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Biomedical subjects

R L Butcher

Publications and source records attributed to R L Butcher.

At least 37 records · Page 2Linked to original sources
PubMed1984

Patterns of follicular growth during the four-day estrous cycle of the rat.

Female Sprague-Dawley rats underwent laporatomy during metestrus at 70 to 75 days of age or remained untreated to study the effects of surgical stress on follicular growth. Groups of rats were killed on each day of a 4-day estrous cycle, serial sections of the ovaries were prepared histologically and the number and size of follicles with one or more complete layers of cuboidal granulosa cells were determined. Since no differences due to surgery were found, the data were pooled by day of the estrous cycle (17 or 18 rats/day of cycle) for characterization and comparison of size distribution of follicles on different days of the estrous cycle. Follicles were classified as atretic or healthy and divided into groups by increments of 20 micron of diameter for graphing. Data were analyzed by analysis of variance and least squares means. Significant differences were found in the distribution of both healthy and atretic follicles among days of the estrous cycle. At least 21 follicles/ovary were recruited from less than 260 micron into greater than 260 micron in diameter between proestrus and estrus, and the follicles for ovulation were selected by diestrus. A greater number of growing follicles of 70 to 100 micron in diameter were present at diestrus. From the disappearance of follicles greater than 260 micron between estrus and proestrus, it appears that atresia is a very rapid process.

Animals↗
PubMed1983

Role of age and length of oestrous cycle in alteration of the oocyte and intrauterine environment in the rat.

Zygotes were transferred, on the day of fertilization, from young and old rats with 4- or 6-day oestrous cycles into the ovarian bursa of young recipients with 4-day cycles, and zygotes from young rats with 4-day cycles were transferred into young and old recipients with 4- or 6-day cycles. Young rats with 4-day cycles served as controls for both donors and recipients. An increase in length of cycle or maternal age of donor caused an increase in unfertilized and/or abnormal eggs at the pronuclear stage (non-transferred zygotes). Increased age of donor or length of cycle decreased the implantation rate observed on Day 11 of pregnancy. Likewise, increased age of recipient or length of cycle decreased implantation rate observed on Day 11 of pregnancy. The increase in both age and length of cycle of donor or recipient caused the greatest decline in implantation rate and percentage of normal embryos observed on Day 11 of pregnancy.

Animals↗
PubMed1982

Decreased amount of ovarian tissue and maternal age affect embryonic development in old rats.

The effects of addition and/or reduction of ovarian tissue and maternal age on ovulation rates (number of corpora lutea) and embryonic development were evaluated in old, regularly cycling rats on Days 4 and 11 of gestation. Young and old control rats and old rats which were either unilaterally ovariectomized (ULO), intact with 2 additional ovaries transplanted under the kidney capsule or ULO with 2 additional ovaries transplanted under the kidney capsule were mated on proestrus of a 4- or 5-day cycle between the 3rd and 9th postoperative cycle. The percentages of normal embryos on Days 4 and 11 of gestation were decreased (P less than 0.05) in the ULO rats, while on a per ovary basis the ovulation rate and ovarian weight were significantly increased in all the ULO rats compared to the old intact rats. An increase in abnormal and retarded embryos each contributed to this decreased percentage of normal Day 4 and Day 11 embryos in the ULO rats (P less than 0.05). Transplantation of ovarian tissue into old intact and ULO rats did not affect either the ovulation rate or the percentage of normal embryos and did not reverse the detrimental effects of unilateral ovariectomy. This could be due to inadequate stimulation or function of the ovarian tissue remaining in the transplants and may arise from a smaller vascular bed and limited blood flow to the transplants. Although regularly cycling young and old control rats had similar ovulation rates, the old control animals had a decreased percentage of normal embryos on Day 11 of gestation, but not on Day 4 of gestation, compared to the young control rats. This decrease in percentage of normal Day 11 embryos in the old intact rats was due mainly to an increase in retarded rather than abnormal embryos. From this study, it is concluded that unilateral ovariectomy of old cycling rats was detrimental to embryonic development. A similar, but more gradual decrease in functional ovarian tissue with aging, could cause the increased incidence of anomalies in embryos of older females.

Aging↗
PubMed1981

Introductory remarks: environmental and endogenous hazards to the female reproductive system.

The toxic action of environmental chemicals on reproduction and the toxiclike effects of ovarian hormones have been shown by numerous investigators. Some toxic effects of environmental chemicals on reproduction are through their action on hormonal secretion. Such effects on the endocrine system could provide additional approaches to investigations of toxicity of compounds. A better understanding of interactions of environmental chemicals with the endocrine system is needed. Therefore, it becomes important for a greater exchange of information and more interaction between toxicologists and endocrinologists.

Animals↗