Preliminary evidence that a dopamine receptor antagonist blocks the prolactin-inhibitory effects of melatonin in anosmic male rats

Summary Previous studies have shown that daily afternoon injections of melatonin in anosmic male rats result in depressed accessory sex organ weights and serum prolactin levels. The present data indicate that the prolactin-inhibitory effect of melatonin may be mediated via the dopaminergic system.This work was supported by NIH Biomedical Research Support Grant No. 3150-80.     

Regulation of male sex determination: genital ridge formation and Sry activation in mice

Sex determination is essential for the sexual reproduction to generate the next generation by the formation of functional male or female gametes. In mammals, primary sex determination is commenced by the presence or absence of the Y chromosome, which controls the fate of the gonadal primordium. The somatic precursor of gonads, the genital ridge is formed at the mid-gestation stage and gives rise to one of two organs, a testis or an ovary. The fate of the genital ridge, which is governed by the differentiation of somatic cells into Sertoli cells in the testes or granulosa cells in the ovaries, further determines the sex of an individual and their germ cells. Mutation studies in human patients with disorders of sex development and mouse models have revealed factors that are involved in mammalian sex determination. In most of mammals, a single genetic trigger, the Y-linked gene Sry (sex determination region on Y chromosome), regulates testicular differentiation. Despite identification of Sry in 1990, precise mechanisms underlying the sex determination of bipotential genital ridges are still largely unknown. Here, we review the recent progress that has provided new insights into the mechanisms underlying genital ridge formation as well as the regulation of Sry expression and its functions in male sex determination of mice.     

Acetyl-L-carnitine treatment stimulates oxygen consumption and biosynthetic function in perfused liver of young and old rats

The effect of treatment with acetyl-L-carnitine on hepatic mitochondrial respiration and biosynthetic function in perfused liver from young (90 days) and old (22-24 months) rats was studied. Rats were given a 1.5% (w/v) solution of acetyl-L-carnitine in their drinking water for 1 month and oxygen consumption together with the rate of gluconeogenesis, urea synthesis, and ketogenesis with and without added substrates were measured in perfused liver. Mitochondrial oxygen consumption was also assessed in liver homogenate and isolated mitochondria to determine the maximal capacity for oxidative phosphorylation. Acetyl-L-carnitine treatment almost completely restored the age-dependent decline in oxygen consumption, gluconeogenesis, urea synthesis, and ketogenesis found in perfused liver of old rats to the levels found in young rats. In addition, acetyl-L-carnitine treatment increased oxygen consumption and biosynthetic function in perfused liver from young rats. After acetyl-L-carnitine treatment, we found detectable 3-oxoacyl-CoA-transferase activity associated with a consumption of ketone bodies in young and old rats. Finally, oxygen consumption measured in homogenate and isolated mitochondria did not change with age and acetyl-L-carnitine treatment. Our results show that in perfused liver, acetyl-L-carnitine treatment slows the age-associated decline in mitochondrial respiration and biosynthetic function. In addition, treatment of young rats with acetyl-L-carnitine has a stimulating effect on liver metabolism, probably through an increase in ATP production. Received 25 October 2000; received after revision 14 December 2000; accepted 11 January 2001     

Einfluss des Licht-Dunkel-Wechsels auf den O2-Umsatz der Rattenleber

Summary Similar diurnal periodicity in oxygen consumption of liver slices in Wistar rats was observed as that previously found in Sprague-Dawley rats. The rate of oxygen consumption was low in the morning and high in the evening. After inversion of lighting regimes, the phase shifted and reached the reversal curve in about 30 days. On the basis of these findings, it is estimated that diurnal periodicity in oxygen consumption of liver slices is influenced by alteration of the periods of light and darkness. Liver glycogen rhythm showed a reversed correlation to that of oxygen consumption in both lighting regimes.     

Biochemical and immunochemical evidence for the origin of the spermatophore material inGlossina morsitans morsitans Westwood

Summary Protein patterns in secretions from fully differentiated male accessory reproductive glands (ARG), spermatophore (Sp) and testes (Te) of the tsetse,Glossina morsitans morsitans Westwood, were determined by isoelectrofocusing. Isoelectrofocusing patterns of total ARG proteins and those of Sp were remarkably similar. At least 27 bands were detected in ARG and Sp. Out of these, 13 were major protein bands and isoelectrofocused in the pl range of 4 and 6.55. About 10 of these 13 were found to be acidic. Ouchterlony immunodiffusion and straight line immunoelectrophoresis showed that male accessory reproductive gland secretory proteins and spermatophore share common immunological characteristics which are different from those of the testes.     

Effect of glucocorticoids injected into pregnant female mice and rats on weight of male sexual glands in adult offspring and testosterone level in fetus in genotype-dependent

Injection of corticosterone into CBA/Lac, C57BL/6J and BALB/c mice, or hydrocortisone into aggressive and domesticated rats, on days 16 and 18 of pregnancy decreased the weight of sexual glands in adult male offspring of the C57BL/6J and domesticated mothers but increased these values in male offspring of the CBA/Lac and aggressive mothers. When injected into pregnant aggressive and domesticated rats, corticosterone affected testosterone levels in 21-day-old male fetuses. The changes were also genotype-dependent and followed the course of changes in the weight of the accessory sex glands in adults. It is suggested that glucocorticoids given during the prenatal period can effect plasma testosterone levels of male fetuses and the development of the sexual glands in a genotype-dependent manner.     

Cutaneous respiration in a Selachian (Scyliorhinus caniculus L.)]

Cutaneous oxygen consumption (Mo2) and cutaneous oxygen uptake from the external medium were investigated in an elasmobranch Scyliorhinus caniculus L. In spite of an important Mo2 (2.75 +/- 0.28 nmol.mn-1 cm-2 ; n=6) a positive net flux of oxygen through the skin takes place (2.98 +/- 0.33 nmol. mn-1 .cm-2). The skin of the dogfish in an exchanger for oxygen supplying 10% of oxygen requirements of other organs of the body in these experimental conditions (t = 13 degrees C).     

Über die Entwicklung des Fremdkörpergranuloms in verschiedenen Organsystemen

Summary The weight has been measured of the granuloma produced after implantation of the same foreign body in the kidneys, the testes, the liver and the subcutaneous tissue of male rats. It was found that granulomae in the testes and liver are nearly twice as heavy as in the kidney or in the subcutaneous tissue. Enhancement or inhibition of this reaction by treating the animals with cortexone shows organ-dependent effects on granuloma formation.     

The effect of ascorbic acid on cadmium accumulation in guinea pig tissues

Accumulation of cadmium in organs of guinea pigs after subchronic oral cadmium treatment (1 mg Cd/animal/24 h) was in the following order: kidneys > liver > heart > testes > brain. The preventive effects of high doses of ascorbic acid (AA) against cadmium deposition were more pronounced in the testes, heart and brain, and in the kidney only after short-term cadmium treatment. Ascorbic acid had no protective effect on cadmium accumulation in the liver.     

The effect of ascorbic acid on cadmium accumulation in guinea pig tissues.

Accumulation of cadmium in organs of guinea pigs after subchronic oral cadmium treatment (1 mg Cd/animal/24 h) was in the following order: kidneys > liver > heart > testes > brain. The preventive effects of high doses of ascorbic acid (AA) against cadmium deposition were more pronounced in the testes, heart and brain, and in the kidney only after short-term cadmium treatment. Ascorbic acid had no protective effect on cadmium accumulation in the liver.     

Influence of light on the plasma gonadotropin concentrations in the newborn rat.

The physiological increase in plasma gonadotropin (LH and FSH) levels in newborn rats is indisputably influenced by light. Permanent illumination accentuates this increase, whereas darkness decreases it in 16-day-old female rats. In male rats of the same age, only permanent illumination was tested with the same results.     

Effect of rabbit antiserum to ovine LH on reproductive organs in male hamsters and guinea-pigs

Summary Administration of rabbit antiserum to ovine luteinizing hormone to immature hamsters and guinea-pigs resulted in a significant decrease in the weights of testes, seminal vesicle and ventral prostate.The author wishes to thank Prof. N.R. Moudgal for his interest and Family Planning Foundation for financial assistance.     

Oxygen consumption of hibernating worker ants Dolichoderus quadripunctatus as a function of temperature and level of population]

The oxygen consumption of "hibernating" ants shows a grouping effect translated by a significant decrease in the level of oxygen consumption as a function of grouping effect. The general relation between oxygen consumption and the living body mass is the same, if the living material belongs to a single animal, or a social community of ants.     

Abnormalities in the development and reproduction of Blattella germanica (L.) (Dictyoptera: Blattellidae) treated with insect growth regulators with juvenile hormone activity

Summary Laboratory populations of German cockroach reared on food treated with R-20458 (75 ppm) or Ro 20-3600 (3000 ppm) became completely sterile and eventually extinct. The hypertrophied oocytes had excessively laid chorion, and the hypertrophied accessory sex glands contained excessive amounts of protein.     

Bilateral lesions of suprachiasmatic nucleus eliminate circadian rhythms of oxygen consumption and the respiratory quotient in rats

Bilateral lesions of the suprachiasmatic nucleus of the hypothalamus of rats abolished circadian rhythms of oxygen consumption and of the respiratory quotient (RQ). The RQ remained constant at a level intermediate between the maximum (about 1.0) and minimum (about 0.9) values in control animals.     

Bilateral lesions of suprachiasmatic nucleus eliminate circadian rhythms of oxygen consumption and the respiratory quotient in rats

Summary Bilateral lesions of the suprachiasmatic nucleus of the hypothalamus of rats abolished circadian rhythms of oxygen consumption and of the respiratory quotient (RQ). The RQ remained constant at a level intermediate between the maximum (about 1.0) and minimum (about 0.9) values in control animals.     

Estrogen and accessory sex gland lipids

Summary Administration of estradiol-17 elicited differential responses on accessory sex glands of rats. In caput epididymis, the estrogen treatment led to an accumulation of glycerides and phospholipids while in cauda epididymis, there was no significant change. However, in seminal vesicles, depletion of phospholipids was observed In prostate, the treatment, resulted in an accumulation of glycerides.Part of Ph.D. Thesis. Umapathy, E., Thesis. University of Madras, India, 1977.     

Influence of light on the plasma gonadotropin concentrations in the newborn rat

Summary The physiological increase in plasma gonadotropin (LH and FSH) levels in newborn rats is indisputably influenced by light. Permanent illumination accentuates this increase, whereas darkness decreases it in 16-day-old female rats. In male rats of the same age, only permanent illumination was tested with the same results.Acknowledgments. We would like to thank Dr C. Kordon (Unité de Neurobiologie, INSERM, rue d'Alésia, F-75014 Paris) who welcomed us in his laboratory and advised us on these experiments.     

The effects of a juvenile hormone analogue on the male reproductive organs of the red cotton bug,Dysdercus cingulatus (Heteroptera)

Summary The maleDysdercus cingulatus F., when treated with the JHa, methyl-3, 7, 11-trimethyl-7, 11-dichloro-2-dodecenoate, showed striking morphological deformities in the gonads, such as formation of additional apical growth on the testes, highly deformed, reduced vasa deferentia and accessory glands.Acknowledgments. We wish to thank Prof. P. Ramchender Rao, Head, Department of Zoology, Osmania University for facilities and encouragement. The financial assistance to P. Judson and B. Julius Divakar by the Council of Scientific and Industrial Research, New Delhi is gratefully acknowledged.     

Resuscitation of cadaveric livers from non-heart-beating donors after warm ischemic insult: a novel technique tested in the rat

Clinical liver transplantation has become the therapy of choice in end-stage liver disease, but the limited availability of suitable donor organs still impedes its widespread application. In order to increase the availability of donor organs for liver transplantation, it would be advantageous if ischemically damaged livers could be resuscitated from cadavers in which the heart has stopped beating. A method for doing this has been developed in a rat model. Compared to livers excised from rats in which the heart is still beating, severe deteriorations of tissue integrity and functional performance were evident in predamaged livers after cold preservation without supplementary treatment. A treatment of those livers which included an antioxidant rinse with superoxide dismutase, and venous vascular insufflation of gaseous oxygen during preservation, completely prevented tissue alterations upon reperfusion, and promoted a functional recovery of the livers, making them comparable to organs harvested from heart-beating donors.