Low-density cDNA array-coupled to PCR differential display identifies new estrogen-responsive genes during the postnatal differentiation of the rat hypothalamus.

To identify estrogen (E)-responsive genes that may play important roles in the sexual differentiation and maturation of the neuroendocrine hypothalamus, we used mRNA differential display PCR to analyze hypothalamic RNA derived from estrogen-sterilized rats (ESRs). Neonatal rats were s.c.-injected with 100 microg of 17 beta-estradiol-benzoate (EB) for 5 days. Approximately 300 out of more than 2000 RNAs examined displayed a differential expression pattern between hypothalami of the ESR females compared to their 60-day-old controls. EB-dependent expression of these genes was further analyzed by low-density cDNA array using cDNA probe sets reverse-transcribed from the same groups; 98 genes were confirmed to be differentially expressed. We selected 41 clones that showed higher density differences between the two probe sets than mean density difference in control cyclophilin cDNA blots in the cDNA array. After being cloned into pGEM-T vectors, their sequences were analyzed. Homology searches identified four genes as a protein kinase C (PKC)-binding protein, NELL2 (clone 6-1), a thyroid nuclear factor, TTF-1 (9-1), Munc18-1 (17-6), and leuserpin-2 (18-5). The other 22 genes were similar to reported genes or cDNAs such as mouse kinesin-associated protein 3 (KAP3, 8b), mouse IgE binding lectin (15-1), normalized rat brain cDNA (5-1), rat cDNA (8-1) and rat embryonic cDNA (17-1). Fifteen clones such as clone 7-3 showed no match in the GenBank Database. Further characterization of eight clones (17-1, 7-3, 8-1, 5-1, NELL2, KAP3 homolog, IgE binding lectin homolog, and TTF-1) showed that their expression in the adult female rat hypothalamus is sensitive to neonatal treatment with EB. They showed brain-specific expression and moreover, showed an increase in their mRNA level before the initiation of puberty. Some of them showed gender differences in their different postnatal expression pattern. We speculate that further study will demonstrate that many of the E-regulated genes identified in the present study play important roles in the regulation of the sexual differentiation and E-dependent maturation of the hypothalamus.

Central administration of an antisense oligodeoxynucleotide against type I pituitary adenylate cyclase-activating polypeptide receptor suppresses synthetic activities of LHRH-LH axis during the pubertal process.

Central administration of an antisense oligodeoxynucleotide against type I pituitary adenylate cyclase-activating polypeptide receptor suppresses synthetic activities of LHRH-LH axis during the pubertal process In the present study, we determined the expression of pituitary adenylate cyclase-activating polypeptide (PACAP) and PACAP receptor type I (PAC1) genes during juvenile development and the pubertal process. Female rats were assigned--based on uterine weights, the presence and abundance of uterine fluid, and their vaginal patency--to one of the following: anestrus (AE), early proestrus (EP), late proestrus (LP) or first estrus (E). The hypothalami from 22-, 24- and 26-day-old animals and from those in the peripubertal phases of AE, EP, LP and E were collected, and the content of PACAP and PAC1 mRNA was assessed. These levels were found to decrease in EP and LP. To determine the effect of PACAP on prepubertal luteinizing hormone-releasing hormone (LHRH) and LH synthesis through PAC1, a PAC1 antisense oligodeoxynucleotide (ODN) was i.c.v.-administered, and mRNA levels of LHRH, LH beta, and LHRH receptor (LHRH-R) were determined. Prepubertal increases in LHRH, LH beta, and LHRH-R mRNA levels were markedly suppressed, and the onset of puberty was delayed by the i.c.v. injection of the antisense PAC1 ODN. These data suggest that PACAP may play a role in the regulation of hypothalamic LHRH neurons, through which it regulates synthetic machinery of pituitary LH, during the pubertal process.

Progesterone increases mRNA levels of pituitary adenylate cyclase-activating polypeptide (PACAP) and type I PACAP receptor (PAC(1)) in the rat hypothalamus.

Pituitary adenylate cyclase-activating polypeptide (PACAP) regulates pituitary hormone biosynthesis and secretion through its cognate receptors. PACAP also plays an important role in the regulation of ovarian steroid biosynthesis. If so, there might be a feedback regulation of hypothalamic PACAP synthesis by the pituitary and by ovarian steroids. In the present study, we used RNase protection assays to determine changes in mRNA levels of PACAP and type I PACAP receptor (PAC(1)) under the conditions of ovariectomy and replacement with ovarian steroids. Progesterone (P) alone or in combination with estradiol (E) induced significant increases in PACAP mRNA level in the medial basal hypothalamus (MBH) and PAC(1) mRNA levels in MBH and the preoptic area (POA). This finding suggests that feedback regulation takes place between the ovary and hypothalamic PACAP neurons. P is known to be a major regulatory feedback factor for hypothalamic luteinizing hormone-releasing hormone (LHRH) neurons, but P receptor is not present in these neurons. Therefore, we examined a possible involvement of PACAP in the feedback regulatory pathway of P to LHRH neurons. After an antisense PAC(1) oligodeoxynucleotide (ODN) was i.c.v.-injected into the third ventricle of E and P-treated rats, LHRH mRNA levels were determined. The ODN markedly decreased the P-induced increase in the LHRH mRNA level. Taken together, the present data suggest that PACAP may play a role as a mediator in the regulation of LHRH synthetic machinery by stimulatory feedback of P.

Simultaneous determination of multiple transcripts and splice variants of a primary transcript using ribonuclease protection assays.

The ribonuclease (RNase) protection assay (RPA) is an extremely sensitive technique used to determine specific mRNAs from cell and tissue extracts. The present protocol presents detailed procedures for a conventional RPA using antisense RNA probes purified with a Fullengther apparatus. The Fullengther has the advantage of being a relatively quick and safe procedure compared to more conventional methods for purification of full-length RNA probes. Using this protocol, we sought to simultaneously determine multiple mRNA species, including splice variants of the type I receptor (PAC(1)) of pituitary adenylate cyclase-activating polypeptide (PACAP), an important mediator in the regulation of luteinizing hormone-releasing hormone (LHRH) synthesis by ovarian steroids such as progesterone [7]. PAC(1) has more than eight splice variants. We have been able to discriminate the hop1 variant from other splice variants. To improve our understanding of the regulation mechanism of genes that are related to each other, such as LHRH and PACAP, it is most important to simultaneously determine genes that are involved in the same physiological areas of regulation. Using only 5 microg of total RNA sample from a single rat preoptic area, we simultaneously determined five different transcripts, including four rare mRNA species such as LHRH, PACAP, and hop1 variant and other splice variants of PAC(1), as well as the internal control of cyclophilin mRNA. This protocol provides a method for the simultaneous determination of multiple transcripts using the RPA.

Social effects and circadian rhythms in squirrel monkey pituitary-adrenal activity.

Simultaneous measures of plasma cortisol and ACTH were collected at the morning peak (AM) and evening nadir (PM) of the circadian rhythm in group-housed and individually housed squirrel monkeys (Saimiri sciureus). Pronounced AM-PM differences in cortisol were evident in both conditions, but morning measures of cortisol in monkeys housed without companions were 32% higher than baseline control values observed when the same monkeys were sampled in groups. Consistent AM-PM differences in cortisol were not associated with consistent AM-PM differences in ACTH, and for monkeys housed without companions, plasma ACTH concentrations were consistently and significantly reduced (23% lower in the morning, 42% lower in the evening). All monkeys were subsequently pretreated overnight when dexamethasone to temporarily suppress the secretion of endogenous ACTH and then challenged the following morning with a bolus injection of synthetic ACTH. Monkeys housed without companions responded to the challenge with greater, more prolonged elevations in cortisol relative to monkeys housed in groups. These observations together suggest that squirrel monkeys housed without companions hypersecrete cortisol at the morning peak of the rhythm because adrenal responsiveness to ACTH is enhanced. Low circulating ACTH levels in turn are maintained by robust glucocorticoid feedback mechanisms that inhibit the synthesis or release of pituitary ACTH.

Cytotoxic quinolines (part 1). Azolylalkyloxy quinolines and 1-azolylalkyl-4(1H)-quinolones.

A series of 4-azolylalkyloxyquinolines and 1-azolylalkyl-4(1H)-quinolones has been synthesized and evaluated for cytotoxicity against various cancer cell lines. 1-Phenyl-1,2,3-triazole and 1-methylpyrazole were found to be the most effective azoles. The length of the alkyl chain was critical, with 8 to 10 carbon atoms being optimal. Several of the compounds were found to be very cytotoxic in vitro towards various cancer cells. Compounds 9o, 10k, and 10r were evaluated in vivo, but were ineffective and exhibited acute general toxicity at higher dosages.

Cytotoxic quinolines (part 2). Azolylalkylamino and-thio quinolines.

A series of azolylalkylaminoquinolines and azolylalkylthioquinolines was synthesized and evaluated for cytotoxicity against various cancer cell lines. Structure-activity relationships previously established for azolylalkyloxyquinolines were generally found to apply for the present compounds. The azolylalkylaminoquinolines were found to be more cytotoxic than the corresponding thio compounds. Oxidation of 11a to sulfones 12 and 13 resulted in a reduction of cytotoxicity. Several of the compounds were found to be very cytotoxic in vitro towards different cancer cell lines. Compound 7d, the most cytotoxic in vitro against the P388 cell line in this series, was ineffective in vivo and exhibited significant general toxicity at higher dosages.