Long-term effects of prenatal undernutrition on female rat hypothalamic KNDy neurons

The nutritional environment during development periods induces metabolic programming, leading to metabolic disorders and detrimental influences on hum an reproductive health. This study aimed to determine the long-term adverse effect of in trauterine malnutrition on the reproductive center kisspeptin-neurokinin B-dynorphin A (KNDy) neurons in the hypothalamic arcuate nucleus (ARC) of female offspring. Twelve p regnant rats were divided into ad-lib-fed (control, n = 6) and 50% undernutrition (UN, n = 6) groups. The UN group was restricted to 50% daily food intake of the control dams from gestation day 9 until term delivery. Differences between the two groups in ter ms of various maternal parameters, including body weight (BW), pregnancy duration, and litter size, as well as birth weight, puberty onset, estrous cyclicity, pulsatile luteinizing hormone (LH) secretion, and hypothalamic gene expression of offspring, were determined. Female offspring of UN dams exhibited low BW from birth to 3 weeks, whereas UN offsp ring showed signs of precocious puberty; hypothalamic Tac3 (a neurokinin B gene) expression was increased in prepubertal UN offspring, and the BW at the virginal opening was lower in UN offspring than that in the control group. Interestingly, the UN offspring showed significant decreases in the number of KNDy gene-expressing cells after 29 weeks of age, but the number of ARC kisspeptin-immunoreactive cells, pulsatile LH secretions, and estrous cyclicity were comparable between the groups. In conclusion, intrauterine unde rnutrition induced various changes in KNDy gene expression depending on the life s tage. Thus, intrauterine undernutrition affected hypothalamic developmental programming in female rats

Microarray Analysis of Perinatal-Estrogen-Induced Changes in Gene Expression Related to Brain Sexual Differentiation in Mice

<div><p>Sexual dimorphism of the behaviors or physiological functions in mammals is mainly due to the sex difference of the brain. A number of studies have suggested that the brain is masculinized or defeminized by estradiol converted from testicular androgens in perinatal period in rodents. However, the mechanisms of estrogen action resulting in masculinization/defeminization of the brain have not been clarified yet. The large-scale analysis with microarray in the present study is an attempt to obtain the candidate gene(s) mediating the perinatal estrogen effect causing the brain sexual differentiation. Female mice were injected with estradiol benzoate (EB) or vehicle on the day of birth, and the hypothalamus was collected at either 1, 3, 6, 12, or 24 h after the EB injection. More than one hundred genes down-regulated by the EB treatment in a biphasic manner peaked at 3 h and 12-24 h after the EB treatment, while forty to seventy genes were constantly up-regulated after it. Twelve genes, including <i>Ptgds, Hcrt</i>, <i>Tmed2</i>, <i>Klc1</i>, and <i>Nedd4</i>, whose mRNA expressions were down-regulated by the neonatal EB treatment, were chosen for further examination by semiquantitative RT-PCR in the hypothalamus of perinatal intact male and female mice. We selected the genes based on the known profiles of their potential roles in brain development. mRNA expression levels of <i>Ptgds, Hcrt</i>, <i>Tmed2</i>, and <i>Nedd4</i> were significantly lower in male mice than females at the day of birth, suggesting that the genes are down-regulated by estrogen converted from testicular androgen in perinatal male mice. Some genes, such as <i>Ptgds</i> encoding prostaglandin D2 production enzyme and <i>Hcrt</i> encording orexin, have been reported to have a role in neuroprotection. Thus, <i>Ptgds</i> and <i>Hcrt</i> could be possible candidate genes, which may mediate the effect of perinatal estrogen responsible for brain sexual differentiation. </p> </div

Changes in expressions of <i>Tmed2</i>, <i>Klc1</i>, <i>Nedd4, Hcrt</i>, <i>Meis2</i>, <i>Neurod6</i>, <i>Pitx2, Ptgds</i>, <i>Vtn</i>, Fn <i>1</i>, <i>Apod</i>, and <i>Igf2</i> genes in the female mouse hypothalamus 3 h (A), 12 h (B), or 24 h (C) after the EB treatment.

<p>Values in EB-treated (solid circle) and vehicle-treated controls (open circle) are indicated as signal intensity in microarray hybridization. Values are means±SEM. Values marked with asterisks (* or **) are significantly different from vehicle-treated controls at each time point (P < 0.05 or P < 0.01, two-way ANOVA (treatment and time as main factors) followed by the Bonferroni test). </p