Sex differences in the distribution of androgen receptors in the human hypothalamus.

The present study reports for the first time the distribution of androgen receptor immunoreactivity (AR-ir) in the human hypothalamus of ten human subjects (five men and five women) ranging in age between 20 years and 39 years using the antibody PG21. Prolonged postmortem delay (72:00 hours) or fixation time (100 days) did not influence the AR-ir. In men, intense nuclear AR-ir was found in neurons of the horizontal limb of the diagonal band of Broca, in neurons of the lateromamillary nucleus (LMN), and in the medial mamillary nucleus (MMN). An intermediate nuclear staining was found in the diagonal band of Broca, sexually dimorphic nucleus of the preoptic area, paraventricular nucleus, suprachiasmatic nucleus, ventromedial nucleus, and infundibular nucleus, whereas weaker labeling was found in the bed nucleus of the stria terminalis, medial preoptic area, dorsal and ventral zones of the periventricular nucleus, supraoptic nucleus, and nucleus basalis of Meynert. In most brain areas, women revealed less staining than men. In the LMN and the MMN, a strong sex difference was found. Cytoplasmic labeling was observed in neurons of both sexes, although women showed a higher variability in the intensity of such staining. However, no sex differences in AR-ir were observed in the bed nucleus of the stria terminalis, the nucleus basalis of Meynert, or the islands of Calleja. Species differences and similarities of the AR-ir distribution are discussed. The present results suggest the participation of androgens in the regulation of various hypothalamic processes that are sexually dimorphic.

Interrelations between hypothalamic somatostatin and proopiomelanocortin neurons.

Somatostatin receptors were visualized by [125I]-Tyr0-DTrp8-somatostatin radioautography on 35% of arcuate neurons containing proopiomelanocortin (POMC) mRNA, as identified by in situ hybridization using a [35S] labelled riboprobe on 5 microm-thick consecutive sections. Furthermore, double immunohistochemical staining revealed contacts of beta-endorphin or alpha-MSH containing fibres with a majority of somatostatin perikarya in the anterior hypothalamic periventricular nucleus. Taken together, these data indicate that hypothalamic somatostatin and POMC neurons are interconnected. The results are discussed in term of intrahypothalamic control of GH secretion.

Growth hormone-releasing hormone, somatostatin, galanin and beta-endorphin afferents to the hypothalamic periventricular nucleus.

A combined retrograde tracing (wheat germ agglutinin-horseradish peroxidase-gold complex)-immunohistochemical technique was used to identify the origin of growth hormone-releasing hormone (GHRH)-immunoreactive (ir), beta-endorphin-ir, galanin (GAL)-ir and somatostatin (SRIH)-ir terminals in the hypothalamic periventricular nucleus, which contains all the hypophysiotrophic SRIH-ir neurons. Retrogradely labeled cells were mostly observed ipsilaterally in the arcuate, dorsomedial (DMH), suprachiasmatic nuclei and the parvocellular part of the paraventricular nucleus. They were less abundant in the ventromedial and periventricular nuclei and in the lateral hypothalamus. The proportion of retrogradely labeled GHRH cells was greater at the outer rim of the ventromedial nucleus (10%) than in the arcuate nucleus proper (3%). In the arcuate nucleus, 14% of the SRIH-ir cells projected to the periventricular nucleus. Of the GAL-ir cells in the arcuate and the DMH 10% were double-labeled. Scattered retrogradely labeled GAL-ir cells were observed in paraventricular and perifornical nuclei and in the lateral hypothalamus. Of the beta-Endorphin-ir cells in the ventral part of the arcuate nucleus 15% were retrogradely labeled. It is concluded that: (1) There is no major direct connection between the hypophysiotropic GHRH and SRIH neurons, respectively, located in the arcuate and periventricular nucleus. (2) GHRH projections to the periventricular nucleus arise mainly from cells located at the outer rim of the ventromedial nucleus. (3) Intrahypothalamic SRIH projections to the periventricular nucleus arise from arcuate SRIH neurons located along the wall of the third ventricle. (4) GAL neurons from the DMH and the arcuate nucleus innervate to the same extent the periventricular nucleus. (5) beta-Endorphin arcuate neurons strongly innervate the periventricular nucleus.

Corticotropin-releasing factor induces differential behavioral and cardiovascular effects after intracerebroventricular and lateral hypothalamic/perifornical injections in rats.

The contribution of the lateral hypothalamic/perifornical (LH/PFx) area in mediating central effects of corticotropin-releasing factor (CRF) on cardiovascular and behavioral activity was assessed by monitoring blood pressure, heart rate and behavioral responses for a 45-min period after injections of various doses of CRF into the LH/PFx region or the lateral cerebral ventricle (intracerebroventricular, i.c.v.) in conscious, unrestrained rats in a familiar environment. After LH/PFx injection, CRF (3 and 30 ng) dose-dependently induced behavioral activation, predominantly consisting of grooming, eating and locomotor activity. Concomitantly, dose-related increases in mean arterial pressure (delta MAP) and heart rate (delta HR) were observed. Increases in MAP and HR following injection of 3 ng CRF were associated with the paroxysmal occurrence of behavioral activation and as such superimposed on CRF-induced elevation of baseline MAP and HR. Thirty nanograms CRF given i.c.v. produced grooming behavior similar to that observed after the same dose injected into the LH/PFx region, but failed to induce significant changes in cardiovascular concomitants. Rats receiving 100 ng CRF i.c.v., showed a significant increase in behavioral activity, respective to rats treated with 30 ng CRF in the LH/PFx, the tachycardiac responses, however, being similar in these groups. Both doses of CRF i.c.v. failed to induce significant delta MAP. The effects of CRF on cardiovascular and behavioral activity were more marked when the peptide was injected into the caudal part of the LH than those measured after administration into the rostral LH. Similarly, injections of CRF around or dorsal to the fornix (PFx) were more effective than those located ventrally to it. This site specificity of CRF-evoked responses was reflected in differential time response relations of the various effects. In summary, when i.c.v. is the route of administration, a higher dose of CRF is required to induce autonomic and behavioral responses similar to those elicited by CRF injected into the LH/PFx. The cardiovascular and behavioral effects of LH/PFx-CRF indicate that this region may be an important site for central CRF to produce stress-related autonomic and behavioral responses. In addition, the CRF-induced effects, both in magnitude and onset, show site specificity, the caudal LH and perifornical area being more responsive to the peptide than the rostral LH and the area ventral to the Fx. As CRF-evoked behavioral activation does not necessarily coincide with changes in MAP and HR, our data suggest a dissociation of the peptide's central actions to influence behavioral and autonomic responses.

Alterations in brain atrial natriuretic polypeptide levels in hypophysectomized rats.

Twelve days after hypophysectomy depleted atrial natriuretic polypeptide (ANP) concentrations were measured in the plasma and in 8 of 18 microdissected brain nuclei of rats. Reduced ANP levels were found in brain structures (subfornical organ, organum vasculosum laminae terminalis, preoptic and hypothalamic periventricular nuclei, paraventricular nucleus, lateral hypothalamic area), which are directly involved in the central regulations of salt and fluid homeostasis, as well as in the medial amygdaloid nucleus and the locus ceruleus. ANP concentrations in the median eminence, medial preoptic and arcuate nuclei did not alter by hypophysectomy. Elevated ANP concentrations were measured only in the supraoptic nucleus of hypophysectomized rats.

A phase I, II study of high-dose 5-fluorouracil and high-dose leucovorin with low-dose phosphonacetyl-L-aspartic acid in patients with advanced malignancies.

Twenty-eight patients with refractory advanced malignancies were treated with a 24-hour infusion of 5-fluorouracil (5-FU), leucovorin (LV), and N-(phosphonacetyl)-L-aspartic acid (PALA) weekly. Twenty-seven patients were evaluable to assess toxicity and antitumor activity. The PALA was administered as an intravenous bolus over 15 minutes at a fixed dose (250 mg/m2) 24 hours before the start of the 5-FU and leucovorin infusions. Initially the dose of 5-FU was 750 mg/m2; this was increased incrementally to 2600 mg/m2. The LV was administered in a fixed dose of 500 mg/m2 concurrently with the 5-FU over a 24-hour period. This regimen was repeated weekly. Diarrhea, stomatitis, nausea, and vomiting were among the dose-limiting toxicities. Others were hand-foot syndrome, hair loss of the scalp and eyelashes, overall weakness, rhinitis, and chemical conjunctivitis. The maximum tolerated dose of 5-FU in this combination and schedule was 2600 mg/m2. Seven of 14 patients treated with 2600 mg/m2 were able to tolerate the chemotherapy on a weekly basis without interruption. The other seven patients required dose reductions, but most received 5-FU at a dose of 2100 mg/m2. Twenty-three of 27 patients were treated previously. Eight patients had a partial response; five of these were treated previously. A complete response was observed in one patient with pancreatic carcinoma, previously untreated. The overall response rate for patients treated with 2100 or 2600 mg/m2 of 5-FU was nine of 18 patients (50%). Three of four previously untreated patients with pancreatic cancer responded to this treatment (two responded partially, and one had a complete response). One of three heavily pretreated patients with non-small cell lung cancer had a partial response as did a patient with breast cancer. Four of ten patients with colorectal cancer responded to the treatment (four partial responses), of whom three had been treated previously.