Effect of undernutrition on uterine progesterone and oestrogen receptors and on endocrine profiles during the ovine oestrous cycle

Abstract

In the present study, it was investigated whether undernutrition affected the binding capacity, immunoreactivity and mRNA expression for uterine oestrogen and progesterone receptors (ER and PR, respectively) in sheep, as well as whether the responses were associated with changes in plasma concentrations of progesterone (P4), oestradiol (E2), glucose, fatty acids, insulin, leptin and insulin-like growth factor (IGF)-I during the oestrous cycle. Twenty ewes were fed either 1.5 (C) or 0.5 (L) times their maintenance requirements and were killed on Day 5 or 14 of the cycle (Day 0 = oestrus). Compared with Group C, Group L had higher concentrations of non-esterified fatty acids and lower concentrations of insulin, leptin and IGF-I. Group L also had higher plasma concentrations of P4 during the final days of the luteal phase. At oestrus in both treatment groups, there were peaks in the concentrations of glucose, insulin and IGF-I. For ER and PR, transcript expression, binding capacity and immunoreactivity were higher on Day 5 than on Day 14 of the cycle. The binding capacities for ER and PR were lower in Group L than in Group C on Day 5. Group C showed more immunoreactive staining for ER than did Group L in two of five cell types, whereas no effect of treatment was observed for PR immunoreactivity. There was more PR mRNA in the uterine horn contralateral to the corpus luteum in Group C than in Group L ewes. We conclude that undernutrition impairs steroid receptor expression and binding capacity. This may alter the uterine environment and help explain the reductions in embryo survival.

Effect of exogenous melatonin on embryo viability and uterine environment in undernourished ewes

“…Our previous studies (Abecia et al, 1997(Abecia et al, , 1999Sosa et al, 2006Sosa et al, , 2009Vázquez et al, 2009Vázquez et al, , 2010a demonstrated that mature ewes subjected to a degree of undernutrition similar to that of the present experiment for 3-4 weeks exhibited a similar significant reduction in LW and BC. Unexpectedly, and in contrast with those works, the present study had no remarkable effect of undernutrition on the majority of the variables studied, except for a decrease of viability rate in recovered embryos at Day 5 after estrus.…”

The use of a ‘first-wave’ model to study the effect of nutrition on ovarian follicular dynamics and ovulation rate in the sheep

“…However, the fact that ewes maintained live weight and BC after being moved into the animal house suggests that they were not greatly affected by stress. High-BC ewes had lower glucose than low-BC ewes, as observed by Sosa et al (2006) in their 'well-nourished' and 'undernourished' ewes, but this is consistent with their higher concentrations of insulin, a factor that would drive glucose uptake. The tissues of high-BC ewes, including their ovarian follicles, would have been using more glucose perhaps growing faster, thus helping to explain the increased frequency of twin ovulations.…”

“…carry-over effects). Although the metabolic hormones were not measured during pre-experimental period, we would expect glucose and metabolic hormone concentrations to have been affected by the level of nutrition (Sosa et al 2006). Moreover, long-term effects of the metabolic status have been documented, with individual animals showing different responses to the same nutritional stimulus, a phenomenon that we have termed 'metabolic memory' (Blache et al 2007).…”

The Normal Genital Tract of the Female California Sea Lion (Zalophus californianus): Cyclic Changes in Histomorphology and Hormone Receptor Distribution

“…Significantly lower serum progesterone and estradiol concentrations have been noted in starved rats when compared with nonstarved rats (Baranowska et al, 2001). Lower ERa and PR expression was noted in malnourished ewes when compared with ewes fed maintenance feed requirements (Sosa et al, 2006). The underweight sea lions evaluated had ER a and PR scores similar to animals with normal body condition scores that died during the same time period, indicating that if malnutrition affected hormone receptor expression the effect was likely not detected.…”