Nicotine exposure during breastfeeding reduces sympathetic activity in brown adipose tissue and increases in white adipose tissue in adult rats: Sex-related differences.

Nicotine transfer via breast milk induces obesity in the adult offspring. We hypothesize that sympathetic nervous system (SNS) activity, brown adipose tissue (BAT) thermogenesis and white adipose tissue (WAT) lipogenesis/adipogenesis are altered in adult rats that were exposed to nicotine exclusively during the breastfeeding period. Lactating Wistar rats were separated into two groups: nicotine (NIC), dams implanted with osmotic minipumps containing 6 mg/kg of nicotine at postnatal day (PN) 2; control, dams were implanted with saline-containing minipumps. Euthanasia occurred at PN120 or PN180. NIC offspring had lower BAT SNS activity and higher BAT lipid content. NIC males showed lower UCP1, ß3-AR and CPT1a, while NIC females showed lower UCP1, TRα1, CPT1a, suggesting lower thermogenesis. NIC males showed higher WAT SNS activity, WAT ß3-AR, adrenal catecholamine, FAS, PPARγ and adipocytes area, while NIC females showed higher ACC, FAS, CEBPß and PPARγ. These findings indicate increased lipogenesis/adipogenesis in both sexes, with a possible compensatory sympathetic activated-lipolysis in males. NIC males had higher hypothalamic pAMPK/AMPK, explaining the lower BAT sympathetic activity. Neonatal nicotine exposure reduces BAT SNS activity and thermogenesis, and, only in males, increases WAT adipogenesis/lipogenesis, despite higher WAT SNS activity. These alterations can be associated with obesogenesis in this programming model.

Early weaning alters the thermogenic capacity of brown adipose tissue in adult male and female rats.

PURPOSE: Early weaning (EW) is a risk factor for obesity development. Brown adipose tissue (BAT) hypofunction is related to obesity onset. Here, we evaluated whether sympathetic nervous system (SNS) activity in BAT and the thermogenic function of BAT are decreased in adulthood in obese rats from two EW models. METHODS: At the time of birth, lactating Wistar rats and their pups (three males and three females) were separated into three groups: the control group, in which pups consumed milk throughout lactation; the non-pharmacological EW (NPEW) group, in which suckling was interrupted with a bandage during the last 3 days of lactation; and the pharmacological EW (PEW) group, in which dams were treated with bromocriptine (0.5 mg/twice a day) 3 days before weaning. The offspring were sacrificed on PN180. RESULTS: Adult male rats from both EW models exhibited lower BAT SNS activity. Female rats from the PEW group showed a decrease in BAT SNS activity. The protein levels of UCP1 were lower in the NPEW males, while PGC1α levels were lower in both PEW and NPEW males. Both groups of EW females showed reductions in the levels of ß3-AR, TRß1, and PGC1α. The UCP1 protein level was reduced only in the NPEW females. The EW groups of both sexes had lower AMPK protein levels in BAT. In the hypothalamus, only the PEW females showed an increase in AMPK protein levels. In both groups of EW males, adrenal catecholamine was increased and tyrosine hydroxylase was decreased, while in EW females, adrenal catecholamine was decreased. CONCLUSIONS: Early weaning alters the thermogenic capacity of BAT, which partially contributes to obesity in adulthood, and there are sex-related differences in these alterations.

Cigarette smoke during lactation in rat female progeny: Late effects on endocannabinoid and dopaminergic systems.

AIMS: Maternal smoking is considered a risk factor for childhood obesity. In a rat model of tobacco exposure during breastfeeding, we previously reported hyperphagia, overweight, increased visceral fat and hyperleptinemia in adult female offspring. Obesity and eating disorders are associated with impairment in the endocannabinoid (EC) and dopaminergic (DA) systems. Considering that women are prone to eating disorders, we hypothesize that adult female Wistar rats that were exposed to cigarette smoke (CS) during the suckling period would develop EC and DA systems deregulation, possibly explaining the eating disorder in this model. MATERIAL AND METHODS: To mimic maternal smoking, from postnatal day 3 to 21, dams and offspring were exposed to a smoking machine, 4×/day/1 h (CS group). Control animals were exposed to ambient air. Offspring were evaluated at 26 weeks of age. KEY FINDINGS: Concerning the EC system, the CS group had increased expression of diacylglycerol lipase (DAGL) in the lateral hypothalamus (LH) and decreased in the liver. In the visceral adipose tissue, the EC receptor (CB1r) was decreased. Regarding the DA system, the CS group showed higher dopamine transporter (DAT) protein expression in the prefrontal cortex (PFC) and lower DA receptor (D2r) in the arcuate nucleus (ARC). We also assessed the hypothalamic leptin signaling, which was shown to be unchanged. CS offspring showed decreased plasma 17ß-estradiol. SIGNIFICANCE: Neonatal CS exposure induces changes in some biomarkers of the EC and DA systems, which can partially explain the hyperphagia observed in female rats.