Cortisol concentrations in the milk of rhesus monkey mothers are associated with confident temperament in sons, but not daughters

## Abstract One pathway by which infant mammals gain information about their environment is through ingestion of milk. We assessed the relationship between stress‐induced cortisol concentrations in milk, maternal and offspring plasma, and offspring temperament in rhesus monkeys. Milk was collected from mothers after a brief separation from their infants at 3–4 months postpartum, and blood was drawn at this time for both mothers and infants. Offspring temperament was measured at the end of a 25‐hr assessment. Cortisol concentrations in milk were in a range comparable to those found in saliva, and were positively correlated with maternal plasma levels. Mothers of males had higher cortisol concentrations in milk than did mothers of females, and cortisol concentrations in maternal milk were related to a __Confident__ temperament factor in sons, but not daughters. This study provides the first evidence that naturally occurring variation in endogenous glucocorticoid concentrations in milk are associated with infant temperament. © 2010 Wiley Periodicals, Inc. Dev Psychobiol 53: 96–104, 2011. Cover ......Page 1 Contents ......Page 2 Big Science at the Table ......Page 3 Mother's Milk: A Rich Opportunity ......Page 6 The First Supper ......Page 9 Edible Advise ......Page 11 Of Beans and Genes ......Page 14 The Changing Notion of Food ......Page 17 More than Meets the Mouth ......Page 19 Tales of Adversity ......Page 21 A Flavour of the Future ......Page 22 Table 1 Hormonal and metabolic parameters and pancreas morphology......Page 24 References......Page 27 Methods References......Page 28 Figure 2 Female offspring demonstrate impaired glucose tolerance and insulin secretion to a glucose challenge.......Page 25 Table 2 Differentially expressed islet genes (P < 0.05) of female offspring in functionally enriched pathways......Page 26 Introduction......Page 29 Anthropometry and body composition......Page 30 Table 1 Anthropometric, biochemical and dietary parameters of the study participants stratified by the IGF rs680 genotype (data are presented as means±s.d.)......Page 31 Figure 1 Scatterplot of the observed values (open squares indicate GA+AA subjects; filled squares, GG subjects) and regression lines of predicted values (green line indicates GA+AA subjects; blue lines, GG subjects) of height values by IGF2 rs680 polymorp......Page 32 References......Page 33 Functional Genomics: Vitamin D and Disease ......Page 35 Introduction......Page 36 DNA isolation and clock genotyping......Page 37 Figure 1 Linkage disequilibrium (LD) plot across the CLOCK gene.......Page 38 Table 2 Characteristics of the population studied before and after behavioral treatment......Page 39 Table 4 Associations of CLOCK polymorphisms with changes in weight and metabolic parameters......Page 40 Figure 3 CLOCK variants and weight loss evolution during 28 weeks of treatment: (a) CLOCK rs3749474; (b) CLOCK rs4580704; (c) CLOCK rs180126 (3111TgtC).......Page 41 References......Page 42