Changes in (3H)leucine incorporation into pineal proteins following estradiol or testosterone administration: involvement of the sympathetic superior cervical ganglion.

Pineal denervation by superior cervical ganglionectomy (Gx) decreased high affinity binding of estradiol (E2) to the pineal cytosol of female rats and of testosterone to the cytosol of male rats by 40 and 26% and by 75 and 80%, 5 and 14 days after sugery; hormone binding remained unchanged up to 24 h after surgery. Binding to the nuclear fraction decreased sigificantly by 2 weeks after incorporation of (3H) leucine into pineal proteins in Gx. A single injection of E2 (mug) to testosterone propionate (TP) (500 mug) failed to increase the Gx rats when injected 1 or 5 days after surgery. Significant increases were observed in sham-operated controls or in rats subjected to bilateral decentralization of ganglia; however on the 5th day an impairment was observed in hormone ability to enhance [3H]leucine incorporation in decentralized rats. The administration of isoproterenol 19 and 3 h before sacrifice replenished pineal-binding sites for E2 and testosterone in Gx rats, but failed to restore the responsiveness of denervated pineals to hormone administration. Moreover, E2 or TP treatment blocked the increase in labeled amino acid incorporation into proteins brought about by isoproterenol per se. The administration of propranolol 2 and 7 h after hormone injection decreased the ability of E2 and TP to enhance [3H]leucine incorporation by 55 and 41%, respectively. Tyrosine hydroxylase activity of the superior cervical ganglia decreased by 36 and 41% 6 h after E2 or TP administration, and by 43 and 47% after 3 daily injections of the hormones, whereas pineal tyrosine hydroxylase remained unchanged. Hormone treatment for 3 days increased the in vitro uptake of norepinephrine by the ganglia but did not affect uptake in the pineal gland. These data indicate that the integrity of neurons of the superior cervical ganglia is an absolute requirement for E2 and testosterone to enhance [3H]leucine incorporation into pineal proteins in rats.

The secretion of progesterone during the periovulatory period in women with certified ovulation.

A pre-LH peak rise of progesterone in peripheral blood has been found in 13 normal cycling women whose ovulation was confirmed by biopsy of the corpus luteum through serial determination of progesterone and LH performed every 8 h during the periovulatory period. The progesterone rise began as an average 22 h (16-40 h) prior to the LH peak. The maximal preovulatory rise took place 9.6 h (0-24 h) before the LH zenith, remaining low for approximately 17 h when an abrupt rise of progesterone took place. The progesterone peak was detected in the morning samples in 11 of 13 patients studied. The progesterone rise was always followed by an LH peak and the highest peak of progesterone was trailed by the highest LH peak in all the patients except one.

Daily variations of FSH, LH and testosterone response to intravenous luteinizing hormone-releasing factor (LRF) in normal men.

The responses of FSH, LH and testosterone to acute stimulation with synthetic LRF were studied in 6 healthy, fertile men aged 33.4 plus or minus 1.6 yr (X plus or minus SE). Fifty mug of LRF were given, iv at 0600 h, 1200 h, 1800 h and 0000 h, at 1-week intervals, to all 6 volunteers simultaneously. Blood samples were collected by venipuncture before (-5 and 0 min) and 8, 16, 32, 64 and 128 min after LRF injection. Plasma levels of FSH, LH and testosterone were determined by double antibody radioimmunoassay techniques. The responses of FSH and LH to LRF injection showed a clear difference at the times studied. Maximal values were obtained at 0600 h and 1800 h while the response at noon was not significant for LH and absent for FSH. Testosterone secretion showed a clear-cut response to LRF in all the subjects. At three of the four studied times (0600 h, 1800 h, 000 h) plasma testosterone was already increased at 8 min reaching its maximum at 16 min and persisted high until the end of the study. The noon response reached its maximum at the end of the test period. The daily variations of FSH and LH responses to acute LRF stimulation should be taken into consideration in clinical practive and the increment in testosterone secretion makes this test a useful indicator for androgenic testicular reserve.

Further evidence for histamine facilitating oestrogen action in the uterus.

The effect of doses of estradiol ranging from 0-0125 to 1-6 mug on the uterine weight of the spayed rat was studied 24 h after a single s.c. injection of the hormone. The lowest dose inducing a significant increase in uterine weight was 0-32 mug. When histamine dihydrochloride (50 mg) was simultaneously injected with the hormone, the effect of small doses of oestradiol (0-0125--0-2 mug) was significantly increased. When oestradiol and histamine were administered for 3 successive days, the uterine weight of animals receiving 0-0125 mug oestradiol, if compared with untreated controls, was increased only in the histamine-treated group. When 0-05 mug oestradiol was administered histamine did not modify the increase already produced by the hormone. Spermidine and burimamide, two substances structurally related to histamine, increased [3H]oestradiol uptake by the spayed rat uterus. The latter (an antihistamine drug acting on H2-receptors) as well as pyrathiazine (a histamine releaser having antihistamine properties) decreased the effect of histamine on oestradiol uptake whereas diphenhydramine (an antihistamine drug blocking H1-receptors) did not modify it. Pyrathiazine was itself able to diminish oestradiol uptake.

A direct effect of antiovulatory compounds on human testicular biosynthesis in vitro.

PIP: Human testes, removed in treating patients for prostatic carcinoma, were used. Tissues were homogenized and incubated in vitro with labeled progesterone and 2 different antiovulatories, lynestrenol (17alpha-ethin yl-17beta-hydroxy-estr-4-one) and MK 665 (17alpha-chloroethinyl-19-nor-4 ,9(10)-androstadiene-17beta-ol-3-one). Further biochemical procedures are described. Results show that the compounds added in vitro to the homogenates inhibited the conversion of progesterone to 17alpha-hydroxyprogesterone, 20alpha-hydroxy-4-pregnene-3-one, and androgens. It is thought that these 2 compounds exert a direct effect on the activity of 2 human testicular enzymes related to the biosynthesis of androgens and on the 20alpha-hydroxy steroid dehydrogenase. With the concentrations employed, no androgen biosynthesis was observed with the larger doses and only partial inhibition with the smaller doses. The action could be on the enzyme systems themselves or on the synthesis of the enzymes. Results are valid for in vitro conditions only.^ieng

On the mechanism of action of oral contraceptives. I. Effect of lynestrenol on ovum implantation and oviductal morphology in the rat.

PIP: 2 experiments on virgin female rats (average weight 200 gm) were performed to study the effects of small doses of lynestrenol on the early pregnancy of the rat. In both experiments, the rats were caged with a mate overnight and if, on the following morning, spermatozoa were found on the vaginal smear, that day became Day 1 of pregnancy. In Experiment 1, the test group (15) received .1 mg lynestrenol sc and the control group (14) 1 ml propyleneglycol on Days 2, 3, 4, and 5 of pregnancy. Experiment 2 differed in that the rats received 1 mg dosages of lynestrenol. On Day 7 of pregnancy, Experiment 1 rats were killed and their ovaries and genital tracts were examined. In Experiment 2, the rats were permitted to live until Day 23 to see if they would achieve full-term pregnancy. If delivery did not occur, they were killed (Day 25) and examined for fetuses. In Experiment 1, the dose did not significantly increase the number of lost ova (20% in controls), as indicated by the implanted embryos/recent corpora lutea ratio counted on Day 7. There was an increase in the number of ciliated cells in the epithelium and a diminution of the deciduoid tissue of the stroma. No histological changes were seen in the ovaries, embyros, or uteri. The 1 mg dosage of lynestrenol prevented pregnancy in all of the rats. Doses were smaller than those needed to inhibit ovulation, and the time of administration of the doses excluded any action on sperm transport, capacitation, or penetration. Lynestrenol would appear to act on the pregnant rat's genital tract, as oviducts displayed evidence of estrogen stimulation.^ieng

[Competition between estradiol and various progestogens at the level of the rat hypothalamus]. / Compétition entre l'oestradiol et différents progestagènes au niveau de l'hypothalamus du rat

PIP: Short-term cultures (32 hours) of rat hypothalamus were incubated with tritiated estradiol and either medroxyprogesterone, Ro 4-8347, norgestrel, or lynestrenol to find out whether the progestagens would compete for estrogen receptors. Each culture was preincubated for 8 hours in medium 199, washed, incubated for 16 hours with progestagen (preincubation experiment), and incubated a further 8 hours with labeled estrogen (control or preincubation experiment) or estrogen and the progestagen (simultaneous experiment). Ro 4-8347 (1,6-dehydro-6-chlororetroprogesterone) .6 ng/ml inhibited estradiol uptake when it was added before the estrogen. Lynestrenol and norgestrel displaced estradiol in simultaneous cultures only. Medroxyprogesterone reduced estradiol uptake when it was added both before and during the estradiol incubation.^ieng