The pesticide heptachlor affects steroid hormone secretion in isolated follicular and luteal cells of rat.

Heptachlor, a chlorinated hydrocarbon pesticide, suppresses the production of progesterone and estradiol in the female rat in vivo or in isolated ovaries in vitro. In this study the effect of heptachlor on steroid hormone production by isolated rat luteal and follicular cells, in the presence of two precursor hormones was investigated. Ovaries were isolated from anesthetized mature normocyclic virgin rats (3 to 4 months old), under sterile conditions. Corpora lutea and follicles were microscopically dissected out and separately enzymatically dispersed with collagenase at 37 degrees C. Viable cells collected after centrifugation were used at a concentration of approximately 2.5 x 10(5) cells/10 mL. Both luteal and follicular cell preparations were separately incubated overnight (15 h) at 37 degrees C in the presence of pregnenolone (P5) and androstenedione (A4) at a concentration of 6.0 nmol/L each, and heptachlor at either 0.12 microg/mL (low dose) or 1.20 microg/mL (high dose) (test cells) or in the absence of heptachlor (control cells). At the end of the incubations, progesterone and estradiol 17beta levels were analyzed in the incubation media. The results indicate that heptachlor significantly suppressed the production of both progesterone and estradiol in both cell types in a dose related manner even in the presence of A4 and P5 as precursor hormones (P<0.05).

Ultrastructure of the chorioallantoic placenta and chorionic vesicles of the lesser bush baby (Galago senegalensis).

The ultrastructure of the chorioallantoic placenta of the lesser bush baby (Galago senegalensis) has been studied. The placenta was shown to be of the diffuse, epitheliochorial and adeciduate type. The trophoblasts of the chorionic villi, other than those lining the chorionic vesicles, were characterized by the presence of many lipid droplets. In the later stage of gestation, the fetal capillaries indented the trophoblastic epithelium reducing the distance between fetal and maternal circulations. In addition chorionic vesicles were observed. The trophoblasts lining the chorionic vesicles have outward bulging apical surfaces. There are clefts between these cells and this region is occupied by microvilli of adjacent cells. Several layers of fusiform cells that did not extend up into the cores of the chorionic vesicle villi formed the outer component of the vesicular wall. Granulated cells were observed within the maternal connective tissue and their possible role is discussed.

Placenta and fetal membranes of the four-toed elephant shrew, Petrodromus tetradactylus.

The four-toed elephant shrew is the only extant member of the genus Petrodromus. Some features of its placentation are found in other elephant shrews and may be important in consolidating the elephant shrews in the order Macroscelidea. These include implantation in an embryo chamber at the caudal end of the uterine horn; a large yolk sac; a large, lobulated allantoic sac; a distinct layer of proliferative trophoblastic cells between the labyrinthine and spongy zones of the placenta; an accessory epitheliochorial placenta; and the formation of a mesoplacenta by the decidua basalis. Of particular note are the large granulated cells that occupy the walls of decidual, myometrial and mesometrial arteries. They appear to be uterine natural killer cells. The persistence of a relatively large yolk sac and a large lobulated allantoic sac is a feature which Petrodromus and other elephant shrews share with other members of the superordinal clade Afrotheria.

Placentation in species of phylogenetic importance: the Afrotheria.

Afrotheria, one of four mammalian superorders, comprises elephants, sea cows, hyraxes, aardvark, elephant shrews, tenrecs and golden moles. Their placentas either form an equatorial band or are discoid in shape. The interhemal region, separating fetal and maternal blood, is endotheliochorial in elephants, aardvark and possibly the sea cows, but hemochorial in the remaining orders. There is a secondary epitheliochorial placenta in elephant shrews while a similar structure in tenrecs erodes maternal tissues. Specialized hemophagous regions are a striking characteristic of some of these placentas yet absent in hyraxes, elephant shrews, and golden moles. It is possible that the common ancestor of the Afrotheria had an endotheliochorial placenta. Establishment of a hemochorial condition, as seen in rock hyraxes, elephant shrews, tenrecs, and golden moles, would be a more recent development. The elephant, manatee, and aardvark all have circumferential placentas. Thus the formation of a discoid placenta with a more or less extensive secondary placenta in elephant shrews and tenrecs would also be a derived state.

Early testicular response to intraperitoneal administration of ethane dimethanesulphonate (EDS) in the goat (Capra hircus).

Early morphological changes in the goat testis after a single intraperitoneal injection of ethane dimethanesulphonate (EDS) were investigated using both light and electron microscopy. The compound was administered at two dose levels: 75 mg/kg and 25 mg/kg. While the former resulted in some deaths due to toxicity, the latter had no noticeable toxic effects on the animals. The testicular effects at both dose levels were similar. Six (6) days post-treatment, Leydig cells were refractory to EDS challenge but there was a marked disruption of spermatogenesis. These Leydig cells exhibited ovoid or irregularly round nuclei, abundant cytoplasm containing spherical, ovoid or elongate mitochondria and a preponderance of smooth endoplasmic reticulum typical of the normal cells. Lipid droplets were rare. In the seminiferous tubules germ and Sertoli cell degeneration was observed. Changes in the germ cells included: spermatogonial degeneration, condensed chromatin in leptotene spermatocytes and failure of chromatin re-organization resulting in the formation of clumps in the cells at the telophase stage of cell division (stage 4 of the seminiferous cycle). The nuclear envelope of primary spermatocytes showed marked irregularity and there was an overall reduction in cell size. There was peripheral re-distribution of chromatin in developing spermatids of stages 1, 2 and 5, often resulting in thick margination along the nucleolemma and leaving a pale nucleoplasm. An accompanying retention of maturation phase spermatids in stage 2 tubules was also observed. Sertoli cells exhibited extensive accumulation of intracytoplasmic vesicles, obscuring the rest of the organelles. Intercellular vacuoles also occurred within the epithelium. The results suggest that while EDS does not have any effect on goat Leydig cells, it causes severe disruption of the spermatogenic process. Furthermore, it is concluded from the results that the optimum dose in this species is 25 mg/kg.

Morphological characterization of the seminiferous cycle in the goat (Capra hircus): a histological and ultrastructural study.

The cycle of spermatogenesis/seminiferous cycle was investigated in the goat testis using both light and electron microscopy techniques. Using the various cell associations and the accompanying changes in spermatid shape and location, the cycle was divided into eight (8) successive stages. The cycle began with the accomplishment of spermiation (stage 1) and ended with apical migration and close attachment of late maturation phase spermatids at the Sertoli cell apex accompanied by adluminal retention of residual bodies with dense staining inclusions (stage 8). The early stages of the cycle (stages 1-4) were therefore characterized by the presence of only one generation of spermatids, the second one appearing only after the division of secondary spermatocytes in stage 4. Consequently, stages 5-8 had two generations of spermatids; Golgi or cap phase as well as maturation phase spermatids. Although stages 5 to 7 appeared as distinct entities, stages 6 and 7 were rather short-lived and considered as continuations of stage 5. Therefore, the 8 stages of the cycle in the goat were further condensed into 6 main divisions. The duration of each stage was estimated by the frequency of occurrence in sections. Among these, stage 1 had the highest frequency (34%) followed by stages 5-7 (27%). Stages 8 and 4 had the shortest frequency (up to 9%) while stages 2 and 3 had 13% and 12% respectively. These results indicate that, like most domestic species, goats have a cycle of 8 stages with 6 main divisions, the longest being stage 1.

Morphology of a six-legged goat with duplication of the intestinal, lower urinary, and genital tracts.

BACKGROUND: An adult female goat with rare malformations, which consisted of duplication of the intestinal, lower urinary, and genital tracts as well a pair of parasitic appendages, is presented. METHODS: A complete dissection was performed on a moribund female goat (Capra hircus). RESULTS: The animal had a normal body with a parasitic attachment located within the pelvic region. This attachment was represented by an ovoid, trunk-like, adipose mass that lacked internal organs or vertebrae but that had two fairly well-developed limbs with the normal components of hind limbs. There was duplication involving the external and internal genitalia, the urethra, the urinary bladder, and portions of the small intestine as well as the large bowel, including the anal openings. CONCLUSIONS: An autosite with a duplication involving the hindgut and paramesonephric anlages was identified. These features were compatible with life in utero and postutero and emanated from incomplete twinning (heteropagus twins). A review of the literature also suggests that heteropagus twins are a very rare abnormality in both domestic animals and humans.

In vivo and in vitro effects of graded doses of the pesticide heptachlor on female sex steroid hormone production in rats.

Adult female Sprague-Dawley rats were injected with corn oil or 5 mg, 20 mg, 25 mg or 30 mg per kg body weight of heptachlor solution every other day for up to 18 days. The rats were killed at the end of the experimental period, and blood samples were assayed for progesterone and oestrogen by radioimmunoassay. Ovarian cells from the rats were isolated and incubated either on their own, or in the presence of LH or FSH, and production of progesterone and oestrogen determined. Control incubations consisted of cells from corn oil-treated rats. The latter were also incubated on their own or in the presence of LH or FSH. Heptachlor significantly suppressed blood progesterone and oestradiol levels (P < 0.05 to P < 0.001), the degree of suppression depending on the dose and the stage of the oestrous cycle in which samples were obtained. Production of oestradiol by ovarian cells from heptachlor-treated rats was lower than for corn oil-treated controls. Cells from rats treated with low doses of heptachlor (5 mg per kg body weight) showed an increased production of progesterone, while high doses (> 20 mg per kg body weight) suppressed production.

Effects of graded doses of the pesticide heptachlor on body weight, mating success, oestrous cycle, gestation length and litter size in laboratory rats.

Adult female Sprague-Dawley rats were injected with 5 or 20 mg/kg body weight heptachlor solution every other day for up to 18 days. They were weighed every day and the stage of oestrus determined by vaginal smears. One experimental group was mated and pregnancy characteristics studied. Heptachlor affected body weights, cycle patterns, length of gestation period and litter sizes in a dose-related manner. At a dose of 20 mg/kg body weight, heptachlor caused a significant decrease in average body weight (P < 0.01), disrupted and/or prolonged oestrous cycles, decreased mating success (P < 0.001), slightly increased gestation length (P < 0.05) and decreased litter size (P < 0.01).

Effects of 6-hydroxydopamine on testosterone production by mouse leydig cells in vitro.

Increasing doses (15 to 1000 micrograms/ml) of 6-hydroxydopamine (6-OHDA) stimulated, then suppressed testosterone production by mouse leydig cells incubated for 3 h in vitro. The stimulating doses ranged between 50 and 100 micrograms/ml, with maximal effects occurring at 30 to 60 minutes after the start of the treatments. At doses of 500 micrograms/ml, 6-OHDA exhibited inhibitory effects. When added to leydig cell incubations together with stimulating doses of luteinising hormone (LH), 1-(3',4'-dihydroxyphenil)2-isopropylaminoethanol (L-isoproterenol) or 8-bromoadenosine 3':5'-cyclic monophosphate (8-Br-cAMP), 6-OHDA abolished the effects of the latter compounds. Prolactin and prostaglandin E2 (PGE2) inhibited the stimulating effects of 8-Br-cAMP but not LH. It is proposed that the actions of 8-OHDA affect intracellular sites yet to be identified, thereby inhibiting testosterone production by mouse Leydig cells. Some of the actions of 6-OHDA seem to be medicated via beta-adrenergic receptors as the latter abolishes the stimulatory effects of L-isoproterenol, a potent beta-adrenergic agonist. However, the inability of stimulatory doses of LH and 8-Br-cAMP to reverse the inhibitory effects of 6-OHDA point to the possibility that other actions of 6-OHDA may be relayed via a second messenger system separate from that involving cAMP.

Ultrastructural study of the testis of non-breeding naked mole-rat (Heterocephalus glaber, Ruppell).

The testicular structure of the wild caught naked mole rat was studied. It comprises of a large volume of lipid-rich interstitial cells of Leydig among which are few scattered seminiferous tubules. In addition, the interstitial cells possess elongated mitochondria and vast network of smooth endoplasmic reticulum (sER). The Golgi apparatus (GA) apparently is not conspicuous or well developed. All stages of spermatogenesis occur in the seminiferous tubules although the mature forms (secondary spermatocytes, spermatids and spermatozoa) are few. Sertoli cells show an irregular nucleus, mitochondria oriented perpendicular to the basement membrane, a vast network of endoplasmic reticulum with sER as the predominant form and lipid droplets. The ultrastructural features of Leydig cells seem to suggest a steroidogenic capacity although the vast accumulation of lipid droplets may imply impaired utilisation of cholesterol reservoir as a result of pituitary hormonal imbalance or (and) the local paracrine influence by Sertoli cells. The cause of slow-down in spermatogenesis is still unclear but may also be under the influence of pheromonal cues or the local paracrine control. Sertoli cell features point towards a role of synthesis and secretion.

Impairment of gonadal function and epididymal sperm passage following cremaster muscle transection in the goat

Unilateral transection of cremaster muscle was done in young adults of the small East African goat. The animals were subsequently examined for libido; fertility; functional and morphological changes in the testis; semen characteristics and testosterone profile over a period of one year. Within three months of operation there was progressive testicular induration; oligospermia and reduction in fertility. It is concluded that cremaster transection impairs passage of spermatozoa from the seminiferous tubules to the epididymis. The blocked tubules on bursting lead to the formation of sperm granuloma and anti-bodies; the latter causing further damage to both testes

The interhemal membrane of the spotted hyena: an immunohistochemical reappraisal.

On the basis of specific immunohistochemical staining for vimentin and cytokeratin, we conclude that in the mature placenta of the spotted hyena the interhemal membrane is haemomonochorial rather than endotheliochorial, as in other carnivores. We concur that the intrasyncytial laminae are remnants of the maternal endothelial basal lamina.

Plasma testosterone in Trypanosoma congolense-infected Toggernburg goats.

Trypanosomiasis induces histological testicular degenerative changes leading to suppression of spermatogenesis in goats and laboratory animals. We present evidence associating these changes with trypanosome-induced endocrine dysfunction. Toggenburg goats were infected with approximately 100,000 trypanosomes. They were bled every 2 days, and the plasma testosterone was analyzed by radioimmunoassay. Testes were perfused with and fixed in Bouin's fixative for histological evaluation. The infected plasma samples showed depressed testosterone levels with episodic peaks reduced in both amplitude and frequency. Histological characteristics of the testicular and epididymal tissues revealed aspermic tubules and epididymides and desquamation of the tubular germinal epithelia. These testicular degenerative changes may be partly due to the depressed plasma testosterone levels.

An electron microscopic study of the chorioallantoic placenta and the subplacenta of the cane rat (Thryonomys swinderianus Temminck).

The ultrastructure of the cane rate chorio-allantoic placenta has been studied. In its thinnest regions the interhaemal membrane is composed of a single layer of syncytiotrophoblast, a common basal lamina, and the fetal capillary endothelium. Hence this is a haemomonochorial placenta. The cytotrophoblastic cells show many mitotic figures but they are never seen directly bounding the maternal blood spaces. The syncytiotrophoblast of the spongy zone is rich in dilated cisterns of granular endoplasmic reticulum and is also characterized by many 'intrasyncytial canaliculi'. The subplacenta consists of both cytotrophoblast and syncytiotrophoblast. The syncytiotrophoblast has numerous short microvilli projecting into the intercellular spaces, granular endoplasmic reticulum, a well-developed Golgi complex, and numerous electron-dense granules of uniform size. The intercellular spaces or lacunae contain a precipitate of moderate electron density which is similar in texture to the intracellular precipitate in the 'brush border' region of the syncytiotrophoblast. The similarities between the ultrastructure of the cane rat placenta and those of the guinea pig and chinchilla are discussed.

Histology of the chorioallantoic placenta of the golden-rumped elephant shrew (Rhynchocyon chrysopygus Gunther, 1881).

The chorioallantoic placenta of the golden-rumped elephant shrew, Rhynchocyon chrysopygus has been studied. The implantation is eccentric and mesometrial. The placenta is haemochorial and is divisible into 4 zones namely columnar, proliferative, spongy and basal trophoblastic zones. The proliferative zone, which is peculiar to the Macroscelididae, is present in the early and mid pregnancy but disappears in later stages. The presence of the basal trophoblastic zone, the absence of a true zone of degeneration, the absence of the "mesoplacentarium" (of Starck 1949) and the structure of the wall of the allantoic vessels differentiate Rhynchocyon from other elephant shrews that have been studied. The presence of large cells in the maternal blood spaces and in the lumen of decidual vessels is also reported but the fate of such cells is not yet known.

Electron microscopic study of the chorioallantoic placenta of the rock hyrax (Heterohyrax brucei).

The interhaemal membrane consisted of only two cellular elements: a single layer of cellular trophoblast and the fetal capillary endothelium. The hyrax is therefore one of the few mammals known to possess the cellular haemomonochorial type of placenta. The trophospongium was also cellular while the basal trophoblastic cells were strongly phagocytic. The giant multinucleate cells at the feto-maternal junction were ultrastructurally different from the trophoblast cells and showed no signs of degeneration. Their appearance suggests that they are of maternal rather than fetal origin.

The chorioallantoic placenta of the spotted hyena (Crocuta crocuta Erxleben): an electron microscopic study.

The histology and ultrastructure of the chorioallantoic placenta of the spotted hyena have been studied in three specimens obtained in the field and fixed promptly with glutaraldehyde. Observations revealed that the interhemal membrane at its minimal thickness is hemomonochorial, consisting of a continuous layer of syncytial trophoblast, a basal lamina, and fetal capillary endothelium. Cytotrophoblastic cells form a discontinuous layer beneath the syncytial trophoblast and are distinguished by the presence of numerous extracted lipid droplets in their cytoplasm. A network of extracellular spaces, incorrectly identified as cisternae of endoplasmic reticulum by earlier investigators, occurs beneath the maternal surface of the syncytial trophoblast. These spaces contain moderately dense, nonfibrillar material resembling the intrasyncytial lamina previously described only in the hemochorial placenta of certain bats. Hence, these spaces may contain remnants of maternal capillary basal lamina following displacement of the endothelium by extensions of syncytial trophoblast at an early stage of placental development.