Tsuneharu Sato

Follicle stimulating hormone and prolactin release induced by prostaglandins in rat.

Abstract Ten to 60 minutes following a single i.v. injection of PGE2 (500 μg/rat) into male rats of 30 to 35 days of age FSH concentration in the serum was raised significantly. The rise in FSH was maintained from 10 to 60 minutes after treatment, then at 90 minutes FSH had declined and was not significantly different from that of the control before treatment. Prostaglandin E1, E2 or F2α (670μg/rat) significantly increased the serum prolactin level 10 to 60 minutes after a single i.v. injection in spayed rats primed with estrogen and progesterone. And, rats primed with estrogen and progesterone. And, increases in prolactin in the serum were observed with as little as 2μg of PGE1 or E2, and 20μg of PGF2α. Twenty μg of PGE2, and 200μg of PGE1 or F2α gave the maximum stimulation. These results indicate that release of pituitary hormones is affected by prostaglandins. Prostaglandins (PGs) are widely distributed in mammalian tissues, and they have been reported to have an almost equally wide variety of endocrine and metabolic effects. It was recently postulated that PGs may be involved in the process of ovulation because ovulation was blocked by inhibitors of PG synthesis (1–5).

A clinical and metabolic study of masculinizing arrhenoblastoma

A patient with virilizing arrhenoblastoma was investigated clinically and evidence of estrinization was noticed. Urinary excretions of FSH, estrogens, 17-KS, 17-OHCS, pregnanediol, and pregnanetriol were assayed. Dexamethasone suppression and ovarian stimulation were carried out and a differential diagnosis of the hirsute female was undertaken. Chromosomal studies were carried out on peripheral blood and revealed a normal female karyotype (46/XX). Incubation studies with dehydroepiandrosterone-4-C 14 and Δ 4 -androstenedione-4-C 14 as substrate revealed evidence of testosterone production. Almost all of Δ 4 -androstenedione was converted to testosterone, and the residue was very low. The presence and overproduction of testosterone are significant factors to be considered in order to explain the high degree of masculinization in the cases of arrhenoblastoma.

The induction of abortion and menstruation by the intravaginal administration of prostaglandin F2α

The efficacy of intravaginal administration of prostaglandin F2 alpha (PGF2alpha) in induction of abortion was determined in a clinical trial of 16 gravidas aged 21-38, parity 0-4, between the 6th-11th weeks of pregnancy. PGF2alpha tablet (50 mg) was inserted into the posterior fornix of the vagina and repeated at 1-2 hour intervals; dose range varied from 50-250 mg. Slight to severe labor-like pain was felt by all patients in the lower abdominal region 20 minutes-4 hours after PGF2alpha administration. Vaginal bleeding occurred within 30 minutes-8 hours. In all but 1 case, the fetus and the villi were expelled broken into small pieces. All 16 patients aborted, 7 completely and 9 incompletely. This form of administration is deemed efficacious as 3 patients aborted completely within 5 hours and 4 aborted completely between 15-18 hours. Bleeding in most cases occurred following the onset of abdominal pain, 30 minutes-8 hours after treatment. In another clinical trial, the efficacy of intravaginal administration of PGF2alpha in inducing menstruation was tested in 10 volunteers aged 31-40. Either 50 or 25 mg PGF2alpha tablets were used. The patients recorded their basal body temperature (BBT) every morning. Menstruation was successfully induced in 6 of 10 patients. 6 patients treated 2-3 days before the expected date of menstruation had menstrual-like bleeding 1-9 hours after PGF2alpha administration. 3 patients treated 5, 7, and 13 days (a day before BBT shift) before the expected date of menstruation did not have vaginal bleeding. 1 patient, with monophasic BBT who was treated 3 days before the expected menstruation, did not have menstrual bleeding. Amount of induced flow was more or less the same in most patients; duration of flow was normal in all cases. The mechanism of action of PG in menstruation induction is not known. The authors speculate that PGF2alpha mechanically stimulates separation of the superficial endometrium from the remainder of the uterine wall when the endometrium is in the premenstrual state. Side effects noted were nausea, diarrhea, pyrexia, slight flushing of the face, and headache.

Changes in LH-releasing hormone content of the hypothalamus and electron microscopy of the anterior pituitary after prostaglandin E2 injection in rats

The purpose of this study is to present evidence that prostaglandin (PG) E2 stimulates a release of luteinizing hormone-releasing hormone (LH-RH) from the hypothalmus. In experiment 1, 72 hours after estrogen and progesterone treatment, a solution of 700 mug of PGE2 was injected into the jugular vein. Blood samples for plasma LH and the hypothalamus for LH-RH assay were collected before and 5, 10, and 30 minutes after PGE2 injection and subjected to radioimmunoassay. The total LH-RH content of the hypothalamus decreased from 20.4 to 15.3 ng. at 5 minutes after PGE2 and had returned to the pretreatment level by 30 minutes after PGE2 administration. On the other hand, plasma LH levels increased at 5 minutes, reached a peak at 10 minutes, followed by a decline at 30 minutes after PGE2 injection. In Experiment 2, 10 and 30 minutes after a single injection of PGE2 or synthetic LH-RH, the anterior pituitary were excised for an electromicroscopic study. Ten minute after PGE2, an enlarged Golgi apparatus, well-developed rough endoplasmic reticulum, and decreased secretory granules were observed in pituitary gonadotropins as compared with the control group. These changes were more conspicuous in the pituitaries obtained 30 minutes after PGE2. In Experiment 3, plasma LH levels were determined serially before and 10, 30, 60, and 90 minutes after a single injection of PGE2, LH-RH, or saline. There is a striking resemblance between the PGE2- and LH-RH-treated groups. Plasma LH levels in both these groups reached a peak at 10 minutes and started to decline 30 minutes after PGE2 or LH-RH administration. Our findings would indicate that PGE2 stimulates LH-RH secretion from the hypothalamus.

Plasma progesterone and prostaglandin F2α levels during the insertion of prostaglandin F2α vaginal tablet

Abstract Prostaglandin F2α (PGF2α) tablet was inserted into the vagina of three female volunteers during the luteal phase of their cycle, and of three early pregnant women of 6 to 10th week gestation. No effect was observed on peripheral plasma progesterone level in the cases of induction of menstruation, however, vaginal bleeding occurred in all three cases. For the induction of abortion, plasma progesterone levels decreased slightly in a few hour after administration of PGF2α. Complete abortion in a case and vaginal bleeding in two cases also occurred. The data obtained in this study indicate that the vaginal administration of PGF2α does not exhibit a luteolytic effect and exerts a stimulating effect on the myometrium.

Correlation between cyclic AMP and LH release following prostaglandin E2 administration.

Five min following a single iv injection of PGE2 into ovariectomized mature rats pretreated with estrogen and progesterone, plasma LH and plasma and pituitary cyclic AMP levels were raised significantly. A close correlation was observed between increased pituitary cyclic AMP contents and release of plasma LH. The average level of cyclic AMP in the anterior pituitary and plasma cyclic AMP increased significantly, while the circulating plasma LH level was not changed at 1 min after PGE2 injection. Plasma LH le-el increased at 2 min after PGE2 and reached a maximum level at the above-mentioned time. This is consistent with hypothesis that increased release of hormone is a consequence of increased pituitary cyclic AMP content.