2008年1月19日 星期六

oxytocin and Autism

Oxytocin is a hormone released by the posterior pituitary gland. Its mechanical effects, particularly its stimulating effects on uterine contractions during labour, have been known for a long time. Recently we learned that oxytocin also has important behavioral effects. Today we are in a position to summarize the results of dozens of studies by claiming that oxytocin is the typical hormone of love: Whichever facet of love one considers, oxytocin is involved.


— Jan TrittenEditor in Chief, Midwifery Today

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We have many reasons to suspect a link between "autism epidemic" and "labour induction epidemic."

  1. The first reason is that in all studies that took into account independently the variable "labour induction," it appeared as a risk factor. Labour induction should be explicitly taken into consideration by epidemiologists, because it can be associated either with birth by the vaginal route (with or without intervention such as forceps), or with cesarean birth.
  2. Another reason is that the epidemic of autism and the epidemic of induction seem to have developed side by side in Western countries and in China. Bai, from the Association of Rehabilitation for Children with Autism of Wuhan City, estimates that the number of children with autism is growing at an annual rate of 20 percent in that country, higher than the world average of 14 percent (http://news.xinhuanet.com/english/2004-08/11/content_1759576.htm). Let us recall that the rate of inductions is growing fast in China, since the Chinese are autonomous for synthesizing misoprostol.
  3. A third reason is that the results of recent studies suggest that children with autistic disorder show alterations in their oxytocin system. The first clues came from a study of mid-day blood samples from 29 autistic and 30 age-matched normal children, all prepubertal.(Modahl, C., et al. Plasma oxytocin levels in autistic children. 1998. Biol Psychiatry (4): 270–77) The autistic group appeared to have significantly lower blood oxytocin levels than the normal group. Oxytocin increased with age in the normal but not in the autistic children. These results inspired an in-depth inquiry into the oxytocin system of autistic children.

.......

We are learning that, among humans, the period surrounding birth is a period of dramatic reorganization of central oxytocin binding. Artificial induction of labour creates situations that undoubtedly interfere with the development and the reorganization of the oxytocin system in such a critical period. This fact alone is a reason for further epidemiological studies (about the current autism epidemic) focusing on labour induction as a possible risk factor. It would be useful to know also how autistic children release oxytocin. Oxytocin is more effective when released rhythmically, in a succession of fast pulsations. Today it is possible to measure the rhythmicity "the pulsatility" of oxytocin release. In other words, the time has come to study autism as an "impaired capacity to love."

related researches posted at:

http://docs.google.com/Doc?id=dcvv3sw9_54gr97r2c8

http://docs.google.com/Doc?id=dcvv3sw9_55cwpj7xfz

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