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Morphological investigations of the mammary gland in the beagle bitch during pregnancy and lactation
THERIOGENOLOGY
Ibach, B., L. Weissbach, B. Hilscher (Urologische Universitatsklinik Bonn, Direktor: Prof. Dr. W. Vahlensieck, D5300 Bonn, Benusberg und Institute fur Lufthygiene und Silikoseforschung an der Universitat Dfisseldorf, D 4000 DIsseldorf, Gurlittstrasse 53) Phases of Normal Spermatogenesis
in the Dog
In general, the assignment of phases of spermatogenesis in the rat as described by Clermont and coworkers is used as guidance for schemes of spermatogenesis in other species. In essence, spermatogenesis in the dog follows patterns very similar to those in the rat: The number of differentiating spennatogonial generations and of the subsequent spennatogenetic cells are equal in both species. Biological variations are more pronounced in the dog, within and between individuals. For a precise accounting, spennatogenesis in the dog was subdivided in 10 phases: Phase I commences with the elongation of spermatides. Maturation divisions are seen in phases Va and Vc. In phases I, III, v, VI, VII and VIII, the generations of cells of the successive spermatogonial rows divide (Al - A4, Im and B).
Wrobel, K.H., M.D. El Etreby & P. GClnzel (Institut far Anatomie der Universith, 0-8400 Hegensburg, Universitltsstrasse 31 and Dept. far experimentelle Toxikologie der Schering AG, D-1000 Berlin 65, Sellerstrasse 12) Morphological Investigations of the Mammary Gland in the Beagle Bitch During Pregnancy and Lactation On day 40 after conception, active mammary gland growth is virtually concluded. Alveolar formation from solid duct endings by the formation of luminal spaces are accomplished, and the secretion is initiated. During the last trimester (days 50 to 60) the mammary gland is enlarged solely by the distention of the alveolar spaces by stored secretions. Until day 40, no lipids are detectable by histochemical methods, but during the last trimester a significant lipid content of the epithelium and the secretion in the alveoli is seen. Histochemically, the enzymes of the oxydative metabolism (SDH, ICDH, CYT-OX) show increases in the secretory tissues until day 40; from day 40 to 60, their activity is markedly reduced but increases significantly with lactation. The behavior of myoepithelial cells can be shown best by determination of the alkaline phosphatase: Only during the last trimester and lactation the typical basket-cell formation is visible.
OCTOBER 1975
VOL. 4 NO. 4
137
Ibach, B., L. Weissbach, B. Hilscher (Urologische Universitatsklinik Bonn, Direktor: Prof. Dr. W. Vahlensieck, D5300 Bonn, Benusberg und Institute fur Lufthygiene und Silikoseforschung an der Universitat Dfisseldorf, D 4000 DIsseldorf, Gurlittstrasse 53) Phases of Normal Spermatogenesis
in the Dog
In general, the assignment of phases of spermatogenesis in the rat as described by Clermont and coworkers is used as guidance for schemes of spermatogenesis in other species. In essence, spermatogenesis in the dog follows patterns very similar to those in the rat: The number of differentiating spennatogonial generations and of the subsequent spennatogenetic cells are equal in both species. Biological variations are more pronounced in the dog, within and between individuals. For a precise accounting, spennatogenesis in the dog was subdivided in 10 phases: Phase I commences with the elongation of spermatides. Maturation divisions are seen in phases Va and Vc. In phases I, III, v, VI, VII and VIII, the generations of cells of the successive spermatogonial rows divide (Al - A4, Im and B).
Wrobel, K.H., M.D. El Etreby & P. GClnzel (Institut far Anatomie der Universith, 0-8400 Hegensburg, Universitltsstrasse 31 and Dept. far experimentelle Toxikologie der Schering AG, D-1000 Berlin 65, Sellerstrasse 12) Morphological Investigations of the Mammary Gland in the Beagle Bitch During Pregnancy and Lactation On day 40 after conception, active mammary gland growth is virtually concluded. Alveolar formation from solid duct endings by the formation of luminal spaces are accomplished, and the secretion is initiated. During the last trimester (days 50 to 60) the mammary gland is enlarged solely by the distention of the alveolar spaces by stored secretions. Until day 40, no lipids are detectable by histochemical methods, but during the last trimester a significant lipid content of the epithelium and the secretion in the alveoli is seen. Histochemically, the enzymes of the oxydative metabolism (SDH, ICDH, CYT-OX) show increases in the secretory tissues until day 40; from day 40 to 60, their activity is markedly reduced but increases significantly with lactation. The behavior of myoepithelial cells can be shown best by determination of the alkaline phosphatase: Only during the last trimester and lactation the typical basket-cell formation is visible.
OCTOBER 1975
VOL. 4 NO. 4
137