Seasonal changes of steroid levels in blood plasma of three phodopus species (Mammalia, Cricetinae)

Relationship between oxidative stress and circulating testosterone and cortisol in pre-spawning female brown trout

“…Glucocorticoids are involved in the mobilisation of energy during stress (e.g., Moore and Hopkins, 2009) and administration of these hormones affects the activity of important antioxidant enzymes such as superoxide dismutase (SOD, Goncharova et al, 2006) and, depending on the duration of treatment, can have significant effects on oxidative stress . Despite detailed evidence in the literature regarding changes in hormone levels during reproduction of vertebrates in general (Feoktistova et al, 2010;Horton et al, 2010;Mull et al, 2010) and salmonid fish in particular ( Fig. 1), the consequences of hormone variation for oxidative stress remain poorly understood.…”

On the winter enhancement of adaptive humoral immunity: hypothesis testing in desert hamsters (Phodopus roborovskii: Cricetidae, Rodentia) kept under long‐day and short‐day photoperiod

“…According to our observations in Trans-Altai Gobi Mongolia, reproduction is limited to the warm period of the year. Seasonally restricted reproduction is confirmed by the dynamics of sex hormone concentrations in hamsters kept outdoors year-round (Feoktistova & Meschersky 2005;Feoktistova et al 2010), as well as by the observation of seasonal variation in sex hormonal response to conspecific odors (Feoktistova & Naidenko 2006).…”

“…Severtsov Institute of Ecology and Evolution RAS, descended from the founders, caught in the Mongolian Trans-Altai Gobi Desert in the mid-1980s. Although the seasonality of breeding in a vivarium under standard conditions with a photoperiod of 14 h light : 10 h dark and a temperature of 23 ± 2 °C was lost over the years, once the animals were relocated outdoors, they soon demonstrated seasonal patterns of breeding (Feoktistova & Meschersky 2005;Feoktistova et al 2010;Vasilieva, unpubl. data).…”

Seasonal peculiarities of female hormonal response of females to conspecific chemical signals of the male in two species of the genus Phodopus

“…How ever, it is known that the attractiveness of the odor of male urine of the laboratory mouse of the lineage BALB/c during testing on females does not change throughout the year (Kaneko et al, 1980). At the same time, there are data that in the spring-summer period males and females of the Pennsylvanian vole Microtus pennsylvanicus produce odors attracting individuals of the opposite sex, and in the autumn-winter period, to the contrary, males do not demonstrate a preference for odors of conspecifics, while females are attracted by odor signals of other females (Leonard and Ferkin, 1999).The study of behavioral and hormonal responses of males of three species of feather legged hamsters to odors of urine, secretion of the midventral gland (MVG), and excreta of females demonstrated signifi cant seasonal differences in these responses (Feoktis tova and Naidenko, 2006, 2007;Feoktistova et al, 2010).The purpose of our study was to determine the pat tern of seasonal sensitivity of two species of hamsters of the genus Phodopus to natural excreta (urine and MVG) of conspecific males on the basis of measuring the level of sex steroids (progesterone, estradiol) and glucocorticoid (cortisol) after exposure to urine and secretion of MVG and comparison of the obtained results between the species.The problem of the hormonal response of females to chemical signals of conspecific males is rather poorly studied, but is very urgent. With reference to several species of mammals, it was shown that the administration of estradiol and progesterone causes in females an active search for partners (Lindsay and Fletcher, 1972).…”

“…The study of behavioral and hormonal responses of males of three species of feather legged hamsters to odors of urine, secretion of the midventral gland (MVG), and excreta of females demonstrated signifi cant seasonal differences in these responses (Feoktis tova andNaidenko, 2006, 2007;Feoktistova et al, 2010).…”