Dinh TT, I’Anson H, Ritter S (2003) Poster: Immunotoxic destruction of distinct catecholaminergic neuron populations disrupts the reproductive response to glucoprivation in female rats. Neuroscience 2003 Abstracts 827.13. Society for Neuroscience, New Orleans, LA.
Summary: Chronic glucoprivation suppresses estrous cyclicity in hamsters (Schneider et al. 1997) and rats (I’Anson et al. 2003). This suppression can be viewed as an adaptive glucoregulatory response since by delaying pregnancy, it conserves metabolic fuels for maternal survival. Our previous work shows that corticosterone, feeding and adrenal medullary responses to glucoprivation are controlled by hindbrain glucose sensing cells and require activation of ascending or descending catecholamine neurons. The glucoreceptors responsible for the delay of estrous also appear to be located in hindbrain, since fourth ventricular infusion of low 2-deoxy-D-glucose (2DG) doses suppresses pulsatile LH secretion in rats (Nagatani et al. 1996). Here we tested the involvement of catecholamine neurons in suppressing estrous cycles during chronic glucoprivation. We microinjected the retrogradely transported immunotoxin, anti-dopamine beta hydroxylase (dbh)-conjugated to saporin (DSAP), bilaterally into the paraventricular nucleus of the hypothalamus (PVH) of female rats to selectively destroy dbh-containing catecholamine neurons projecting to this area. Neither DSAP nor unconjugated saporin (SAP) control injections altered basal estrous cycle length. To assess effects of chronic 2DG, rats were injected with 2DG (200 mg/kg every 6 hr for 72 hr) beginning 24 hr after detection of estrous following two normal 4-5 day cycles. Chronic glucoprivation increased cycle length significantly in 7/8 SAP controls but in only 1/8 DSAP rats. Lesion effectiveness and selectivity were confirmed by immunohistochemistry. Thus, hindbrain catecholamine neurons with projections to the PVH are not required for estrous cyclicity when metabolic fuels are abundant, but are required for inhibition of reproductive function during chronic glucose deficit.
Related Products: Anti-DBH-SAP (Cat. #IT-03)