Role of progesterone in mediating stress-related litter deficits in the golden hamster (Mesocricetus auratus)

Abstract

Primiparous females were mated to proven breeders and half received a subcutaneous implantation of a progesterone-filled silastic capsule on Day 3 which was removed on Day 14. The other half of the group received no treatment. Blood samples were taken from all individuals on Days 3, 7, 11 and 14. The females were paired for brief periods on Days 4, 5 and 6 with a conspecific matched for treatment group, age, weight and stage of pregnancy. Controls were exposed to a novel area instead of a conspecific. Within each of the pairs, one female was consistently dominant to the other. At parturition, all pups were counted, sexed and weighed. Among the untreated group, there were no significant differences between litter sizes or sex ratios (defined as percentage male) produced by control and dominant females. Subordinate females produced significantly smaller litters than control or dominant dams and significantly lower sex ratios than dominant dams. Subordinates produced fewer males than control or dominant dams, but there were no differences in the number of females produced. Among animals given progesterone implants, there were no significant reductions in litter size or sex ratio produced by subordinate dams compared with control or dominant dams. This study showed that female golden hamsters exposed to social subordination early in pregnancy produced smaller and more female-biased litters, and that these effects were accompanied by a significant reduction in circulating progesterone concentrations. When subordinate females were given supplementary doses of progesterone before exposure to stress, they did not show significant litter deficits.(ABSTRACT TRUNCATED AT 250 WORDS)

Effects of maternal exposure to social stress during pregnancy: consequences for mother and offspring

“…In hamsters, social stress exposure (social defeat by a dominant conspecific) during early pregnancy results in significantly smaller litter sizes and reduced birth weight for both male and female pups (Pratt & Lisk 1991). Moreover, there is a significant reduction in the number of males per litter, indicating selective resorption/spontaneous abortion of males in utero (Pratt & Lisk 1991). Similar effects on litter size have also been reported in mice exposed to psychosocial stress (exposure to a rat or rat odour) in early pregnancy (de Catanzaro 1988).…”

“…These effects of stress on pregnancy loss are associated with a significant reduction in circulating progesterone levels and can be prevented by exogenous progesterone administration (Pratt & Lisk 1991). Exposure to other types of stressors during early pregnancy has also been shown to reduce circulating progesterone levels in mice (Parker et al 2011), and in women low progesterone levels in early pregnancy can predict miscarriage (Arck et al 2008).…”

“…In rodents, prenatal stress is associated with negative pregnancy outcomes such as low birth weight, reduced litter sizes and lower survival rates (de Catanzaro 1988, Pratt & Lisk 1991, Brunton & Russell 2010, and in the adult offspring, it is associated with heightened anxiety (Fride & Weinstock 1988, Vallee et al 1997, Fan et al 2009, Brunton & Russell 2010, enhanced or prolonged hypothalamo-pituitary-adrenal (HPA) axis (Fig. 1) responses to acute stress (Takahashi & Kalin 1991, Weinstock et al 1992, McCormick et al 1995, Koenig et al 2005, Fan et al 2009, Brunton & Russell 2010, hypertension (Igosheva et al 2004), impaired glucose homoeostasis (Brunton et al 2013), insulin resistance (Nilsson et al 2001), diet-induced obesity (Nilsson et al 2001, Tamashiro et al 2009), impaired neural development (Lemaire et al 2000), cognitive deficits (Lemaire et al 2000, and abnormal social (Patin et al 2005, Lee et al 2007 and reproductive behaviours (Holson et al 1995, Frye & Orecki 2002.…”

The Contrasting Effects of Ad Libitum and Restricted Feeding of a Diet Very High in Saturated Fats on Sex Ratio and Metabolic Hormones in Mice1

“…Stress has previously been reported to influence the sex ratio of rodents [16][17][18]. Finally, we determined whether the sex ratio skewing effects of the VHF diet could be conferred through the breeder males, who were exposed to the diet while they were temporarily housed with the females during mating.…”

Influence of the number of suckling young and the feed level on foetal survival and growth in rabbit does

“…In simultaneously pregnant and lactating does, prolactin concentrations are higher and progesterone concentrations are lower than in non-lactating pregnant does (Mac Neilly and Friesen, 1978;Fortun et al, 1993). Prolactin might be involved in the higher foetal mortality observed in lactating does since, in the rabbit, this hormone is known to affect luteal function (Holt, 1989) and uterine activity (Chilton and Daniel, 1987 (Pratt and Lisk, 1991;Parr, 1992).…”