Antisense mRNA for NPY-Y1 receptor in the medial preoptic area increases prolactin secretion

We investigated the participation of neuropeptide Y-Y1 receptors within the medial preoptic area in luteinizing hormone, follicle-stimulating hormone and prolactin release. Four bilateral microinjections of sense (control) or antisense 18-base oligonucleotides of messenger ribonucleic acid (mRNA) (250 ng) corresponding to the NH2-terminus of the neuropeptide Y1 receptor were performed at 12-h intervals for two days into the medial preoptic area of ovariectomized Wistar rats (N = 16), weighing 180 to 200 g, treated with estrogen (50 µg) and progesterone (25 mg) two days before the experiments between 8.00 and 10:00 a.m. Blockade of Y1 receptor synthesis in the medial preoptic area by the antisense mRNA did not change plasma luteinizing hormone or follicle-stimulating hormone but did increase prolactin from 19.6 + or - 5.9 ng/ml in the sense group to 52.9 + or - 9.6 ng/ml in the antisense group. The plasma hormones were measured by radioimmunoassay and the values are reported as mean + or - SEM. These data suggest that endogenous neuropeptide Y in the medial preoptic area has an inhibitory action on prolactin secretion through Y1 receptors

Effect of high ingestion of dehydrated pumklin (Cucurbita pepo L. ) on the cholesterol metabolism and on the hepatic histology in mice

The hypercholesterolemia is one of the most relevant risk factors in atherosclerosis, the latter being responsible for a high mortality in most Western countries. A high intake of foods from plant origin is one of the recommendations for the control of hypercholesterolemia, probably because of their fiber content. This study was designed to evaluate the effects of the ingestion a pumpkin-based diet on cholesterol levels. Fifty mices were divided in three groups: I, animals fed on normocholesterolemic control diet: II, animals fed on a hypercholesterolemic diet; III, animals fed on a hypercholesterolemic diet containing dehydrated pumpkin during 8 weeks. The results showed that dehydrated pumpkin, when administered in high concentration in the diet, reduced the levels of plasmatic and hepatic cholesterol but may caue relevant lesions in liver. Further studies are necessary to evaluate the right proportion of pumpkin to reduce the cholesterolemia without undesirable effects. This study reinforces the need for the continuous support of an experienced histopathologist to detect eventual damage that are not evident on macroscopic examination in all nutritional studies involving tests with diets