摘要:

The aim of the study was to determine the association between PRL responses to suckling and maintenance of postpartum amenorrhea among breastfeeding mothers. Three blood spot samples (5, 30, and 50 min following a timed nursing bout) were collected from 71 intensively breastfeeding Nepali women for PRL determination. Maternal age, BMI (weight/height2), menstrual status, caste, infant age, nursing bout length, and duration of supplementation were recorded at time of sample collection. Independent and pairedttests, linear regression analyses, and general linear models were used to evaluate differences between cycling (n=36) and amenorrheic (n=35) women and associations among variables. Logistic regression analyses were used to relate PRL measures to the odds of maintaining lactational amenorrhea.Amenorrheic breastfeeding mothers had higher (P<.001) PRL levels at all 3 collection times than cycling breastfeeding mothers, and PRL levels declined with time since birth (P<0.05). The odds (OR) of having ceased lactational amenorrhea was significantly higher (OR=5.0. 95% Cl=1.3–19.9) among mothers with lower PRL levels (≤10 ng/mL) at 50 min post-suckling, and PRL at 50 min showed a significant dose response relationship with menstrual status. The association between 50 min PRL levels and lactational amenorrhea appears to be independent of time postpartum, maternal age, BMI, nursing bout length, and duration of supplementation. Among intensively nursing women, maintenance of elevated PRL levels across the interbout interval increases the odds of maintaining lactational amenorrhea.

ISSN:0743-5800    

DOI:10.3109/07435809609030495

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

A 250 kDa secretory protein was isolated from the uterine luminal fluid (ULF) obtained from estradiol-treated ovariectomized rats. Antiestrogens blocked the production of this protein. The protein components were separated and purified by SDS-PAGE. Polyclonal antibodies were raised against the 250 kDa protein and used to identify the protein by Western blot. 17β-estradiol (E2) at a dose of 0.005 mg/kg/d administered sc for 3 days to ovariectomized rats stimulated a marked increase in the production of the 250 kDa protein. Anordiol at a low dose of 5 mg/kg/d×3 po or 0.25 mg/kg/d×3 sc stimulated the production of the 250 kDa protein. Treatment with higher doses (10 mg/kg/d×3 po, or 1.25 mg/kg/d×3 sc) was less effective in inducing production of this protein. Also anordiol partially inhibited the stimulatory action of E2; whereas ICI 182,780, a pure antiestrogen, at a dose of 0.3 mg/kg/d×3 sc completely blocked the stimulatory action of E2. The 250 kDa protein was not detected in the blood obtained from E2-treated ovariectomized rats. The anti-complement C3 and anti-α2-macroglobulin antibodies did not react with the ULF 250 kDa protein. The present results show that the production of the ULF 250 kDa protein is regulated by estradiol and is not a component of blood plasma. It is proposed that the estrogen-responsive 250 kDa protein may be involved in maintaining the viability of the fertilized ova and in the implantation of the blastocyst.

ISSN:0743-5800    

DOI:10.3109/07435809609030496

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

Recent studies have suggested the secretion of Atrial Natriuretic Peptide (ANP) is regulated by receptor mediated activation of protein kinase C, which causes the autocrine release of prostaglandins. Prostaglandins stimulate ANP secretion via the adenylate cyclase second messenger system. This report examined the response of right and left atrial ANP secreting cells to the three endothelin isopeptides and to cyclooxygenase inhibition. Our results show that right atrial ANP secretion is stimulated by endothelin 1 and 2 but not 3. In addition, right atrial ANP secretion is reduced by inhibition of cyclooxygenase. In contrast, left atrial ANP secretion is stimulated by endothelin 2 and 3 but not 1. Inhibition of cyclooxygenase did not affect left atrial ANP secretion. These results show the regulation of ANP secretion is different between the two atrial chambers. Right atrial cells appear to contain the prostaglandinmediated response to protein-kinase C activation, whereas left atrial cells regulate ANP secretion differently.

ISSN:0743-5800    

DOI:10.3109/07435809609030497

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

The role of androgen receptors in androgen-induced changes in rat adrenocortical and liver cytochrome c oxidase (COX) has been investigated. The anti-androgen, flutamide, blunted the increase in COX activity and COX subunits II/III and IV, that is seen with androgen treatment. Testicular feminized (Tfm) rats had levels of COX activity and COX subunits II/II and IV in adrenal cortex and liver that were intermediate between the high levels found in normal male rats and the lower levels of normal female rats. These data suggest that androgen effects on adrenal and liver COX are mediated through interactions with androgen receptors known to be present in these tissues. However, the observed changes in COX activity and COX subunits were not accompanied by altered levels of mRNAs encoding for COX II or COX IV.

ISSN:0743-5800    

DOI:10.3109/07435809609030498

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor

摘要:

2[125I]Iodomelatonin binding sites were identified in the mucosa of the human colon from Chinese patients with carcinoma of the rectum or colon using biochemical receptor assay and autoradiography. Melatonin in the colonic mucosa/submucosa and muscle layers were quantitated by radioimmunoassay. The binding of 2[125I]iodomelatonin to the membrane preparations of the human colonic mucosa/submucosa was stable, saturable, reversible and of high affinity. Rosenthal analysis from saturation studies performed at 21°C yielded an equilibrium dissociation constant (Kd) of 61.7±4.48 pmol/L (n=3) and maximum number of binding sites (Bmax) of 1.65±0.51 fmol/mg protein (n=3). The linearity of the Rosenthal plots and unity of the Hill coefficient suggested that 2[125I]iodomelatonin was bound to a single class of binding sites. The radioligand binding was displaced by 2-iodomelatonin (Ki=0.02 nmol/L), melatonin (0.65 nmol/L), 6-chloromelatonin (Ki=5.33 nmol/L), 6-hydroxymelatonin (Ki=33.8 nmol/L) and N-acetylserotonin (Ki=122 nmol/L). The characteristics of the binding sites were similar to those reported in the jejunum of duck, chicken and human but of higher affinity than those in the mouse colon. Autoradiography localizes the binding to the mucosa of the human colon. Radioimmunoassay revealed a melatonin concentration of 467±99 pg/g wet tissue of human colon (n=6). Our findings suggest that melatonin may influence the human colonic functions through interaction with its receptors in the mucosa.

ISSN:0743-5800    

DOI:10.3109/07435809609030499

出版商:Taylor&Francis    

年代:1996

数据来源: Taylor