Since cardiac function is depressed in males but not in proestrus (PE) females following trauma-hemorrhage (T-H), we examined whether different estrus cycles influence cardiac function in female rats under those conditions. We hypothesized that females in the PE cycle only will have normal cardiac function following T-H and resuscitation. Sham operation or T-H was performed in five groups of ra...

Genetic improvement in reproductive efficiency through selection is difficult because many reproductive traits are binomial and have low heritabilities. Before genetic markers can be generated for fertility in cows, greater characterization of reproductive phenotypes is needed to understand the components of the trait. The current study tested the hypotheses that: 1) breeds vary in postpartum i...

McKenzie’s laboratory (U. MO; 1930s) described the estrous cycle of domestic animals. Brownell (Cornell; 1936) reported AI and bull bred pregnancy rates were similar. Between 1938 (first, EJ Perry, NJ) and 1940, 54 AI organizations in 21 states were formed. Ulberg, Christian and Casida (1951) controlled time of ovulation in cows with progesterone (P) injected daily. Trimberger and Hansel (1955)...

A study was conducted to determine the effect of charcoal-extracted, bovine follicular fluid (CFF) on plasma follicle stimulating hormone (FSH) and luteinizing hormone (LH) concentrations, the interval from luteolysis to estrus, and subsequent luteal function in heifers. Fifteen Angus, Simmental and Hereford heifers were allotted by age, weight and breed to a control (C, n = 8) or a CFF (n = 7)...

BACKGROUND Galectin-3 (Gal-3), a β-galactoside-binding lectin, is a multifunctional lectin that involves in a number of critical biological processes. OBJECTIVE The purpose of this study was to investigate the expression pattern of Gal-3 in mouse endometrium during estrus phase of estrous cycle and pre-implantation. MATERIALS AND METHODS In this experimental study 42 NMRI female mice were d...

Domestic dogs are monoestrous, typically non-seasonal, polytocous, spontaneous ovulators and have a spontaneous luteal phase slightly longer (by approx 5 day) than the 64±1day luteal phases of a 65±1day pregnancy, a phase followed by an obligate anestrus before the next 2-3 week "heat" (proestrus-estrus). The resulting inter-estrus intervals of 5-12 months are variable among bitches, commonly 6...

In a previous study (1) during the investigation of the mutually reinforced instrumental sexual rqponses in rats a positive correlation has been found between the male and female response latencies. The purpose of the present work was to investigate whether this correlation is related to the mating behavior. Mutually reinforced instrumental responses, rewarded by contact with an animal of the o...

Spine density in the hippocampus changes during the estrus cycle and is dependent on the activity of local aromatase, the final enzyme in estrogen synthesis. In view of the abundant gonadotropin-releasing hormone receptor (GnRH-R) messenger RNA expression in the hippocampus and the direct effect of GnRH on estradiol (E2) synthesis in gonadal cells, we asked whether GnRH serves as a regulator of...

Background: Rodents with short reproductive cycle length are the best model for investigation of physiology and molecular aspects of reproductive biology. This study aimed to establish a correlation between histological changes of uterus and ovaries with the vaginal smear. Materials and Methods: 6-8 weeks old virgin Female NMRI mice were submitted to the vaginal smear collection and observed us...

Administration of the direct acting carcinogen N-methyl-N-nitrosourea (NMU) to 50-55-day-old virgin female rats on different days of the estrous cycle yields differential breast tumor biology (T. A. Ratko and C. W. Beattie, Cancer Res., 45: 3042-3047). One basis for these estrous cycle-dependent differences may be the duration of cell cycle stages of susceptible structures such as mammary termi...