PPARGC1A and obesity due to melanocortin 4 receptor deficiency: Nicotine, during pregnancy and lactation, reduces BAT vascularization during early development and BAT phenotype characteristics in adulthood by downregulating the activity of the PGC-1α-UCP1 signaling pathway, which may be a reason for nicotine-induced obesity in female offspring, which is consistent with the results of our study [26].