Sucrose consumption alters steroid and dopamine signalling in the female rat brain

Abstract

Sucrose consumption is associated with type 2 diabetes, cardiovascular disease, and cognitive deficits. Sucrose intake during pregnancy might have particularly prominent effects on metabolic, endocrine, and neural physiology. It remains unclear how consumption of sucrose affects parous females, especially in brain circuits that mediate food consumption and reward processing. Here, we examine whether a human-relevant level of sucrose before, during, and after pregnancy (17–18 weeks total) influences metabolic and neuroendocrine physiology in female rats. Females were fed either a control diet or a macronutrient-matched, isocaloric sucrose diet (25% of kcal from sucrose). Metabolically, sucrose impairs glucose tolerance, increases liver lipids, and increases a marker of adipose inflammation, but has no effect on body weight or overall visceral adiposity. Sucrose also decreases corticosterone levels in serum but not in the brain. Sucrose increases progesterone levels in serum and in the brain and increases the brain:serum ratio of progesterone in the mesocorticolimbic system and hypothalamus. These data suggest a dysregulation of systemic and local steroid signalling. Moreover, sucrose decreases tyrosine hydroxylase (TH), a catecholamine-synthetic enzyme, in the medial prefrontal cortex. Finally, sucrose consumption alters the expression pattern of FOSB, a marker of phasic dopamine signalling, in the nucleus accumbens. Overall, chronic consumption of sucrose at a human-relevant level alters metabolism, steroid levels, and brain dopamine signalling in a female rat model.

Profiling of systemic and brain steroids in male songbirds: Seasonal changes in neurosteroids

“…When detectable samples in a group were ≥ 20%, missing values were estimated via quantile regression imputation of left-censored missing data using the metimp web tool. [37][38][39] When detectable samples in a group were < 20%, non-detectable Note: Sample amount used was 5 µL of blood, 10 µL of plasma, and 0.98 mg of brain.…”

“…Steroids were extracted from blood, plasma and brain tissue using liquid‐liquid extraction, as described previously 36,37 . Briefly, five zirconium ceramic oxide beads (diameter 1.4 mm; Thermo Fisher Scientific) were added to each vial.…”

“…A value was considered non‐detectable if it was below the lowest standard on the calibration curve. When detectable samples in a group were ≥ 20%, missing values were estimated via quantile regression imputation of left‐censored missing data using the metimp web tool 37‐39 . When detectable samples in a group were < 20%, non‐detectable values were set to 0.…”

“…When detectable samples in a group were < 20%, non‐detectable values were set to 0. To make a comparison between steroid levels in brain and blood, we assumed that 1 mL of blood weighs 1 g 33,37 …”

“…Steroids were extracted from blood, plasma and brain tissue using liquid-liquid extraction, as described previously. 36,37…”