Precocious puberty in rats induced by hypothalamic lesions: A comparison of platinum and stainless steel electrodes

Summary Precocious sexual maturation was induced in immature female rats by 2 types of unilateral hypothalamic lesions. Stainless steel electrodes produced smaller tissue defects but proved more efficient than platinum electrodes.Supported by Swiss National Science Foundation grant No. 3.016.73.Supported by Canadian Medical Research Council grant No. MT 4192.Supported by a contribution from the Roche Research Foundation for Scientific Exchange and Biomedical Collaboration with Switzerland     

Effects of sera and liver extracts from partially hepatectomized rats on liver slice DNA synthesis

Summary Sera from partially hepatectomized rats (PH) compared to sera from control rats (C) enhance liver slice DNA synthesis but depress kidney slice DNA synthesis. Alone, liver extracts from PH do not affect DNA synthesis; but adding sera to PH extracts stimulates, suggesting that sera and liver factors from PH may participate in compensatory growth.Acknowlegments. Supported by NIH, grant AM 15458, a grant from the Washington Heart Association, and Public Health Service, grant RR 5360 (Medical). The authors wish to express their appreciation to Angelina Vasques for technical assistance and Betty Mendelson, Patti Werr and Susan Dreux for secretarial help.     

Fluid and protein clearance in the rat endometrium. Part I: Ultrastructural proof of the absence of an intrinsic lymphatic system from the rat endometrium

Summary An integrated histological and ultrastructural study of the endometrial microcirculation in rats reveals that lymphatic capillaries are absent from the superficial uterine mucosa. Blood capillaries are fenestrated, and their basement membrane may be poorly developed.Supported by a grant from the Nationaal Fonds voor Wetenschappelijk Onderzoek-Fonds voor Geneeskundig Wetenschappelijk Onderzoek (Belgium).     

Increased blood pressure in the SHR is not related to a deficit in renomedullary PGE2

Summary Synthesis of prostaglandin E₂ by renal medulla from SHR and WKY rats was compared during early postnatal development. Although arterial blood pressure was significantly higher in SHR as early as 6 weeks of age, no difference in renal medullary prostaglandin synthesis was observed.Supported in part by a grant from the michigan Heart Association and NIH grant AM-10913.     

Reduction in dietary vitamin E prevents onset of hypertension in developing spontaneously hypertensive rats

Summary Reduction in dietary vitamin E intake in developing spontaneously hypertensive rats abolished the onset of hypertension which is normally evident by 3 months of age.Supported by a grant No. 4-6 to C.P.-A. from the Canadian Ontario Heart Foundation.     

Thymectomy modifies androgenizing effects of a testis transplant during critical period for neuroprogramming

Summary Thymectomy simultaneous with transplantation of a syngeneic testis from a littermate to Fischer 344 rats ameliorated the androgenizing effects of the testis transplant on ovarian morphology at 90 days of age.Supported by a Morseman Fellowship, NIH grants HD07097, AM21137 and NSF-RIAS grant SER77-06922.     

Increased cardiac noradrenaline turnover in the rat after acute exposure to environmental heat

Summary In male rats, the cardiac turnover of noradrenaline is significantly increased on acute exposure to an environmental temperature of 32°C, when compared to control experiments performed at 23°C.Supported by a grant from the Deutsche Forschungsgemeinschaft.     

Comparison of diurnal and nocturnal rates of 5-hydroxytryptamine turnover in the rat mediobasal hypothalamus

Summary Rates of 5-hydroxytryptamine (5-HT) turnover in the mediobasal hypothalamus of male rats were estimated using pharmacological methods during the daytime and at night. Concentrations of 5-HT in this hypothalamic area were higher nocturnally than diurnally; this was apparently due to increased 5-HT synthesis and decreased 5-HT catabolism at night.Supported by NIH grant RR07187 (TSK) and NIH grant HD10202 (Neuroendocrine Core).     

Phosphate mobilization from striated muscle following parathyroid hormone administration to thyroparathyroidectomized rats

Summary Parathyroid hormone administration to thyroparathyroidectomized rats resulted in a significant reduction in inorganic phosphate content of a variety of striated muscles. Most other organs were unaffected. Much of the extra urinary phosphate present after parathyroid hormone stimulation may be released from the muscles.Supported in part by a grant from the Marquette University Committee on Research.     

Increased liver calcium after calcium or milk gavage in rats

Summary For 1 or 2 h following a gavage of milk or 300 mM CaCl₂ (2 ml/100 g b.wt), rats had an increased liver calcium content when compared to rats receiving a deionized water gavage.Supported in part by a grant from the National Science Foundation (PCM 75-23603). We are grateful to Mr John O'Brien for his technical assistance.     

Influence of the pineal gland on the reproductive system of the male house mouse

Summary Procedures designed to express pineal-mediated antigonadotropic activity were performed upon male house mice. Neither blinding nor blinding plus olfactory bulbectomy of house mice resulted in testicular involution within 12 weeks. The pineal gland appears to be of little significance to reproduction in the house mouse.Supported by NICHHD grant No. HDO 7119-092.Supported by NICHHD grant No. 5P5 OHDO 8338.Supported by NSF grant No. SPI 7922 372.     

Sequential changes in serum glucose,triglycerides and cholesterol in aging of normal and alloxan-diabetic rats

Summary 16-week-old Wistar, alloxan diabetic rats exhibited progressive elevations in levels of serum glucose, total triglycerides, cholesterol and creatinine over a period of 8 weeks; hyperglycemia preceeded hyperlipidemia and hypercreatininemia and hypertriglyceridemia preceeded hypercholesteremia. Age-matched control rats failed to develop any signs of hyperglycemia or hypercreatininemia, but did develop both hypercholesterolemia and hypertriglyceridemia at 24 weeks of age. This suggests that the progressive cardiovascular derangements (e.g., atherosclerosis, hypertension) noted in experimental diabetes mellitus and in the normal aging (and maturation) process may be brought about by distinctly different biochemical processes.Supported by NIH grant nos. HL-18002 and HL-18015 and NIDA grant No. DA-02339.     

Peroxidase and gamma-glutamyl transpeptidase activities duringEimeria nieschulzi (Apicomplexa) and/orNippostrongylus brasiliensis (Nematoda) infections in the rat

Summary Results suggest that malabsorption of amino acids which occurs duringEimeria nieschulzi andNippostrongylus brasiliensis infections in rats is not due to impairment by intestinal inflammation of gamma-glutamyl transpeptidase activity.Supported by NIH MBRS grant RR08012-13.     

A new technique of pinealectomy for adult rats

Summary A new technique of pinealectomy for rats is described which brings the pineal into view of the experimenter facilitating its removal and also allows for completely parallel sham operations.Acknowledgments. We thank Drs J. A. Mitchell, R. R. Gala and A. Weinsieder for their cooperation in the initial phases of this work and Hedwig A. Murphy for her help with the illustrations. Supported by USPHS, grant No. RR 05384, and the Department of Anatomy.     

The effect of methaqualone on prenatal development in the rat

Summary Methaqualone treatment of pregnant rats in doses of 100–200 mg/kg day produces resorption and a series of anomalies whose incidence increases with the dose-level employed.Acknowledgment. Supported by the National Research Council of Canada, grant No. A0292. Methaqualone was generously supplied by W. H. Rorer, Canada, Ltd.     

Antagonism of amphetamine stereotyped behavior by diastereoisomeric dihydrodibenzothiepin neuroleptics

Summary Differences in neuroleptic activity were observed between the diastereoisomers of a dihydrodibenzothiepin derivative, while no potency differences were seen between their respective enantiomorphs.Supported by USPHS grant NS-10203.     

Renal injury after muscle extract infusion in rats: Absence of toxicity with myoglobin

Summary A crude muscle extract infused into rats produced oliguria, a precipitous drop in total hemolytic complement, and in circulating white cell and platelets counts. A mild vaso-depressor effects was noted. These changes were not produced by myoglobin or saline infusion. Muscle constituents other than myoglobin are responsible for the systemic and renal nephrotoxic effects observed.Supported by Medical Research Council of Canada grant MA-1579.     

Renal ammoniagenesis in kidney slices from rats undergoing glycerol-induced acute tubular necrosis

Summary Compared to control, kidney slices from rats undergoing glycerol-induced ATN produce less ammonia from glutamate, but show no difference when glutamine is substrate. However, gluconeogenesis from glutamine, like glutamate, is decreased in acute tubular necrosis (ATN). We conclude that renal ammoniagenesis is influenced by ATN. Glycerol-induced ATN causes a relative increase in glutamine deamidation and a decrease in glutamate deamination.Supported by a grant from the American Kidney Fund.     

Diurnal rhythm of ethanol metabolism in the rat

Summary Male Sprague-Dawley rats injected with 2.0 g/kg of ethanol and analyzed 1 h later at 8 specific times of the day showed diurnal rhythms for alcohol concentrations in the blood, urine, brain and liver tissues. The circadian fluctuation noted for the concentrations of blood and tissue ethanol might indicate a diurnal variation in the enzymatic metabolism of ethanol.Supported by a grant from the US National Aeronautics and Space Administration.     

Acid excretion in young and adult Wistar Kyoto and spontaneously hypertensive rats

Summary Wistar Kyoto rats (WKy), the most widely accepted control for SH rats, show an inability to excrete acid appropriately when compared to another normotensive strain, SD. Coupled with the fact that KWy also develops sodium-sensitive hypertension, this makes them a more complex control than realized. At very young ages (<10-week-old), neither SH nor WKy show any deficiency in acid excretion.Acknowledgments. Supported by AHA grant 76 1019 and NIH grant AM 15458. The excellent secretarial help of Susan Dreux and Betty Mendelson is acknowledged.