Changes in pituitary hormone secretions and corpora lutea following PGF2alpha administration to PMS/hCG-stimulated rats.

Pseudopregnancy was induced in 26 day old female rats by giving 30 IU of PMS followed 56 hours later with 5 IU of hCG. Day 1 of pseudopregnancy was considered established 72 hours after PMS administration. Pseudopregnancy lasted 14 to 15 days. Ovarian weights increased for 4 to 8 times due to treatment. Histological examiniation of the corpora lutea (CL) of pseudopregnancy suggested luteolysis began on day 6 and extended to day 8. A "new" crop of CL appeared on day 9 suggesting the duration of pseudopregnancy was supported by more than one generation of CL or by CL maturing at different rates. Twice daily administration of 1 mg PGF2alpha on days 5 to 8 prevented the appearance of the "new" CL on day 9, and increased signs of luteolysis in the initially formed CL. Lower doses (0.01 and 0.1 mg, b.i.d., X 4 days) delayed the appearance of "new" CL until day 10. Blood samples withdrawn between 0930 and 1100 hours were analysed for FSH, LH and prolactin. Animals treated with 0.01 and 0.1 mg of PGF2alpha, b.i.d., X 4 days had increased LH values on day 8, thus the PG appeared luteotrophic. Rats treated with 1 mg of PGF2alpha, b.i.d., X 4 days had decreased LH values on day 7 and the CL showed subsequent luteolysis. FSH levels were relatively constant during pseudopregnancy. However, all doses of PGF2alpha reduced FSH levels on day 7. An associated decrease in uterine weight occurred, possibly due to reduced follicular development. Prolactin levels fell in response to PGF2alpha treatment which undoubtedly contributed to the observed luteolysis. The signs of early cessation of pseudopregnancy were: increased serum FSH on days 9 and 10; increasing uterine weight; and the reappearance of follicular growth. These data suggest that PGF2alpha reduced the duration of pseudopregnancy primarily by inhibiting the secretion of FSH, LH and prolactin.

Influence of quinestrol on th histology and phosphatase activity of the simian uterus.

PIP: The purpose of this study was to evaluate the endometrial acid and alkaline phosphatase activity in rhesus monkeys chronically treated for 24 months with 3 levels of quinestrol (17-ethynlestradiol cyclopentyl ether). The 3 levels were: 1) 4 animals, 4 mcg/kg;2) 3 animals, 20mcg/kg; 3) 4 animals 100 mcg/kg. There were 4 animals included as sesame oil controls. All monkeys receiving quinestrol had some degree of cystic endometrial hyperplasia, dose-related, ranging from trace, to weak, to moderate cystic endometrial hyperplasia for high dose animals. The treated monkeys also showed thickening of the glandular basement membrane and an increase in endometrial and myometrial collagen (fibrosis), also apparently dose-related. In the monkeys receiving quinestrol, glandular alkaline phosphatase activity was comparable to that of the follicular and early luteal animals while the acid enzyme activity resembled that found in early and late luteal controls. Frequency of menstrual cycles was reduced.^ieng

Influence of an oral contraceptive progestin-estrogen combination on simian uterine phosphatases.

PIP: 16 adult female rhesus monkeys received combined oral quingestanol acetate and ethinyl estradiol in a 10:1 ration, 4 received steroids in a 20:1 ration. After 6 cycles of 21 days on and 7 days off the uterine alkaline and acid phosphatases were analyzed histologically. Dose groups included: 4 monkeys given 4 mcg per kg ethinyl estradiol and 40 mg quingestanol acetate, 4 given 20 and 200, 8 given 10 and 100, 4 given 50 and 1000. Most monkeys were killed 8 days after the last dose. In the 6 controls glandular phosphatases were low in early follicular phase, highest in late follicular phase, and declining in the stratum functionale in luteal phase; also acid phosphatase appeared in the stromal cells with eccentric nuclei in luteal phase. 90% of the low and middle dose monkeys were in follicular phase and had normal menstrual cycles. Their alkaline phosphatase was greater in stratum functionale than in stratum basale, and the acid phsophatase resembled controls in follicular phase. Most monkeys given high doses were in luteal phase and their enzymes were correlated with cycle phase.^ieng