Studies on the oestrus cycle in the rat

  • 39 Pages
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  • English

Ohio State University , [Columbus]
Statementby Milton Oliver Lee.
LC ClassificationsMicrofilm 41414 (Q)
The Physical Object
Pagination39 p. in various pagings
ID Numbers
Open LibraryOL2018771M
LC Control Number90953797

The oestrous cycle in the rat ^tained in % methylene blue for 1 min. and rinsed in tap water. The smears were either examined wet, or dehydrated, cleared and mounted in Canada balsam. This technique stains acidophil cytoplasm red, and basophil cytoplasm by: Abstract and Figures The rat has been elected as the main animal model in several studies involving reproduction.

However, there are scarce and conflicting data related to its estrous cycle.

Description Studies on the oestrus cycle in the rat EPUB

The short length of the estrous cycle of rats makes them ideal for investigation of changes occurring during the reproductive cycle. The estrous cycle lasts four days and is characterized as: proestrus, estrus, metestrus and diestrus, which may be determined according to the cell types observed in t.

The short length of the estrous cycle of rats makes them ideal for investigation of changes occurring during the reproductive by: The oestrous cycle in the rat and its associated phenomena.

Series Title(s): Memoirs of the University of California Author(s): Long, J. (Joseph Abraham), There is a relationship between the electrical impedance of the vaginal mucous membrane and mucus and the various phases of the oestral cycle in animals. Daily measurement of the impedance in rats is an easy and rapid method for monitoring by: hypothalamus changes during the estrous cycle (Prescott, Scott & Hoebel, Moss, ).

Others were tmable to confirm such a relationship (Hitt & Gerall, Lenzer, Drewett & Herberg, ). In the present study the estrous cycle of the rat was used to study further some of the. Estrous cycle study was done in accordance with the method described by Marcondes et al.

[17] A volume of mL of % saline solution was gently introduced times into the vagina of the rats. leukocytes. The goal of this study was to revisit the literature about the rat estrous cycle and to perform a detailed quantitative and qualitative description of its phases and the transitional periods among them.

Vaginal smears were obtained twice daily for 20 days from Wistar rats and stained using Shorr method. Cells the. The rat estrous cycle averages 4 to 5 days in length, occurs throughout the year without seasonal influence in laboratory colonies, and occurs from pubertal onset until senescence, including during the postpartum period (Bennett and Vickery, ).The cycle consists of four stages: proestrus, estrus, metestrus, and diestrus (see Table ).

Based on vaginal smears, the duration of the individual components of the estrous cycle for rats with a four- or five-day cycle are proestrus, twelve to fourteen hours; estrus, twenty-five to twenty-seven hours; metestrus, six to eight hours; and diestrus, fifty-five to fifty-seven hours (Astwood, ; Hartman ; Long and Evans ; Mandl ).

Plasma vasopressin concentrations vary throughout the rat oestrus cycle. In order to determine the relationship of these fluctuations to fluid retention, studies were carried out in cycling female albino rats. The animals were housed in individual metabolism cages under 12 hourlight/12 hour dark regimen, with free access to food and water.

Abstract While an evaluation of the estrous cycle in laboratory rodents can be a useful measure of the integrity of the hypothalamic‐pituitary‐ovarian reproductive axis, it can also serve as a way of insuring that animals exhibiting abnormal cycling patterns are disincluded from a study. These were all part of John Calhoun’s experiments to study the effects of population density on behavior.

But what looked like rat utopias and mouse paradises at first quickly spiraled into out. morphological changes over the course of oestrous cycle, driven by cyclic fluctuations in several reproductive hormones.

Knowledge of the normal histological appearance of the reproductive tract at each stage of the oestrous cycle is essential when evaluating female reproductive tissues from TG studies for evidence of endocrine disruption.

Summary. The duration of the oestrous cycle in thirty-nine adult rats derived from ten litters was ± days. The variance in cycle length tended to be less within than between litter-groups (P ≏).

It was significantly less for individual rats than between individuals (P. From the onset of sexual maturity up to the age of 12 months, the mean cycle length in the female rat is 4 days (Long & Evans, ; Freeman, ; Mandl, ), and this short cycle length makes the rat an ideal animal for investigation of changes occurring during the reproductive cycle (Spornitz et al., ; Marcondes et al., ).

Multiple references regarding the cytology of the rat and mouse estrous cycle are available. Many contemporary references and studies, however, have relatively abbreviated definitions of the stages, are in reference to direct wet mount preparations, or lack comprehensive illustrations.

Before heat ( h) Hours from the start of estrus HoursHours 00 66 99 Egg released Life of egg ( h) Standing heat (18 h) After heat (10 h) Estrus in cow and associated featuredEstrus in cow and associated featured The Rodent Estrous Cycle: Characterization of Vaginal Cytology and Its Utility in Toxicological Studies Jerome M.

Goldman, Ashley S. Murr, and Ralph L. Cooper Endocrinology Branch MD, Reproductive Toxicology Division, National Health and Environmental Effects Research Laboratory. Oestrous Cycle in Septal Rat Females (i.e. pro-oestrus, oestrus and metoestrus) were equal in both septal and intact animals.

Mo difference was found between the rat stocks used. Similarly, the previous life history of the rats which had been housed either in a socially impoverished environment (i. single. Physiol. (I) I35, THEEFFECTOF THEOESTROUSCYCLEANDOF HORMONES ON THE COLLAGEN CONTENT OF THE UTERUS OF THE RAT BY MARGARET L.

HARKNESS, R. HARKNESS AND BRENDA E. MORALEE Fromthe Department ofPhysiology, University College London (Received 26 July ) In previous studies of various growth processes in adult tissues, collagen.

The estrous cycle in rodents occurs every 4–5 days throughout the year (Freeman, ).

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The sequential stages of proestrus (1 day), estrus (1 day), and diestrus (2 days) correspond functionally to the follicular, periovulatory, and luteal phases of the menstrual cycle in higher primates. DEVELOPMENTAL DYNAMICS provides a focus for communication among developmental biologists who study the progressive and dynamic emergence of form and function during embryonic development.

The journal is an international forum for the exchange of novel and substantive information on mechanisms that control development. We seek manuscripts presenting work done at all levels of.

Figure Legends Figure 1. Schematic of the rat four-day estrous cycle depicting relationship among vaginal cytology, serum estradiol, and serum LH (m = midnight). Figure 2. Photomicrographs (X) showing major changes in the vaginal smear during the estrous cycle in the rat.

The absolute number of cells may vary from sample to sample. Search the world's most comprehensive index of full-text books. My library. In this study, we assessed natural killer cell activity and host susceptibility to metastasis during the oestrous cycle in the Fischer inbred rat strain.

Females were inoculated intravenously with MADB tumour cells, a syngeneic mammary adenocarcinoma cell line that metastasises only to the lungs. when the females become receptive to the male. The classic stages of the rat oestrous cycle can be designated as oestrus (E), metoestrus (M), di-oestrus (D) and pro-oestrus (P).

The stages of the vaginal cell cycle will normally correlate with changes in. Female virgin rats on each day of the oestrous cycle (oestrus, dioestrus-1, diestrus-2, pro-oestrus) and pregnant rats on gestation day 16 were used in these studies. Following anaesthesia with an i.p.

injection of ketamine ( mg/kg) combined with xylazine ( mg/kg), the abdominal cavity was opened and the superior mesenteric artery. Hormones are commonly used to manipulate the estrous cycle. The major indications for hormonal control of estrus are to induce luteolysis, induce ovulation of a mature follicle, suppress estrus, induce cyclicity in anestrous animals, and superovulate cyclic animals.

Effective treatments for these manipulations vary among species. The oestrous cycle of the female rat lasts 4–5 days and is divided into four stages, characterized by changes in vaginal cytology and hormone levels. The stages of pro-oestrous and oestrous, which last about 12 h each, correspond to the luteal phase of the human menstrual cycle.

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The Rodent Estrous Cycle Rats and mice are spontaneous ovulators – i.e. they do not need the presence of males to induce ovulation. There is some evidence the stimulation from male rodents can induce and or/hasten ovulation, but it is not obligatory.The estrous cycle or oestrous cycle (derived from Latin oestrus "frenzy", originally from Greek οἶστρος oîstros "gadfly") is the set of recurring physiological changes that are induced by reproductive hormones in most mammalian therian s cycles start after sexual maturity in females and are interrupted by anestrous phases or by pregnancies.In Asian elephants, the estrus cycle has an overall duration of 12–19 weeks, the luteal phase extending between 4 and 15 weeks, and the follicular phase lengthening for 2–12 weeks.

In red-rumped agoutis, the estrus cycle lasts for 31 days, the follicular phase ranging from 6 .