Thu, 21 Aug 2008 07:15:46 BST CiteULike: omalbams Raskind http://www.citeulike.org/user/omalbam/author/Raskind CiteULike.org en-gb Copyright © 2004-2008 citeulike.org http://www.citeulike.org/user/omalbam/article/2315968 <i>Psychoneuroendocrinology, Vol. 29, No. 1. (January 2004), pp. 65-82.</i><br /><br />BACKGROUND: Our laboratory has previously reported that testosterone (T) administration to older men significantly improves cognitive function. This study examined potential changes in insulin-like growth factor (IGF) IGF-I, IGF-II and IGF-related binding proteins in response to T administration in older men and their relationship to cognitive functioning. METHODS: Twenty-five healthy community dwelling volunteers, ranging in age from 50-80 years were randomized to receive weekly intra-muscular (i.m.) injections of either 100 mg T enanthate or placebo (saline) for 6 weeks. Serum hormone levels and cognitive functioning was assessed at baseline and twice during treatment. RESULTS: Significant positive associations between IGF-I and IGF-II and spatial memory, spatial reasoning, and verbal fluency were observed after 6 weeks of T administration. Increased serum T levels from treatment were positively associated with improvement in spatial reasoning performance, whereas estradiol was associated with a decline in divided attention performance. Serum IGF-I, IGF-II and IGFBPs did not change in response to T treatment. CONCLUSIONS: Our results suggest that T, estradiol and IGF-I may have independent and selective effects on cognitive functioning. Positive associations between T levels and cognition are consistent with an effect of androgen treatment, whereas positive associations between IGF-I levels and cognition are reflective of a relationship between endogenous IGF-I levels and cognition. Relationship between testosterone supplementation and insulin-like growth factor-I levels and cognition in healthy older men. MM Cherrier S Plymate S Mohan S Asthana AM Matsumoto W Bremner E Peskind M Raskind S Latendresse AP Haley S Craft Psychoneuroendocrinology, Vol. 29, No. 1. (January 2004), pp. 65-82. 2008-01-31T19:28:11-00:00 2004 Psychoneuroendocrinology 0306-4530 29 1 65 82 aging igf testosterone therapy