Summary. Epididymal sperm reserves were determined in 6 sexually mature goats. The numbers of spermatozoa in the caput, corpus and cauda epididymidis were 1\m=.\90 \ m=+-\ 0\ m=. \16, 0\m=.\66\ m=+-\ 0\m=.\04and 6\m=.\18 \m=+-\ 0 \ m= . \ 9 1 \m=x\ 109 respectively and they represented 21\m=.\7, 7\m=.\5and 70\m=.\8% respectively of the sperm reserve on that side. The total epididymal sperm reserve/male was about 17\m=.\5\m=x\109 spermatozoa.

No abstract

The fact that melatonin, a pineal substance, causes a depression in thyroid function of prepuberal rats has been reported. A possible site of this action on the thyroid gland has been studied by estimating the TSH content of blood and hypophysis in rats from 35 days to 65 days of age. Haemagglutination-inhibition technique has been used to assay very small amounts of TSH in plasma. Rats receiving 100 μg of melatonin daily for 10 days were sacrificed at 35, 45, 55 and 65 days of age. The mean thyroid weight of each group was markedly higher than that of the corresponding controls. The plasma TSH/ml level was higher in experimental groups, with a marked decrease (0.10 > P > 0.05) in TSH/mg of hypophysis (wet), especially at 45 and 55 days of age. Rats similarly treated with 400 μg/100 g body weight of tapazole daily for 10 days and sacrificed at 45 and 55 days of age showed higher plasma and lower hypophyseal TSH levels than the controls and the results were comparable to those of the melatonin treated groups. The dry-fat-free tissue of the thyroid glands of the melatonin treated groups were higher than the corresponding controls and their DNA content was significantly higher (0.050 > P > 0.025) also, indicating hyperplasia and hypertrophy of the thyroid glands resulting from the action of melatonin. The histological picture of the melatonin treated animals showed goitrogenic effect. It may be concluded from these data that melatonin exerts its regulatory effect on TSH secretion directly acting on the thyroid gland and in some way inhibiting thyroid hormone synthesis or release.

Angiotensin Converting Enzyme (ACE) is present in the testis, epididymis and semen. But no physiological role has been assigned to ACE. The present study is to indicate possible role of ACE in capacitation. Semen was incubated in minimum capacitation in vitro. Epinephrine and serotonin were added t o note the effect of biogenic amines. The leakage of ACE was very high in capacitated spermatozoa compared to spermatozoa in saline. Presence of amines in the saline induced ACE leakage. These results indicate that ACE may be involved in the capacitation. ACE im Samen und seine mogliche Rolle bei der CapacitationZusammenfassung: ACE kommt sowohl im Hoden als auch im Nebenhoden und im Samen vor. Bisher ist dem ACE allerdings keine physiologische Rolle zugewiesen worden. In der vorgelegten Studie sollte die mogliche Rolle des ACE bei der Capacitation dargelegt werden. Hierzu wurden gewaschene Spermatozoenpellets in physiologische Kochsalzlosung eingelegt und dann zentrifugiert. Die Inkubation erfolgte in eine MCM-Losung zur Induktion der Capacitation in vitro. Epinephrin und Serotonin wurden zur Beobachtung des Effektes der biogenen Amine zugesetzt. Der Verlust von ACE war bei capacitierten Spermatozoen sehr hoch gegeniiber den Spermatozoen in Kochsalzlosung. Die Anwesenheit der Amine in der Kochsalzlosung induzierte den ACE-Verlust. Die vorgelegten Ergebnisse bedeuten, d& ACE in den Capacitationsvorgang involviert sein durfte.

Summary:  Angiotensin converting enzyme (ACE) activity has been reported in testis and epididymis of seven different animal species. Among all the species, the mouse testis and epididymis showed the highest converting enzyme activity followed by rat testis and epididymis. The lowest activity was detected in buffalo testis and rabbit epididymis. Most of the testicular enzyme was found concentrated in the 107,00 xg sediment while the epididymal enzyme was equally distributed between sediment and supernatant. ACE levels of different regions of the rat testis and epididymis was analyzed. The gradient of ACE was found increasing from caput to cauda. A major fraction of testicular and epididymal ACE activity was found in their respective fluid. ACE appeared only in mature rats, rabbits and mice testis and epididymis. Sexually stimulated rabbits showed significant ACE increase in the testis. In vitro characterization studies were conducted. Zusammenfassung:  Angiotensin‐Converting‐Enzym in den Hoden und Nebenhoden von Säugetieren Es wird berichtet über die Aktivität des Angiotensin‐Converting‐Enzyms (ACE) in den Hoden und Nebenhoden sieben verschiedener Tierarten. Von alien Arten zeigten die Hoden und Nebenhoden der Maus die höchste Enzymaktivität, gefolgt von den Hoden und Nebenhoden der Ratte. Die niedrigste Aktivität wurde in Büffelhoden und Kaninchennebenhoden gefunden. Der größte Teil des Hodenenzyms was in dem UI‐trazentrifugensediment (107.000 × g) konzentriert, wohingegen das Nebenhodenenzym gleichmäßig auf das Sediment und den Überstand verteilt waren. Es wurden die ACE‐Konzentrationen verschiedener Anteile des Rattenhodens und ‐nebenhodens bestimmt. Die ACE‐Konzentration nahm dabei vom Kopf zum Schwanz hin zu. Der Hauptanteil der Hoden‐ und Nebenhoden‐ACE‐Aktivität wurde in den jeweiligen Flüssigkeitsanteilen gefunden. Das ACE tritt nur in geschlechtsreifen Ratten‐, Kaninchen‐ und Mäusehoden und ‐nebenhoden auf. Sexuell stimulierte Kaninchen wiesen einen signifikanten ACE‐Anstieg in den Hoden auf. Die Untersuchungen zur in‐vitro‐Bestimmung wurden aufgezeigt.