We asked Dr. Sapolsky if neonatal handling was particularly stressful for subjects.  He said that prior to the 1980s, neonatal handling was viewed as a neuroendocrine stressor that helped stress-immunization later in life.  However as research progressed, it was found that while fetal rats have adult levels of glucocorticoid secretion, postnatal rats lack glucocorticoid secretion altogether.  Therefore the effect of neonatal handling cannot be attributed to a change in glucocorticoid secretion postnatally.  It was then that Sapolsky and Meaney turned to alternative mechanisms for the handling effect, such as thyroid hormone secretion and maternal nurtuing.

Click here to watch Dr. Sapolsky address neonatal glucocorticoid secretion and whether or not neonatal handling is stressful. (8:14-10:48)