Deletion of PTP 1B from Brain Neurons Partly Protects Mice from Diet-Induced Obesity and Minimally Improves Fertility.

Reproductive dysfunction in women has been linked to high calorie diet (HCD)-feeding and obesity. Central resistance to leptin and insulin have been shown to accompany diet-induced infertility in rodent studies, and we have previously shown that deleting suppressor of cytokine signaling 3, which is a negative regulator of leptin signaling, from all forebrain neurons partially protects mice from HCD-induced infertility. In this study, we were interested in exploring the role of protein tyrosine phosphatase 1B (PTP1B), which is a negative regulator of both leptin and insulin signaling, in the pathophysiology of HCD-induced obesity and infertility. To this end, we generated male and female neuron-specific PTP1B knockout mice and compared their body weight gain, food intake, glucose tolerance and fertility to control littermates under both normal calorie diet-feeding and HCD-feeding conditions. Both male and female mice with neuronal PTP1B deletion exhibited slower body weight gain in response to HCD-feeding, yet only male knockout mice exhibited improved glucose tolerance compared with controls. Neuronal PTP1B deletion improved the time to first litter in HCD-fed mice, but did not protect female mice from eventual HCD-induced infertility. While the mice fed a normal caloric diet remained fertile throughout the 150 day period of assessment, HCD-fed females became infertile after producing only a single litter, regardless of their genotype. These data show that neuronal PTP1B deletion is able to partially protect mice from HCD-induced obesity, but is not a critical mediator of HCD-induced infertility.