The effects were observed of moving male, adult Han:Sprague rats in their cages or of exposure to ether for 1 min on the plasma concentration profiles of 25 blood characteristics linked with stress and shock reactions. 5 min after the stress serum prolactin, corticosterone, thyroid-stimulating hormone, follicle-stimulating hormone, luteinizing hormone, triiodothyronine and thyroxin levels were elevated 150-500% compared with those in blood collected within 100 s of entering the animal room. Heart rate (telemetrically recorded), packed cell volume,, haemoglobin and plasma protein content were 10-20% elevated 2-10 min after cage movement or 2-20 min after ether confrontation over those of controls sampled within 50 s, indicating circulatory and microcirculatory shock reactions. Serum glucose, pyruvate and lactate concentrations rose by 20-100% 1-5 min after cage movement and 1-15 min after ether exposure. Phosphate, calcium, urea, apartate and alanine transferases, alkaline phosphalase and leucine arylamidase were not altered significantly by either stressor, while potassium and bound glycerol fell for 1 min and 5-20 min respectively. The presence of a familiar animal attendant working in the room without touching the cages did not markedly affect the blood characteristics being studied.

Spontaneous locomotor activity (LA) was recorded in five inbred strains of laboratory rats (ACI/ZtmKEY WORDS: circadian and ultradian rhythms; strain differences; locomotor activity; laboratory rat.

The glomerular distribution in the renal cortex of the Munich Wistar Frömter (MWF) rat, a substrain of the Munich Wistar rat selected for superficial glomeruli, was compared to that of a control strain (LEW/Ztm) between 10 and 150 days of age. While there were no significant differences in body growth, kidney weight, or growth of the renal cortex in these two strains, the average diameter of Bowman’s capsule and of the glomerular tuft was significantly larger (about 12%) in rats of the MWF strain which were older than 60 days. In histological sections of kidneys of MWF rats in all age groups, many glomeruli in direct contact with the renal capsule were found; thus, this developmental step must have taken place before 10 days of age. The appearance of superficial glomeruli was due to a shift of glomeruli to a position just under the renal surface, the subcapsular zone or ‘cortex corticis’, which is normally free of glomeruli. For the rest of the renal cortex there were only slight differences in glomerular density and in total number of glomeruli per section between these two strains. These results lead us to suppose that superficial glomeruli belong to a special nephron type; thus, these glomeruli are not enveloped by parts of the proximal tubule.

SummaryThe mouse inbred strain HLG has only recently been submitted for international registration. It has been widely used in radiological studies. Since these mice tend to become obese, they may be of interest for studies concerning fat metabolism. Therefore, the present ageing study examines the sex-specific development of body weight, body composition, adipocyte size as well as the organ weight of liver, heart and thigh muscles of the inbred strain HLG (54 males/53 virgin females) between day 40 and 360 of life.The body weight development showed a distinct sexual dimorphism, quickly increasing in the case of males but comparatively protracted in females until maturity. Significantly higher values for body and fat-free dry weight as well as body water were found in males of all ages. Body fat and adipocyte diameter were only higher in the 80 and 120 day-old males. Thus, the increase in female body weight resulted largely through a rise in body fat as additionally evidenced by the sex-specific correlation of characteristics. A 2-fold analysis of variance showed sex differences in the relative weights of liver and muscle, but not of the heart. A sex-specific close correlation was observed between body and liver weights in males until day 180. Correlations between body fat and other characteristics were only rarely found. Differences in coefficients of variation largely depended on the characteristics. A higher variability was also found for some characteristics in the youngest groups (40 days). A sex-specific difference was only seen in the case of body fat content for 60 day-old mice (female>male).