Meeting Abstract

P3.104  Saturday, Jan. 5  Capture-handling stress and its effects upon hypothalamic EGR-1 and GnIH expression in House sparrows (Passer domesticus) CALISI, R.M.*; RIZZO, N.O.; BENTLEY, G.E.; Univ. of California, Berkeley; Univ. of California, Berkeley; Univ. of California, Berkeley calisi@berkeley.edu

Gonadotropin-releasing hormone (GnRH) is a critical component of the vertebrate reproductive axis and directly influences pituitary gonadotropin release. A recently discovered neuropeptide, gonadotropin-inhibitory hormone (GnIH), directly inhibits pituitary gonadotropin synthesis and release. Stress is a known inhibitor of reproductive function. We hypothesized that stress effects upon reproduction might be mediated via the hypothalamic GnIH system. We examined the effects of capture-handling stress on the numbers of GnIH neurons as well as the expression of the protein product of the immediate-early gene EGR-1, in the hypothalamus of male and female adult house sparrows (Passer domesticus) during early and late breeding seasons. Preliminary data indicate increases in the numbers of GnIH and EGR-1 �positive neurons after capture-handling stress. These correlative data, along with our previous data from rodents, imply an influence of stress upon the hypothalamus and the GnIH system. Thus GnIH might be a mediator of stress-induced reproductive disruption in birds and mammals.