RESUMO
Glycogen metabolism shapes ventromedial hypothalamic nucleus (VMN) control of glucose homeostasis. Brain glycogen mass undergoes compensatory expansion postrecovery from insulininduced hypoglycemia (IIH). Current research utilized combinatory highresolution microdissection/highsensitivity Western blotting to investigate whether IIH causes residual adjustments in glycogen metabolism within the metabolicsensory ventrolateral VMN (VMNvl). Micropunchdissected tissue was collected from rostral, middle, and caudal levels of the VMNvl in each sex for analysis of glycogen synthase (GS) and glycogen phosphorylase (GP)muscle type (GPmm; norepinephrinesensitive) and GPbrain type (GPbb; glucoprivicsensitive) isoform expression during and after IIH. Hypoglycemic suppression of VMNvl GS levels in males disappeared or continued after reestablishment of euglycemia, according to sampled segment. Yet, reductions in female VMNvl GS persisted after IIH. Males exhibited reductions in GPmm content in select rostrocaudal VMNvl segments, but this protein declined in each segment posthypoglycemia. Females, rather, showed augmented or diminished GPmm levels during IIH, but no residual effects of IIH on this protein. In each sex, regionspecific up or downregulation of VMNvl GPbb profiles during glucose decrements were undetected postrecovery from IIH. Results provide novel proof of estradioldependent sexdimorphic patterns of VMNvl GP variant expression at specific rostrocaudal levels of this critical glucoregulatory structure. Sex differences in persistence of IIHassociated GS and GPmm patterns of expression after restoration of euglycemia infer that VMNvl recovery from this metabolic stress may involve dissimilar glycogen accumulation in male versus female.