Prenatal Stress
Adolescents stop growing when the ends of the long bones meet and begin to fuse, but for complex reasons, Testosterone, by accelerating the growth of the ends of long bones, can actually speed the cessation of growth. Thus, pubescent boys given testosterone will, paradoxically, wind up having their adult stature blunted a bit. (Location 1585)
⇒ Adolescence
If you were a first-trimester fetus during the famine, that programs you for a greater risk of heart disease, obesity, and an unhealthy cholesterol profile, whereas if you were a second- or third-trimester fetus, that programs you for a greater Diabetes risk. (Location 1623)
⇒ SES socioeconomic status
low birth weight still predicts an increased risk of diabetes and hypertension. These are big effects. When you compare those who were heaviest versus lightest at birth, you see an approximate eight-fold difference in the risk of pre-diabetes, and about an eighteen-fold difference in the risk of Metabolic syndrome. Among both men and women, compare those whose birth weights were in the lowest 25 percent versus those in the highest 25 percent, and the former have a 50 percent higher rate of death from heart disease. (Location 1629)
do non-nutritional stressors during pregnancy also induce FOAD-like effects? The answer is, yes. (Location 1637)
Fetuses can monitor signals of Stress from the mother, insofar as Glucocorticoids readily pass through to the fetal circulation, and lots of glucocorticoids “teach” the fetus that it is indeed a stressful world out there. The result? Be prepared for that stressful world: tend toward secreting excessive amounts of glucocorticoids. (Location 1641)
prenatal stress programs humans for higher glucocorticoid secretion in adulthood as well. In these studies, low birth weight (corrected for body length) is used as a surrogate marker for stressors during fetal life, (Location 1650)
if you stress pregnant rats, you “demasculinize” the male fetuses. They are less sexually active as adults, and have less developed genitals. As we will see in the next chapter, ==stress decreases Testosterone secretion==, and it seems to do so in male fetuses as well. Furthermore, glucocorticoids and testosterone have similar chemical structures (they are both “steroid” hormones), and a lot of glucocorticoids in a fetus can begin to gum up and block receptors for testosterone, making it impossible for the testosterone to have its effects. (Location 1662)
Prenatally stressed rats, as adults, freeze up when around bright lights, can’t learn in novel settings, defecate like crazy. Sad. As we will see in chapter 15, anxiety revolves around a part of the brain called the Amygdala, and prenatal stress programs the amygdala into a lifelong profile that has anxiety written all over it. ==The amygdala winds up with more receptors for glucocorticoids==, more of a neurotransmitter that mediates anxiety, and fewer receptors for a brain chemical that reduces anxiety.* Does prenatal stress in humans make for anxious adults? It’s difficult to study this in humans, in that it is hard to find mothers who are anxious during pregnancy, or anxious while their child is growing up, but not both. So there’s not a huge amount of evidence for this happening in humans. (Location 1670)
Prenatally stressed rodents grow up to have fewer connections between the neurons in a key area of the brain involved in learning and memory, and have more impairments of memory in old age, while prenatally stressed nonhuman primates have memory problems and form fewer neurons as well. (Location 1678)
⇒ memory processing, Memory retrieval under the control of the prefrontal cortex
amid consuming an average amount of food, her fetus gets a less than average share of it, producing mild malnutrition. And thus programs a milder version of a thrifty metabolism. And when that fetus eventually becomes pregnant…. In other words, these FOADish tendencies can be transmitted across generations, without the benefit of genes. It’s not due to shared genes, but to shared environment, namely, the intimately shared blood supply during gestation. (Location 1687)
So you have Mom, who is Insulin-resistant because she has too much energy stored away, releasing hormones that make the normal-weight fetus bad at energy storage as well…and the fetus winds up underweight and with a thrifty metabolic view of the world. (Location 1698)
⇒ 080 🥗Ernährung
see also
Tags: neurobiology science
Superlink: 051 ☣Neurobiology 050 🧠Neuroscience
Source
6 Dwarfism and the Importance of Mothers
Created: 03-09-22 16:09