Involvement of luteinizing hormone in the implantation process of the rat

The use of specific anti-FSH and anti-LH substances has shown that LH is the only pituitary gonadotrophin involved in the implantation process. Using different dosages of LH antiserum at different time intervals, it has been possible to arrive at a minimum effective dose (0.05 ml) which, when given on the 4th day at 10.00 hours, results in inhibition of implantation on the 8th day. We have shown that, at this dose, the antiserum is mainly inhibiting the oestrogen surge. It is proposed that an LH surge precedes an oestrogen surge on Day 4 of pregnancy

Need of luteinizing hormone for early pregnancy in the golden hamster (Mesocricetus auratus)

Administration of LH antiserum to intact pregnant hamsters on any day from Days 6 to 11 of pregnancy resulted in termination of gestation. Following LH antiserum injection, the ovarian weights were markedly reduced

CD146, a novel target of CD44-signaling, suppresses breast tumor cell invasion.

We have previously validated three novel CD44-downstream positively regulated transcriptional targets, including Cortactin, Survivin and TGF-β2, and further characterized the players underlying their separate signaling pathways. In the present study, we identified CD146 as a potential novel target, negatively regulated by CD44. While the exact function of CD146 in breast cancer (BC) is not completely understood, substantial evidence from our work and others support the hypothesis that CD146 is a suppressor of breast tumor progression. Therefore, using molecular and pharmacological approaches both in vitro and in breast tissues of human samples, the present study validated CD146 as a novel target of CD44-signaling suppressed during BC progression. Our results revealed that CD44 activation could cause a substantial decrease of CD146 expression with an equally notable converse effect upon CD44-siRNA inhibition. More interestingly, activation of CD44 decreased cellular CD146 and increased soluble CD146 through CD44-dependent activation of MMP. Here, we provide a possible mechanism by which CD146 suppresses BC progression as a target of CD44-downstream signaling, regulating neovascularization and cancer cell motility

Hormonal control of gestation in the intact rat

Administration of specific and wellcharacterized rabbit antisera to ovine luteinizing hormone (LH) to pregnant rats, before day 12 of gestation, resulted in vaginal bleeding followed by resorption of fetuses. This effect of the antiserum could not be reversed by the administration of either ovine prolactin or extracts of day 12 rat placentae. Homotransplantation of 2 pituitaries under the kidney capsule also did not reverse this effect. Whereas 0.25-5 μg estradiol-17β was ineffective, 4 mg of progesterone could overcome the effects of the antiserum. Deprivation of LH even for 2-8 hr was injurious to fetal growth. These effects of the antiserum could be reversed by the simultaneous administration of LH. Thus, evidence has been presented to show that LH maintains pregnancy up to day 12 by stimulating steroidogenesis. Of the 3 gonadotropins (LH, prolactin and FSH) tried, administration of LH during the second half of pregnancy resulted in postponement of parturition. Similar results were obtained with the administration of progesterone but not with 20α-hydroxypregn- 4-en-3-one (20α-OH-P) or estradiol. Based on these results, an integrated model for the hormonal control of pregnancy in the intact rat has been presented and the role of LH and prolactin in this process has been discussed

Effect of anti-luteinizing hormone serum on the ovulation of rats

In the cyclic female albino rat, a release of pituitary luteinizing hormone (LH) occurs on the afternoon of proestrus. This apparently induces ovulation, for ova are seen in the Fallopian tube 12 h later. Similarly, it is well known that in immature rats primed with pregnant mare serum gonadotrophin (PMS), ovulation can be induced by the administration of human chorionic gonadotrophin (HCG) or LH, the ova being seen in the Fallopian tube 12 h later. No information is available, however, about the mode of action of LH, released or administered, in bringing about ovulation. We have approached this problem by blocking the action of the ovulating hormone (LH) at various times after administration

Purification and properties of the follicle-stimulating hormone inhibitor obtained from the urine of the bonnet monkey

The follicle-stimulating hormone (FSH) inhibitor in monkey urine was purified by selective extraction of the crude extract with acetate buffer, ammonium sulphate precipitation and DEAE-cellulose chromatography. The purified inhibitor was free of luteinizing hormone activity. It behaved as an apparently homogeneous protein. The inhibitor contained about 20% carbohydrate (hexoses, hexosamines, fucose and sialic acid). Thin-layer gel filtration indicated a molecular weight of about 65,000. The inhibitor was labile to heat treatment, exposure to extremes of pH and denaturing agents. The inhibitor effectively neutralized the biological activity of FSH preparations from human, monkey, horse, pig, sheep and rat pituitary glands, pregnant mare serum gonadotrophin and human pituitary urinary gonadotrophin

Comparative mparative effects of antiserum to luteinizing hormone on pseudopregnancy and pregnancy induced in the same rat

The comparative role of luteinizing hormone (LH) in maintaining pregnancy and histamine-induced decidualization in the rat was studied with the help of a new system, wherein the above two states could be brought about simultaneously in the same animal, but in different uterine horns. Specific and well-characterized LH antiserum, administered daily, both during the pre-trauma (days 1-4) and post-trauma (days 5-8) periods, resulted in the termination of pregnancy and inhibition of decidualization. This antiserum effect could be reversed by suitable steroid therapy. Results suggest that the antiserum blockade of ovarian steroidogenesis continued even after cessation of its treatment. Early pregnancy and decidualization seem directly comparable in that both are dependent upon LH to stimulate the ovarian synthesis of much-needed progesterone and estrogen

Initiation of menstrual cyclicity and deciduomal reaction in the Bonnet monkey (Macaca radiata)

Decidualization has been induced in immature and acyclic mature bonnet monkeys by following a 30-day estrogen-progesterone combined therapy, traumatization being achieved on day 16 of treatment. This treatment led to an increase in the weight and glycogen content of the uterus. Histological examination of the uterus of traumatized animals revealed typical decidual cell pockets resembling a plaque reaction. Regular menstrual cyclicity has been induced in bonnet monkeys, which tend to show an amenorrheic behaviour soon after capture and transfer to the laboratory, by following a combination of estrogen and progresterone therapy