Antiprogestagen RU486 prevents the LH-dependent decrease in the serum concentrations of inhibin in the rat

1. In the rat, the LH-dependent ovarian progesterone rise mediates several actions of the primary surge of LH on the ovary. This experiment was aimed at elucidating the effects of the antiprogestagen RU486 on the LH- dependent decrease in both the serum concentrations and the ovarian content of inhibin. 2. All rats in this experiment were treated with an antagonist of LHRH (1 mg/200 μl saline at 0800 b in proestrus) to supress the endogenous release of LH. One group of rats received 32 μg LH/250 μl saline at 1200h in proestrus. Other group was given 4 mg RU486/200 μl oil at 0800 h in proestrus. The third group was injected with both RU486 and LH. Rats from the control group were injected with 250 μl saline and 200 μl oil. Animals were decapitated at 1700 h in proestrus and trunk blood and ovaries collected to determine the serum concentrations of LH, FSH, progesterone, 17β-estradiol and inhibin as well as the ovarian content of inhibin. 3. The ovulatory dose of LH in LHRHα-treated rats decreased both the serum concentrations and the ovarian content of inhibin and increased the serum concentrations of FSH. The administration of RU486 blocked the effect of LH on the serum concentrations of inhibin but not that on the ovarian content of inhibin. 4. Since the antiprogestagen RU486 blocked the effect of LH on the serum concentrations of inhibin, we conclude that ovarian progesterone, besides mediating the effects of the primary LH surge on the ovulatory process and luteinization, participates in the LH-dependent drop in the serum concentrations of inhibin in proestrous afternoon

Association of candidate gene polymorphisms with chronic kidney disease : Results of a case-control analysis in the NEFRONA cohort

Chronic kidney disease (CKD) is a major risk factor for end-stage renal disease, cardiovascular disease and premature death. Despite classical clinical risk factors for CKD and some genetic risk factors have been identified, the residual risk observed in prediction models is still high. Therefore, new risk factors need to be identified in order to better predict the risk of CKD in the population. Here, we analyzed the genetic association of 79 SNPs of proteins associated with mineral metabolism disturbances with CKD in a cohort that includes 2,445 CKD cases and 559 controls. Genotyping was performed with matrix assisted laser desorption ionization-time of flight mass spectrometry. We used logistic regression models considering different genetic inheritance models to assess the association of the SNPs with the prevalence of CKD, adjusting for known risk factors. Eight SNPs (rs1126616, rs35068180, rs2238135, rs1800247, rs385564, rs4236, rs2248359, and rs1564858) were associated with CKD even after adjusting by sex, age and race. A model containing five of these SNPs (rs1126616, rs35068180, rs1800247, rs4236, and rs2248359), diabetes and hypertension showed better performance than models considering only clinical risk factors, significantly increasing the area under the curve of the model without polymorphisms. Furthermore, one of the SNPs (the rs2248359) showed an interaction with hypertension, being the risk genotype affecting only hypertensive patients. We conclude that 5 SNPs related to proteins implicated in mineral metabolism disturbances (Osteopontin, osteocalcin, matrix gla protein, matrix metalloprotease 3 and 24 hydroxylase) are associated to an increased risk of suffering CKD

Association of a single nucleotide polymorphism combination pattern of the Klotho gene with non-cardiovascular death in patients with chronic kidney disease

Chronic kidney disease (CKD) is associated with an elevated risk of all-cause mortality, with cardiovascular death being extensively investigated. However, non-cardiovascular mortality represents the biggest percentage, showing an evident increase in recent years. Klotho is a gene highly expressed in the kidney, with a clear influence on lifespan. Low levels of Klotho have been linked to CKD progression and adverse outcomes. Single nucleotide polymorphisms (SNPs) of the Klotho gene have been associated with several diseases, but studies investigating the association of Klotho SNPs with noncardiovascular death in CKD populations are lacking. The main aim of this study was to assess whether 11 Klotho SNPs were associated with non-cardiovascular death in a subpopulation of the National Observatory of Atherosclerosis in Nephrology (NEFRONA) study (n ¼ 2185 CKD patients). After 48 months of follow-up, 62 cardiovascular deaths and 108 non-cardiovascular deaths were recorded. We identified a high non-cardiovascular death risk combination of SNPs corresponding to individuals carrying the most frequent allele (G) at rs562020, the rare allele (C) at rs2283368 and homozygotes for the rare allele (G) at rs2320762 (rs562020 GG/AG þ rs2283368 CC/CT þ rs2320762 GG). Among the patients with the three SNPs genotyped (n ¼ 1016), 75 (7.4%) showed this combination. Furthermore, 95 (9.3%) patients showed a low-risk combination carrying all the opposite genotypes (rs562020 AA þ rs2283368 TT þ rs2320762 GT/TT). All the other combinations [n ¼ 846 (83.3%)] were considered as normal risk. Using competing risk regression analysis, we confirmed that the proposed combinations are independently associated with a higher fhazard ratio [HR] 3.28 [confidence interval (CI) 1.51-7.12]g and lower [HR 6 × 10- (95% CI 3.3 × 10--1.1 × 10-)] risk of suffering a non-cardiovascular death in the CKD population of the NEFRONA cohort compared with patients with the normal-risk combination. Determination of three SNPs of the Klotho gene could help in the prediction of non-cardiovascular death in CKD

lmmunohistochemical localization of prolactin in functioning and regressing corpus luteum of pituitary autotransplanted rats

In an attempt to shed light on the intimate mechanism by which prolactin (PRL) switches from supporting corpus luteum (CL) progesterone secretion (P) to promote structural regression of the CL, day 2 (metestrous) autopituitary transplanted (APTr) rats were used. In APTr rats the CL is under the only control of PRL since an almost complete absence of LH and FSH exist. The experimental group was given bromocriptine (CB-154: 0.4 mg/day) on days 12, 13 and 14 of the cycle and 0.25 ml of ethanol from day 15 to day 21. The control group was given CB-154 from day 12 to day 21. Rats were hemiovariectomized on day 12 to assess the morphological characteristics of the active CL. PRL and P were determined by RIA on days 12, 15 and 22. On day 12, both PRL and P levels were higher than 80ng/ml (luteotrophic action of PRL). On day 15, due to treatment with CB- 154, the levels of both hormones had fallen below 7 ng/ml (functional luteolysis). On day 22, PRL levels were again high ( > 50 ng/ml) in the shortly CB-154-treated rats and low ( < 5 ng/ml) in the controls; the P levels were lower than 5 ng/ml in both groups. PRL-induced structural luteolysis in the experimental group (hyperprolactinemic) was assessed by the structural characteristics and by the CL weight loss on day 22 in comparison with that exhibited by control rats. The immunohistochemical staining of both endogenous and total PRL in the lutein cells showed that the internalization of PRL is not modified by the functional state of the CL, nevertheless the intracellular redistribution of the internalized hormone varied in relation with the PRL action on the CL (luteotrophic, day 12vs luteolytic, day 22).These results seem to indicate that intracellular mechanisms rather than receptor content determine CL response to PRL

Morphological effects of oestradiol-17ß‚ and selective oestrogen receptor a and ß agonists on luteinising hormone-secreting

Summary. To investigate the role played by the different rat gonadotroph oestrogen receptor (ER) pools in the effects of oestradiol-17ß (E2) on gonadectomy cells, two-week ovariectomised (OVX) rats were used. The basic experimental group of rats was injected with 3 mg of the selective ER modulator tamoxifen (TX) on days 15-20 after OVX. Groups of TX-treated OVX rats were additionally injected on days 18-20 after OVX with 10 µg oestradiol benzoate (EB), 1 mg of the selective ERα agonist propylpyrazole triol (PPT), or 1 mg of the selective ERß diarylpropionitrile (DPN). Negative and positive control groups were OVX rats injected over six days after OVX with 0.2 ml oil and EB, respectively. On day 21 after OVX, anterior pituitary glands were dissected out and divided into halves. One hemipituitary was processed for light microscopy and immunocytochemistry for ßLH subunit and progesterone receptor (PR), and the other hemipituitary for ultrastructural evaluation. Results showed that: gonadotrophs were the only pituitary cell type expressing PR; treatment with TX alone shrunk gonadectomy cells and induced both reorganization of membrane-enclosed intracellular organelles and PR expression, and treatment with DPN or EB, but not PPT, reduced the agonistic morphological effects of TX. Considering that TX activates nuclear ERα, the results indicate that activation of nuclear ERα is determinant for the reversal effects of E2 on gonadotrope morphology and PR expression, and the simultaneous activation of ERß modulates the action of ERα in an inhibitory fashion