Olof Rugarn

Radioimmunoassay for rat galanin: immunochemical and chromatographic characterization of immunoreactivity in tissue extracts.

Galanin is a regulatory peptide with wide distribution in the central and peripheral nervous system and with numerous biological effects. Several radioimmunoassays based on antisera raised against porcine galanin have been used to measure immunoreactivity in rat tissues. However, considerable lack of parallelism has been observed between the porcine standard and rat tissue extracts, which may decrease the reliability of the quantitative data. The purpose of the present study was therefore to raise antibodies against rat galanin and establish a competitive radioimmunoassay for rat galanin. Two antisera, RatGal4 and RatGal5, were characterized in detail. The homogeneity of the immunoreactive material from several tissues was also investigated with column chromatography. At reverse-phase high-pressure liquid chromatography more than 95% of the immunoreactive material from rat CNS eluted as a single peak in the position of synthetic rat galanin, whereas almost half of the immunoreactive material from the intestine eluted in positions different from the synthetic peptide. Extracts of rat brains as well as jejunum diluted in parallel with the standard curve for both antisera. We conclude that measurements of rat galanin based on these antisera are therefore more reliable than those based on antisera raised against porcine galanin.

Sex differences in neuropeptide distribution in the rat brain

We have investigated possible sex differences in the regional concentrations of neuropeptides in the rat brain. Immunoreactive neurotensin (NT), neurokinin A (NKA), galanin (GAL), calcitonin gene-related peptide (CGRP), substance P (SP) and neuropeptide Y (NPY) were measured by radioimmunoassay in frontal cortex, occipital cortex, hippocampus, striatum, hypothalamus and pituitary in male and female pre- and postpubertal rats. Sex differences were found for NPY (p < 0.001), NT (p < 0.01) and GAL (p < 0.05), in particular in hippocampus, striatum, hypothalamus and pituitary, but not for CGRP, SP and NKA. Results from analysis of neuropeptides in one sex may not be entirely applicable to the other.

Serum concentrations of 17β-estradiol in ovariectomized rats during two times six weeks crossover treatment by daily injections in comparison with slow-release pellets

Estrogens exert widespread biological functions that reach far beyond their well‐known role in reproduction. Exogenous administration of 17β‐estradiol to ovariectomized experimental animals is of the utmost importance in elucidating its mechanisms of action. In the present study, we compared two different modes of exogenous administration of 17β‐estradiol to ovariectomized rats in relation to the serum 17β‐estradiol concentrations over prolonged periods of time. 17β‐estradiol was administered either by slow‐release pellets (Innovative Research of America, Sarasota, Fl. 34236, USA, 90‐day release, NHH‐115, 1.5 mg) or by daily subcutaneous injections of 15 µg 17β‐estradiol dissolved in sesame oil. After 6 weeks, the mode of administration of estradiol was changed to the opposite method and continued for a further 6 weeks. Blood samples for measurement of serum 17β‐estradiol were taken every second week. After 2 weeks, the serum concentrations of 17β‐estradiol in group A initially receiving the pellets were 73 % higher (p<0.001) compared to those of group B receiving daily injections. The difference was even more prominent, 580 % (p<0.001), after 4 weeks. Steady state was reached at week 6 in group A, but already by week 4 in group B. Once steady state was reached, the concentrations were the same in both groups for the remainder of the experiment (12 weeks in total). Our study indicates that steady‐state concentrations of 17β‐estradiol occur 5–6 weeks later than the 48 h the manufacturer of the slow‐release pellets claims.

Eclampsia at a tertiary hospital 1973-99

Background.  To investigate changes in incidence, patient characteristics, comorbidity and in the care provided in cases of eclampsia at a tertiary hospital during the period 1973–99.

EFFECTS OF ESTRADIOL, PROGESTERONE, AND NORETHISTERONE ON REGIONAL CONCENTRATIONS OF GALANIN IN THE RAT BRAIN

Concentrations of immunoreactive galanin were compared in eight gross brain regions of ovariectomized female rats treated with either estradiol, estradiol + progesterone, estradiol + norethisterone, or placebo. Higher concentrations with estradiol treatment compared with placebo were found in the pituitary (357%), frontal cortex (162%), occipital cortex (174%), hippocampus (170%), and median eminence (202%). A more profound difference with addition of progesterone or norethisterone was seen in the pituitary (529% and 467%, respectively). Sex steroids, particularly estradiol, modulate galanin concentrations not only in reproductive, but also in nonreproductive, brain regions.

Progesterone and norethisterone have different effects on tachykinin-like immunoreactivity in rat cortex and striatum

OBJECTIVE The purpose of this study was to investigate the effects of progesterone and the most commonly prescribed synthetic progestogen, norethisterone, on regional immune-like reactivity of neuropeptide Y (NPY), substance P (SP), neurokinin A (NKA) and neurotensin (NT) in brains of female ovariectomized estradiol-substituted rats. RESULTS Norethisterone+estradiol-treated rats had 44% lower SP levels compared with estradiol-only-treated in frontal cortex and 20% lower NKA levels in comparison with progesterone+estradiol-treated in frontal cortex. Progesterone+estradiol-treated rats had 66% lower SP levels in striatum in comparison with both estradiol-only-treated and norethisterone+estradiol-treated. No significant results were found for NPY and NT. CONCLUSION Progesterone and the synthetic progestogen, norethisterone, have different effects on SP- and NKA-like immunoreactivity in rat cortex and striatum. The effects of NET on SP- and NKA-like immunoreactivity in frontal cortex may contribute to the mood effects ascribed to this progestogen in clinical usage.

Galanin in the hippocampal formation of female rats – effects of 17β-estradiol

17Beta-estradiol induced an increase in tissue concentrations of galanin in the hippocampal formation of ovariectomized rats. This increase was dose- and time dependent, and occurred already 60 min after steroid administration and was not blocked by Tamoxifen). There was also an increase in galanin in the pro-estrous phase in regularly cycling rats. The estrogen-induced rapid increase may at least in part be due to decreased release of galanin as demonstrated by in vivo microdialysis studies. Thus, sex steroid hormones may influence signalling molecules in brain areas of importance for cognitive functions.