Biomedical subjects

Linda Brent

Publications and source records attributed to Linda Brent.

5 recordsLinked to original sources

PubMed2004

Excretion of urinary steroids in pre- and postpartum female baboons.

Steroid hormones are important regulators of a wide variety of reproductive and behavioral functions. We investigated the ability to track sex steroids and glucocorticoids in urine samples collected noninvasively from pre- and postpartum female baboons. Paired plasma and urine samples were collected every 2 weeks prior to and following birth in 10 females. Changes in concentrations of plasma steroids (estradiol, progesterone, and cortisol) were reflected in changes in urinary metabolite excretion (estrone conjugates, pregnanediol conjugates, and cortisol; r's>0.36, p's<0.001). A low correlation between prepartum plasma and urinary cortisol may reflect late-gestational changes in the production and/or metabolism of glucocorticoids. Steroid excretion profiles in a large sample of females giving birth and caring for healthy infants (n = 108) were compared with profiles obtained from females with poor maternal-fetal outcomes (late-term stillbirth, n = 14) and from females with significant postpartum problems with maternal care (n = 20). Mothers giving birth to stillborn infants had lower prepartum levels of urinary estrone conjugates and cortisol, suggesting reduced placental steroidogenesis. Mothers with postpartum behavioral difficulties had higher concentrations of prepartum estrone excretion, lower cortisol excretion, and elevated E/P ratios throughout the peripartum period. Noninvasive sample collection and enzyme immunoassay, therefore, have predictive utility regarding circulating steroid concentrations and can identify important endocrine correlates of physiological and behavioral abnormalities in baboons.

Animals↗

PubMed2004

The role of the endocrine system in baboon maternal behavior.

BACKGROUND: Human mothers display a wide range of parenting skills, and although we have gathered a large body of evidence on a variety of factors affecting maternal behavior, we still know relatively little about the physiologic correlates of variation in parental behavior in primates. METHODS: Excreted gonadal and adrenal steroids were measured across parturition in a large sample (n = 89) of group-living female baboons. Maternal behavior data were collected during the first 2 months of infants' life. RESULTS: We found that changes in the excreted sex steroid hormones and cortisol were associated with baboon mothers' infant-directed behaviors. Mothers who displayed more stress-related behaviors, who were also prone to maintain less contact with their infants, had higher postpartum cortisol levels, higher prepartum pregnanediol-3-glucoronide (PdG) levels, and lower postpartum PdG levels. Mothers with higher prepartum cortisol levels showed higher levels of infant-directed affiliative behaviors. CONCLUSIONS: These results point toward the importance of the whole endocrine system as a functional unit in terms of enhancing maternal care in primates. The dramatic physiologic changes occurring across parturition may act, in coordination with the cognitive-experiential system, to help the mother cope with the additional challenges imposed by the newborn.

Animals↗

PubMed2004

Hormonal correlates of changes in interest in unrelated infants across the peripartum period in female baboons (Papio hamadryas anubis sp.).

In past research on human and nonhuman primates, maternal responsiveness and behavior has been thought of as an experiential, cognitive mechanism; however, recent findings have shown that maternal motivation and behavior may not be entirely divorced from the endocrine system. To investigate the relationship between interest in infants and the hormonal changes related to pregnancy, we examined the nature of social interactions across parturition between a large sample (n = 133) of adult female baboons (Papio hamadryas anubis sp.) and unrelated infants. Prepartum data were collected during ten 30-min focal observations for each subject. Each mother-infant pair was then observed through the infant's first 8 weeks of life. A total of 2325 h of observation was recorded. Urine was collected on 65 subjects, starting 5 weeks before the expected date of parturition and ending 4 weeks after parturition. Evidence for a connection between endocrine function and responsiveness toward infants was found. Affiliative behaviors during the prepartum period were positively correlated to the estrogen/cortisol ratio and high dominance rank. In the postpartum period, affiliative behaviors were positively correlated with prepartum progesterone and dominance rank, and negatively correlated with postpartum cortisol levels. Finally, a positive correlation was recorded during the postpartum period between prepartum progesterone and aggression, and a negative correlation between postpartum cortisol and aggression and submission. Our data suggest that the endocrine changes that may help regulate maternal care of offspring also influence the way in which pre- and postpartum female baboons interact with unrelated infants in their social group.

Animals↗

PubMed2004

Solutions for research chimpanzees.

As one of humankind's closest animal relatives, the chimpanzee has proven to be a valuable but controversial research model. The author provides an overview of efforts to improve chimpanzee welfare, and describes a facility dedicated to providing lifelong care for these nonhuman primates following retirement from research.

Animal Experimentation↗

PubMed2002

Abnormal, abusive, and stress-related behaviors in baboon mothers.

BACKGROUND: Psychiatric disturbances during pregnancy and the postpartum period are especially serious, given the negative effects on the mother as well as the child. Understanding the causes of such disturbances has been difficult owing to the complexity of psychological, social, experiential, biological, and genetic factors involved. METHODS: To determine the potential utility of a nonhuman primate model for the study of postpartum disorders, the pathologic and stress-related behavior of 62 female baboons living in social groups was studied during pregnancy and after the birth of an infant. RESULTS: The prevalence of abnormal behavior and self-directed scratching (a measure of stress response) was higher after birth of the infant. Subjects displayed a significantly higher frequency per hour of these behaviors postpartum, which increased over 8 weeks. Abusive behaviors toward the infant were common, occurring in 55% of the subjects. Mothers with low dominance rank, who usually have lower levels of social support, had higher levels of abusive behavior during the postpartum period. CONCLUSIONS: Baboons show variation in measurable behaviors related to stress and abnormal functioning during the pre- and postpartum periods, indicating that a nonhuman primate model may be useful in the study of factors affecting postpartum psychiatric disorders and infant abuse.

Aggression↗