ABSTRACT
Testes of foetal pigs between 26 to 35 days post coitum (p.c.) were investigated histochemically and ultrastructurally. Diaphorase and delta 5-3 beta-hydroxysteroid dehydrogenase activities were studied using, respectively, NADH and pregnenolone and dihydroxy androsterone as substrates. Ultrastructurally, attention was focused on the development of mesenchymal cells and on the sustentacular cells in the primitive sex cords in an attempt to detect the origin of Leydig cells. Histochemically there is a concentration of activity toward the interstitium with increasing age. Also the reactions increase in intensity. Ultrastructurally no evidence for Leydig cell development from Sertoli cells could be observed. Mesenchymal cells between the sex cords show a development toward Leydig cells. This is absent in mesenchymal cells in the future tunica albuginea. Before 30 days p.c. no 'true' Leydig cells can be observed morphologically. The role of the rough endoplasmic reticulum/mitochondrial complex, which is present in many mesenchymal and sustentacular cells, is discussed.
Subject(s)
Fetus/ultrastructure , Testis/ultrastructure , 3-Hydroxysteroid Dehydrogenases/analysis , Animals , Dihydrolipoamide Dehydrogenase/analysis , Germ Cells/ultrastructure , Histocytochemistry , Leydig Cells/ultrastructure , Male , Microscopy, Electron , Sertoli Cells/ultrastructure , SwineABSTRACT
Ovarian development was studied in control and decapitated pig fetuses. Fetuses were decapitated at 42 days postcoitum. At 51, 61, 74, 90 and 112 days postcoitum decapitated and control females were collected. Ovarian weight gradually increased during development in control animals. Deprivation of pituitary hormones as a result of fetal decapitation did not cause a decline in ovarian weight increase. Germ cell maturation in control and decapitated fetuses proceeded in a similar fashion, with secondary follicles being the most advanced stage. Enzyme histochemical activity was present in the primary interstitial gland cells and in granulosa cells and was similar in normal and decapitated fetuses. Both NADH diaphorase activity and 3 beta-hydroxysteroid dehydrogenase activity increased from 51 to 74 days and remained relatively constant thereafter. Since fetal decapitation in the pig hardly influences ovarian development, pituitary dependency of the fetal ovary in the pig is unlikely.
Subject(s)
Ovary/embryology , 3-Hydroxysteroid Dehydrogenases/analysis , Animals , Dihydrolipoamide Dehydrogenase/analysis , Female , Meiosis , Organ Size , Ovary/metabolism , Pituitary Hormones/physiology , Pregnancy , SwineABSTRACT
Serum FSH concentrations were measured in fetal and prepubertal pigs between 40 days postcoitum and 25 weeks after birth. In addition, serum FSH was estimated in prepubertal, unilaterally cryptorchid, freemartin and castrated pigs. The average serum FSH concentrations in male and female fetuses was low (less than 2 ng/ml) until 80 days p.c. During the remaining fetal period, concentrations in females were elevated (7.9 +/- 0.4 ng/ml) and remained fairly constant after birth (16.3 +/- 0.8 ng/ml). In the male, serum FSH concentrations gradually rose to 22.5 +/- 5.5 ng/ml during the first 3 weeks after birth and declined thereafter. The changes in FSH concentrations in male pigs are reflected in gonadal-development. In contrast, in fetal and prepubertal females, ovarian development seems not to be influenced by changes in serum FSH concentrations. Unilateral cryptorchidism did not affect serum FSH concentrations. After castration, however, concentrations rose significantly. In freemartin pigs concentrations were similar to those in female pigs.
