Plasma and tissue testosterone concentrations were determined by radioimmunoassay in 12 eight-month-old sexually mature New Zealand White rabbits and evaluated for possible associations with spermatogenic efficiency as well as with volume density and number of Leydig cells. Testicular tissue was processed histologically and histometry was performed in order to quantify germ cells, Sertoli cells and Leydig cells. Spermatogenic efficiency, reported as the ratios among germ cells (spermatogonia, primary spermatocytes and round spermatids) and by the ratio of germ cells to Sertoli cells, was not associated with testosterone levels. However, Leydig cell parameters such as number of Leydig cells per gram of testis, total number of Leydig cells per testis and percent cell volume of Leydig cell nuclei were correlated significantly with testosterone levels. The statistically significant correlation (r = 0.82, P<0.05) observed between testosterone levels and the number of Leydig cells per gram of testis suggests that, in the rabbit, the latter parameter can serve as a criterion for monitoring testosterone levels in this species under normal conditions. Correspondence

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BackgroundIn a previous study, we showed that a saponin mixture isolated from the roots of Ampelozizyphus amazonicus Ducke (SAPAaD) reduces urine excretion in rats that were given an oral loading of 0.9 % NaCl (4 ml/100 g body weight). In the present study, we investigated whether atrial natriuretic peptides (ANP) and renal ATPases play a role in the SAPAaD- induced antidiuresis in rats.MethodsTo evaluate the effect of SAPAaD on furosemide-induced diuresis, Wistar rats (250-300 g) were given an oral loading of physiological solution (0.9 % NaCl, 4 ml/100 g body weight) to impose a uniform water and salt state. The solution containing furosemide (Furo, 13 mg/kg) was given 30 min after rats were orally treated with 50 mg/kg SAPAaD (SAPAaD + Furo) or 0.5 ml of 0.9 % NaCl (NaCl + Furo). In the SAPAaD + NaCl group, rats were pretreated with SAPAaD and 30 min later they received the oral loading of physiological solution. Animals were individually housed in metabolic cages, and urine volume was measured every 30 min throughout the experiment (3 h). To investigate the role of ANP and renal Na+ pumps on antidiuretic effects promoted by SAPAaD, rats were given the physiological solution (as above) containing SAPAaD (50 mg/kg). After 90 min, samples of urine and blood from the last 30 min were collected. Kidneys and atria were also removed after previous anesthesia. ANP was measured by radioimmunoassay (RIA) and renal cortical activities of Na+- and (Na+,K+)-ATPases were calculated from the difference between the [32P] Pi released in the absence and presence of 1 mM furosemide/2 mM ouabain and in the absence and presence of 1 mM ouabain, respectively.ResultsIt was observed that SAPAaD inhibited furosemide-induced diuresis (at 90 min: from 10.0 ± 1.0 mL, NaCl + Furo group, n = 5, to 5.9 ± 1.0 mL, SAPAaD + Furo group n = 5, p < 0.05), increased both Na+-ATPase (from 25.0 ± 5.9 nmol Pi.mg-1.min-1, control, to 52.7 ± 8.9 nmol Pi.mg-1.min-1, p < 0.05) and (Na+,K+)-ATPase (from 47.8 ± 13.3 nmol Pi.mg-1.min-1, control, to 79.8 ± 6.9 nmol Pi .mg-1.min-1, p < 0.05) activities in the renal cortex. SAPAaD also lowered urine ANP (from 792 ± 132 pg/mL, control, to 299 ± 88 pg/mL, p < 0.01) and had no effect on plasma or atrial ANP.ConclusionWe concluded that the SAPAaD antidiuretic effect may be due to an increase in the renal activities of Na+- and (Na+,K+)-ATPases and/or a decrease in the renal ANP.

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Summary The mean rectal‐testicular temperature gradient of four Nelore zebus was 5.2 ± 0.8 °C. There was no difference in the rectal (38.8 ± 0.4 °C) and intratesticular (33.6 ± 1.0 °C) temperatures between animals lying in the sun and those in the shade. Zusammenfassung Rekto‐testikuläre Temperaturdifferenz bei Zebus Die mittlere Temperaturdifferenz zwischen Rektum und den Testikeln bei 4 Nelore‐Zebus betrug 5,2 ± 0,8 °C (Rektaltemperatur: 38,8 ± 0,4 °C, Intratestikulartemperatur: 33,6 ± 1,0 °C). Tiere, die an der Sonne lagen und solche, die sich im Schatten aufhielten, zeigten die gleiche Temperaturdifferenz. Résumé Différence de température recto‐testiculaire chez le zébu La différence de température moyenne entre le rectum et le testicule chez 4 zébus Nelore fut de 5,2 ± 0,8 °C (temp. rectale 38,8 ± 0,4 °C et temp. intratesticulaire 33,6 ±1,0 °C). Les animaux exposes au soleil et ceux maintenus à l'ombre ont présenté les mêmes différences de température. Resumen Diferencia de la temperatura recto‐testicular en cebús La diferencia de temperatura media entre recto y testículos era en 4 cebús Nelore del orden de 5,2 ± 0,8 °C. (temperatura rectal: 38,8 ± 0,4 °C, temperatura intratesticular: 33,6 ±1,0 °C). Los animales que estaban tumbados al sol y los que permanecían a la sombra marcaban la misma diferencia de temperatura.