Prenatal dexamethasone exposure induces changes in nonhuman primate offspring cardiometabolic and hypothalamic-pituitary-adrenal axis function.

Prenatal stress or glucocorticoid administration has persisting "programming" effects on offspring in rodents and other model species. Multiple doses of glucocorticoids are in widespread use in obstetric practice. To examine the clinical relevance of glucocorticoid programming, we gave 50, 120, or 200 microg/kg/d of dexamethasone (dex50, dex120, or dex200) orally from mid-term to a singleton-bearing nonhuman primate, Chlorocebus aethiops (African vervet). Dexamethasone dose-dependently reduced maternal cortisol levels without effecting maternal blood pressure, glucose, electrolytes, or weight gain. Birth weight was unaffected by any dexamethasone dose, although postnatal growth was attenuated after dex120 and dex200. At 8 months of age, dex120 and dex200 offspring showed impaired glucose tolerance and hyperinsulinemia, with reduced (approximately 25%) pancreatic beta cell number at 12 months. Dex120 and dex200 offspring had increased systolic and diastolic blood pressures at 12 months. Mild stress produced an exaggerated cortisol response in dex200 offspring, implying hypothalamic-pituitary-adrenal axis programming. The data are compatible with the extrapolation of the glucocorticoid programming hypothesis to primates and indicate that repeated glucocorticoid therapy and perhaps chronic stress in humans may have long-term effects.

Hyperglycaemia and reduced glucokinase expression in weanling offspring from dams maintained on a high-fat diet.

High-fat feeding reduces the expression of GLUT-2 and the glycolytic enzyme glucokinase (GK). The transcription factor, pancreatic duodenal homeobox-1 (Pdx-1), is important for beta-cell maintenance. The aim of the present study was to determine, in weanling Wistar rats, the effect of a maternal high-fat diet (HFD) during defined periods of gestation and lactation, on body weight, circulating glucose and insulin concentrations, and the expression of GLUT-2, GK and Pdx-1. At postnatal day 21, weights were recorded and glucose and insulin concentrations were measured. The expression levels for mRNA were quantified by LightCycler PCR. Pancreatic sections, immunostained for GLUT-2, GK or Pdx-1, were assessed by image analysis. Weanlings from dams fed an HFD throughout gestation were lighter, with heavier weanlings produced from dams fed an HFD throughout gestation and lactation. Both these groups of weanlings were normoglycaemic, all the others being hyperglycaemic. Hypoinsulinaemia was evident in weanlings from dams fed an HFD throughout gestation only and also for either the first week of lactation or throughout lactation. GLUT-2 mRNA expression was reduced and GLUT-2 immunoreactivity was increased in most of the weanlings. GK mRNA expression and immunoreactivity was reduced in most of the offspring. Pdx-1 mRNA expression was increased in weanlings from dams fed an HFD throughout both gestation and lactation and reduced in those from dams only fed a lactational HFD. Normal Pdx-1 immunoreactivity was found in all of the weanlings. A maternal HFD induces hyperglycaemia in weanlings concomitant with reduced GK expression which may compromise beta-cell function.

Fluoxetine decreases stereotypic behavior in primates.

BACKGROUND: Primates reared in captivity may display stereotypic behaviors. These behaviors are arguably reminiscent of human obsessive-compulsive or posttraumatic symptoms, which respond to selective serotonin reuptake inhibitors (SSRIs). Captive primates with marked stereotypic behaviors were entered into a randomized controlled study of the SSRI, fluoxetine. METHODS: A sample of 10 vervet monkeys with behaviors such as marked saluting, somersaulting, weaving, or head tossing was selected. Subjects were randomized to receive fluoxetine 1 mg/kg for 6 weeks (n=5) or no treatment (n=5). A rater blind to the medication status of subjects noted the frequency of the stereotypic behaviors. RESULTS: Repeated-measures analysis of variance (RM-ANOVA) demonstrated a significant GroupxTime difference with significantly fewer stereotypic symptoms in the fluoxetine group by endpoint. At this time, three of the five fluoxetine-treated subjects (but none of the no-treatment subjects) were responders on the Clinical Global Impressions (CGI) change item (CGI < or =2). CONCLUSIONS: Stereotypic behaviors in captive vervets gradually and partially decrease in response to administration of an SSRI, paralleling research on human anxiety symptoms. Further research on animal stereotypies may be useful in providing appropriate veterinary care, and in exploring the underlying neurobiology of certain psychiatric disorders.