Accelerated aging of reproductive capacity in male rat offspring of protein-restricted mothers is associated with increased testicular and sperm oxidative stress.

Maternal protein restriction (MPR) in pregnancy causes life course organ dysfunction, but few studies link the developmental origins of disease hypothesis to early aging. Suboptimal developmental nutrition increases oxidative stress (OS) and male infertility, damaging sperm function. We hypothesized that MPR in pregnancy accelerates age-related changes in testicular and sperm function related to both maternal diet and increased testicular OS in rat offspring. We studied male rats whose pregnant mothers ate either control (C, 20 % casein) or restricted (R, 10 % casein) isocaloric diet. After birth, mothers and offspring ate C diet. Testes were retrieved at 19 days gestation and across the life course (postnatal day (PND) 21, 36, 110, and 850) to measure OS markers, antioxidant enzymes, serum FSH, LH, and testosterone, and PND 110 sperm OS and quality. Fertility rate was evaluated at PND 110, 450, and 850. Offspring showed age- and MPR-related changes in testosterone, testicular OS markers and antioxidant enzymes and fertility, and maternal diet-related OS and sperm antioxidant enzyme changes. Developmental programming is considered a key factor in predisposing to chronic disease. Our data show that programming also plays an important role in aging trajectory. This interaction is a little studied area in aging biology that merits more investigation.

Preliminary evidence of accumulation of stress during translocation in mantled howlers.

Translocation--an extensively used conservation tool--is a potentially stressful event, as animals are exposed to multiple stressors and cannot predict or control the changes in their environment. Therefore, it may be expected that during a translocation program stress accumulates and social behavior changes. Here, we present data from a translocation of four adult mantled howlers (Alouatta palliata), which was conducted in southern Veracruz (Mexico). We found that stress (measured in fecal corticosterone) increased during translocation, but that the rate of both affiliative and agonistic interactions remained unchanged. Females showed higher levels of corticosterone than males throughout translocation, although no sex differences were observed in social interactions. Our findings provide a preliminary evidence for accumulation of physiological stress during translocation in primates, and may have implications for decisions concerning releasing practices.

Effects of a maternal low protein isocaloric diet on milk leptin and progeny serum leptin concentration and appetitive behavior in the first 21 days of neonatal life in the rat.

Suboptimal developmental environments program offspring to lifelong metabolic problems. We evaluated effects of maternal isocaloric low protein diet during pregnancy and/or lactation on milk quantity and leptin concentration at postnatal day 7, 14, and 21. Control mothers ate 20% casein (C) and restricted mothers (R) 10% casein to provide four groups: CC, RR, CR, and RC (first letter pregnancy and second lactation diet) to enable evaluation of effects influenced by maternal diet during pregnancy and lactation. Milk leptin was not a determinant of pup serum leptin. Pup serum leptin did not inhibit milk appetite at any postnatal age. Pup serum leptin did not correlate with pup adipose tissue. Finally, the normal postnatal leptin rise in pup serum was delayed by prenatal undernutrition. These data suggest that fetal nutrition modifies timing of neonatal leptin surge and may contribute to the development of altered appetite and metabolic disorders in later life.

Glucocorticoid levels in free ranging resident mantled howlers: a study of coping strategies.

A growing amount of data shows that a preference for passive-nonaggressive over active-aggressive problem solving is associated with higher levels of glucocorticoids (GC). For mantled howlers, the arrival of an adult male in a new group is a potential source of psychological stress for both resident males and females. Resident mantled howler males take an active stand and aggressively repel the entrance of solitary males, while females take a passive-nonaggressive stand. In order to study whether the relationship between coping strategies and the activation of the hypothalamic-pituitary-adrenal (HPA) axis observed in other species applies to the response of resident mantled howlers to the presence of solitary males, we examine the relationship between different group and subpopulation variables and the GC levels measured in feces collected from 10 groups living in six forest fragments, in Los Tuxtlas, Mexico. The results of our study suggest that the resident mantled howler females' passive response to the presence of solitary males is accompanied by the activation of the HPA axis, whereas resident males' aggressive response is not accompanied by any changes in the HPA axis. In contrast, a previous study suggests that resident male howlers respond by increasing their testosterone levels to the presence of solitary males (Cristobal-Azkarate et al., Hormones and Behavior 2006;49 261-267). These different behavioral and hormonal responses coincide with the active and passive coping styles described for other species. The conditions in which howlers live in our study area may be favoring the interaction between solitary and resident howlers, and inducing chronically high GC levels, which in turn could negatively affect the fitness of these subpopulations.

Testosterone levels of free-ranging resident mantled howler monkey males in relation to the number and density of solitary males: a test of the challenge hypothesis.

The challenge hypothesis asserts that testosterone levels and aggression in male adult animals are closely associated with one another in the context of intense reproductive competition, particularly when males challenge one another for the access to females. For mantled howler monkeys (Alouatta palliata), the presence of a solitary male in the vicinity of a social group can be considered a threat for the reproductive success of the resident males, as group takeovers by solitary males are followed by a reestablishment of the access to females among group males and sometimes by infanticide. Therefore, these episodes should be accompanied by an increase in testosterone secretion according to the challenge hypothesis. In order to test our prediction, we relate different group and subpopulation variables to the testosterone levels measured in feces collected from 10 groups living in 6 forest fragments, at Los Tuxtlas, Mexico. Our results suggest that resident A. palliata males regard solitary individuals as potential contesters for their reproductive success and that they respond to interactions with them with an increase in testosterone levels, that is increasing their aggressiveness. Our results also suggest that in the studied groups all males have at least certain access to mates and that the entrance of a new male would affect their reproductive success negatively. Finally, the negative effects of chronically high testosterone levels may be negatively affecting the fitness of our study groups living in high population densities and small fragments.

Variación en la ingestión de energía y sus fuentes durante el ciclo mestrual / Variation in energy intake and sources during menstrual cycle

Diez mujeres mexicanas sanas (18-25 años), estudiantes de nutriología, registraron su ingestión de alimentos durante 2 ciclos mestruales consecutivos. Se midió la concentración de estradiol y progesterona de 16 muestras de sangre de cada voluntaria (8 por ciclo) y se dividió el ciclo en 5 fases. Se obtuvo el promedio de la ingestión de energía y sus fuentes por Kg de peso corporal para cada fase. El consumo de energía (31.5 ñ 1.4 y 31.6 * 1.6 kcal/kg) para ada ciclo fue significativamente menor (por < 0.05) en la fase ovulatoria comparado con las demás y coincidió con el pico mñaximo de estradiol observado (219.8 ñ 27.8 y 238.3 ñ 19.4 pg/ml en cada ciclo respectivamente); este resultado apoya la hipótesis derivada de modelos animales en que se plantea que losestrógenos son supresores del hambre, se concluye que las variaciones hormonales del ciclo menstrual influyen en la ingestión de alimentos.