Blood sulfur-amino acid concentration reflects an impairment of liver transsulfuration pathway in patients with acute abdominal inflammatory processes

Whole-blood free amino acids were measured in a control group made up of eight healthy women fasted for 12 h and also in eight patients with acute pancreatitis, five patients with acute cholecystitis and seven patients with acute appendicitis. Blood was withdrawn immediately on admission to hospital and again 3 d later following a controlled peripheral parenteral nutrition diet; this is with the exception of the appendicitis group. l-Cystathionine and l-methionine concentrations were significantly higher in pancreatitis and appendicitis patients when compared with controls. In the pancreatitis and cholecystitis patients, l-serine concentration was also significantly higher when compared with controls. The l-homocysteine concentration was significantly higher only in the appendicitis group when compared with the control group. l-Cystine concentration was unchanged in all the patients studied when compared with control subjects. The l-methionine : l-cystine ratio was significantly higher and the l-glutamine : l-cystine ratio was significantly lower in all the patients when compared with controls. The blood S-amino acid pattern reflects an impairment in liver transsulfuration pathway during acute abdominal processes. This work supports the idea that the l-methionine : l-cystine and l-glutamine : l-cystine ratios can be taken as good markers to evaluate the S-amino acid metabolism and suggests the importance of using N-acetylcysteine as a required nutrient in these situations.

Changes in the expression of neurohypophyseal prolactins during the estrous cycle and after estrogen treatment

Estrogens are recognized regulators of the expression of neurohypophyseal hormones and of anterior pituitary prolactin (PRL). Here we have investigated whether the levels of PRL mRNA and of 23 and 14 kDa PRL variants present in the hypothalamo-neurohypophyseal system change during the estrous cycle or in response to estrogen treatment. The reverse transcription polymerase chain reaction (RT-PCR) was performed to examine PRL mRNA expression in isolated paraventricular (PVN) and supraoptic (SON) hypothalamic nuclei. In both nuclei PRL mRNA levels appeared higher in cycling females than in male rats, with the highest level occurring at estrus. This increase may involve estrogen action, since estrogen administration to ovariectomized rats was associated with apparently higher PRL mRNA levels in both the PVN and SON. Expression of the PRL gene at these sites may occur via both transcriptional factor Pit-1-dependent and -independent mechanisms. RT-PCR detected the mRNA for Pit-1 in the PVN but only at estrus. The concentration of the 23 kDa immunoreactive PRL determined in the neurohypophysis was significantly higher during estrus and after estrogen treatment. However, no difference was detected in the levels of the neurohypophyseal 14 kDa PRL-like fragment along the estrous cycle nor after estrogen administration. This lack of parallelism between neurohypophyseal PRLs could relate to an estrogen-induced inhibition of the proteolysis of 23 kDa PRL at this site, since estrogen treatment reduced the activity of neurohypophyseal proteolytic enzymes able to cleave PRL. Altogether our results are consistent with estrogens having a stimulatory effect on PRL gene expression in the hypothalamo-neurohypophyseal system and a concomitant inhibitory action on PRL proteolysis at this site.

Expression of prolactin mRNA and of prolactin-like proteins in endothelial cells: evidence for autocrine effects

Formation of new capillary blood vessels, termed angiogenesis, is essential for the growth and development of tissues and underlies a variety of diseases including tumor growth. Members of the prolactin hormonal family bind to endothelial cell receptors and have direct effects on cell proliferation, migration and tube formation. Because many angiogenic and antiangiogenic factors are produced by endothelial cells, we investigated whether endothelial cells expressed the prolactin gene. Here we show that bovine brain capillary endothelial cells (BBCEC) in culture express the full-length prolactin messenger RNA, in addition to a novel prolactin transcript, lacking the third exon of the gene. In addition cultures of BBCEC synthesize and secrete prolactin-like immunoreactive proteins with apparent molecular masses of 23, 21 and 14 kDa. The prolactin-like nature of these proteins in supported by the observation that Nb2-cells, a prolactin-responsive cell line, were stimulated to proliferate when co-cultured with endothelial cells and this stimulation was neutralized with prolactin-directed antibodies. Finally, consistent with a possible autocrine effect of endothelial-derived prolactins, polyclonal and monoclonal prolactin antibodies specifically inhibited basal and basis fibroblast growth-factor-stimulated growth of endothelial cells. Taken together, the present findings support the hypothesis of the prolactin gene being expressed in endothelial cells as proteins that could act in an autocrine fashion to regulate cell proliferation.

Plasticity of autonomic nerves: differential effects of long-term guanethidine sympathectomy on the sensory innervation of the rat uterus during maturation

The sensory nerves, containing substance P and calcitonin gene-related peptide, and noradrenaline-containing sympathetic nerves of the rat uterus were analyzed following long-term sympathectomy with guanethidine in prepubertal (four weeks), young adult (eight weeks) and fully adult animals (18 weeks). Immunohistochemical and histochemical methods were used in association with nerve density measurements and biochemical assays. The main findings were as follows: (1) long-term guanethidine treatment completely abolished the noradrenergic innervation of the uterine horn and parametrial tissue and markedly reduced the tissue levels of noradrenaline in both regions at the three ages analysed; (2) in the uterine horn guanethidine treatment had no effect on the tissue levels of either calcitonin gene-related peptide or substance P or on the density of calcitonin gene-related peptide-containing nerves, at any of the three ages studied; (3) in the parametrial tissue increased levels of calcitonin gene-related peptide were observed at 8 and 18 weeks of age, together with a significant increase in the density of calcitonin gene-related peptide-containing nerves. Substance P levels showed a transient increase in this tissue at eight weeks. In conclusion, long-term sympathectomy with guanethidine resulted in an increase in calcitonin gene-related peptide and substance P in sensory nerves in the parametrial tissue, but not in the uterine horn. The changes in the parametrial tissue only occurred after puberty. It is suggested that sensory nerves in the uterine horn may be less responsive to sympathetic denervation since loss of sympathetic nerves occurs as part of a normal physiological process during pregnancy in this region.

Postnatal development of noradrenaline-containing nerves of the rat uterus

The postnatal development of noradrenaline (NA)-containing nerves of the rat uterus and its associated blood vessels was investigated using histochemical and biochemical methods. These studies were carried out in conjunction with examination of the morphology of the uterus and the density of blood vessels at the prepubertal, peripubertal and adult stages. It was demonstrated that: (1) the rat uterus is innervated at birth; (2) the innervation of blood vessels develops earlier than that of the myometrium and the density of NA-containing perivascular nerves is not affected by puberty; (3) between birth and day 30 (prepubertal) there was a progressive increase in the innervation of the myometrium which was accompanied by a progressive increase in the total NA content of the organ; (4) at the first oestrus there was a marked increase in the weight of the uterus and isolated myometrial and parametrial tissue. Both muscle cell size and number were also increased. The density of myometrial innervation by NA-containing nerves was markedly reduced, although the total NA content did not change at this stage. This indicates a 'dilution' of myometrial NA-containing nerves in a greater amount of non-neuronal tissue; and (5) between the peripubertal and adult stages there was a further increase in uterine weight together with an increase in the number of smooth muscle cells and a reduction in the density of myometrial NA-containing nerves. Although the density of perivascular nerves was unaffected by puberty, the number of blood vessels supplying the uterus increased during the transition to the adult stage. This was reflected by a significant increase in the total NA content of the uterine horn and of isolated myometrial and parametrial preparations.