Effect of Ovariectomy on Concentration of Progesterone in Blood Plasma and Urinary Estrogen Excretion Rate in the Pregnant Bovine

Psychoimmunological effects of dioscorea in ovariectomized rats: role of anxiety level

“…decreased levels of progesterone and estrogen [25], increased risk of cardiovascular disease [26], and enhanced rate of bone loss [27,28]. Although anxiety and depression are very common in menopausal women and elevation of anxiety levels has been reported in Long-Evans [38] and Wistar rats [29] after ovariectomy, the present study indicated that, compared to the sham-operated group, only half of OVX rats fell into the "high anxiety" group.…”

“…OVX rats were used as a menopausal animal model because the changes in biochemical and physiological function seen in these animals are comparable with those in menopausal women [24], i.e., decreased levels of progesterone and estrogen [25], an increased risk of cardiovascular disease [26], and an enhanced rate of bone loss [27,28], as well as an increased anxiety level [29]. The time spent in the open arm during the EPM test is used to evaluate unconditioned avoidance behavior as a measure of anxiety [30,31], while immobility, a despair behavior, in the forced swim test (FST) is used to measure learned helplessness as a model of depression [32].…”

Multilevel regulation of steroid synthesis and metabolism in the bovine placenta

“…Unlike humans and sheep, wherein the placenta replaces the CL as the major site of progesterone production relatively early in gestation (Moore et al, 1972;Simpson and MacDonald, 1981), the CL in the pregnant cow continues to produce progesterone and remains an important source of progesterone until near term (Estergreen et al, 1967;Chew et al, 1979), even though evidence suggests that luteal function and secretory capacity decline in late gestation (Shemesh et al, 1983). Although the bovine placenta is steroidogenically active at an early stage of gestation, its capacity to fully replace the CL in producing enough progesterone to maintain the pregnancy is restricted to the later stages of gestation, from about days 180 to 200 onwards (Erb et al, 1968;Chew et al, 1979); in experiments where the CL was removed and the pregnancy survived, the animals gave birth prematurely (Estergreen et al, 1967). Generally, the bovine placenta contributes less progesterone to the maternal circulation than does the placenta of ewes or women (Geisert and Conley, 1998).…”

“…Data on the mRNA levels of StAR, P450scc, and 3b-HSD during the first 4 months of gestation in cows (Veduzco et al, 2008), on the other hand, suggest that the maternal caruncles exhibit greater steroidogenic capacity than the foetal cotyledons in the first half of gestation. Regardless of whether the maternal caruncles or the foetal cotyledons produce more progesterone in the first half of gestation, there is insufficient progesterone produced from the placenta to sustain the pregnancy if the CL is lost during the first 5-6 months of pregnancy (Estergreen et al, 1967;Erb et al, 1968;Chew et al, 1979).…”

Dioscorea improves the morphometric and mechanical properties of bone in ovariectomised rats

“…OVX rats are used as a menopausal animal model because the changes in biochemical and physiological functions seen in these animals are similar to those in menopausal women,20 i.e. decreased levels of progesterone and oestrogen,21 an increased risk of cardiovascular disease22 and an enhanced rate of bone loss,7, 23 as well as increased anxiety levels 24. There are no published studies on the effect of dioscorea on the morphometric and mechanical properties of bone in OVX rats.…”