P<0.001). Thickness of proliferative and hypertrophic zone (μm) of growthplate cartilage and bone volume (%, mean±SE) were 225.96±5.70 v. 280.70±12.52, 95.16±5.81 v. 134.60±9.30,17.64±3.23 v. 26.80±2.03, respectively (P<0.05); anterior and posterior hypothalamus norepinephrine uptake and releaseand tyrosine hydroxylase activity (% of control) were 79.05±3.56, 67.00±10.00, 164.26±16.58 and 80.65±5.92,147.00±1.00, 152.42±9.30, respectively (P<0.05). Thus, impaired biomechanical bone performance in ND could be due,in part, to the increased hypothalamic noradrenergic activity in response to restriction. Normalization of parameters withrefeeding suggests no long-term side-effects in undernourished rats.