Early life pulsed antibiotic exposure impacts hypothalamic gene expression in males and females. Mean ± SE. Hypothalamic POMC expression in males (A,B) and females (C,D) after antibiotic pulses and at the and end of the study, respectively. Hypothalamic AGRP expression in males (E,F) and females (G,H) after antibiotic pulses and at the end of the study, respectively. Hypothalamic NPY expression in males (I,J) and females (K,L) after antibiotic pulses and at the end of the study, respectively. Hypothalamic IL-10 expression in males (M,N) and females (O,P) after antibiotic pulses and at the end of the study, respectively. Hypothalamic IRS-1 expression in males (Q,R) and females (S,T) after antibiotic pulses and at the end of the study, respectively. Hypothalamic IRS-2 expression in males (U,V) and females (W,X) after antibiotic pulses and at the end of the study, respectively. Results are shown as mean ± SEM (n = 7–10 rats/group). The superscripts a,b indicate significant differences between groups where labelled means without a common superscript letter differ, p < 0.05 (i.e., ‘a’ and ‘b’ differ; ‘ab’ does not differ from ‘a’ or ‘b’). CTR, control; ATB, antibiotic; PRE, prebiotic; ATB + PRE, antibiotic + prebiotic; LEAN, lean control. POMC, proopiomelanocortin; AGRP, agouti-related peptide; NPY, neuropeptide Y; IL-10, interleukin-10; IRS-1, insulin receptor substrate-1; IRS-2, insulin receptor substrate-2.