Immunocytochemical demonstration of contractile cells in the human ovarian follicle

Actin- and myosin-like immunoreactivity is found in cells located in the theca externa of the follicle wall of the human ovary, and corresponding to previously observed myoid cells. The immunocytochemical observation provides direct structural evidence that non-vascular contractile cells are also present in the follicle wall in humans. As expected, perifollicular blood vessels showed a positive immunoreaction for actin and myosin in their smooth muscle walls.     

Electrophysiological properties of the follicle wall in the pig ovary

The transmural potential difference and short-circuit current of the porcine Graafian follicle have been measured in an attempt to test whether antral fluid accumulates as a result of active transport of salt. The values obtained by mounting explants of follicle wall in Ussing chambers were close to zero and the specific electrical resistance was only 59 delta.cm2. The elemental composition of the follicular fluid was similar to that of ovarian venous plasma with the exception of follicular Na+ which was slightly more abundant. Bicarbonate concentrations were slightly lower in follicular fluids. These findings were interpreted as evidence that the follicular wall is a leaky epithelium and, therefore, any charge resulting from net ion transport will be shunted along low resistance paracellular pathways.     

Electrophysiological properties of the follicle wall in the pig ovary

Summary The transmural potential difference and short-circuit current of the porcine Graafian follicle have been measured in an attempt to test whether antral fluid accumulates as a result of active transport of salt. The values obtained by mounting explants of follicle wall in Ussing chambers were close to zero and the specific electrical resistance was only 59 ·cm². The elemental composition of the follicular fluid was similar to that of ovarian venous plasma with the exception of follicular Na⁺ which was slightly more abundant. Bicarbonate concentrations were slightly lower in follicular fluids. These findings were interpreted as evidence that the follicular wall is a leaky epithelium and, therefore, any charge resulting from net ion transport will be shunted along low resistance paracellular pathways.     

Action of juvenile hormone on the follicle cells ofRhodnius prolixus: Evidence for a novel regulatory mechanism involving protein kinase C

Summary Juvenile hormone (JH) is known to act on the membranes of the follicle cells ofRhodnius, activating a specific Na⁺, K⁺-ATPase. This leads to a decrease in volume of the cells and the appearance of spaces between them (patency). The addition of an inhibitor of protein kinase C, 1-(5-isoquinolinylsulfonyl)-2-methylpiperazine (H-7), to the medium in vitro inhibits the action of JH on the follicle cells. PDBU (phorbol-12,13-dibutyrate) mimics the action of JH in vitro and the response of the follicle cells to, PDBU is blocked by ouabain. It is concluded that the activation of protein kinase C is a required step in the chain of events leading to activation of the JH-dependent ATPase and set in train by the binding of JH to the membrane.     

3H-thymidine incorporation (DNA synthesis) and radiotoxicity in the ovary of the Japanese quail before and during follicle formation

No evidence was found for ribosomal DNA amplification in the oocytes of the Japanese quail, before or during folliculogenesis. DNA synthesis in the somatic cells, involved in follicle formation, starts at the medullar side of the basement membrane. The localized sterilization of the quail ovary after administration of 3H-thymidine (3H-TdR) seems to be due to radiation-induced lesions in the follicle forming somatic cells, rather than to direct radiation damage of the oocyte.     

A potential difference across mouse ovarian follicle

Summary A small potential difference (antrum positive) has been measured with fine-tipped glass microelectrodes across the epithelial cell layers of the mouse ovarian follicle wall. As ovulation approached the potential in the antrum became more positive compared to the outside. Metabolic inhibitors and locally active hormones also altered the potential difference. The ionic basis and the significance of the potential difference are unknown.     

Origin of ovarian follicle cells in birds

Summary In the embryonic Japanese quail ovary, transplanted on chicken chorioallantoic membrane (CAM), follicle cells are derived from somatic cells of the ovarian surface epithelium. No evidence was found for a contribution of other cell groups of the quail ovary in the formation of follicle cells. This may be demonstrated on PAS stained sections, by following the transfer of carbon particles, initially applied on the surface epithelium.The author is very grateful to Prof.L. Vakaet, R.U.C.A. Antwerp, for his valuables suggestions, and to MissC. van Hoecke for her technical assistance.     

Histopathological effect of thiourea on the ovarian tissues of Sarcophaga ruficornis (Fabr.).

The primary target of thiourea in female Sarcophaga are the follicles in the ovarioles. The follicle cells as a result become syncytial and their nuclei get pycnotic, inhibiting the transport of nutrient material into the nurse cells and of yolk into the oocytes. The subnormal eggs produced are not viable.     

3H-Thymidine incorporation (DNA synthesis) and radiotoxicity in the ovary of the Japanese quail before and during follicle formation

Summary No evidence was found for ribosomal DNA amplification in the oocytes of the Japanese quail, before or during folliculogenesis. DNA synthesis in the somatic cells, involved in follicle formation, starts at the medullar side of the basement membrane. The localized sterilization of the quail ovary after administration of³H-thymidine (³H-TdR) seems to be due to radiation-induced lesions in the follicle forming somatic cells, rather than to direct radiation damage of the oocyte.The author is very grateful to Prof. Dr L. Vakaet, R.U.C.A.—Antwerpen, for his valuable suggestions and to Mrs D. De Wolf-Van Rompaey for her excellent technical assistance.     

Histopathological effect of thiourea on the ovarian tissues ofSarcophaga ruficornis (Fabr.)

Summary The primary target of thiourea in femaleSarcophaga are the follicles in the ovarioles. The follicle cells as a result become syncytial and their nuclei get pycnotic, inhibiting the transport of nutrient material into the nurse cells and of yolk into the oocytes. The subnormal eggs produced are not viable.     

Inducement of blood vessel formation by ovarian extracts from mice injected with gonadotropins

Summary Ovarian extracts prepared from immature mice injected with human chorionic gonadotropin (hCG) and pregnant mare serum gonadotropin (PMSG) were assayed for angiogenic activity. The assay method consisted of implanting a film coated with ovarian extracts to the lateral wall of the m.rectus abdominus of a mouse for 20 days and examining the site for vascularization. The higher angiogenic activity obtained with PMSG-treated extract may be related to its follicle stimulating activity.Acknowledgment. Part of this work was supported by a grant from The Ministry of Education, Japan (No. 576165).     

In vitro morphological characterization of the bursal reticuloepithelial (REp) cells of chicken

Summary The REp cells of the bursa follicle medulla of chicken were isolated in vitro. Culture of the REp cells was maintained over a period of 10 days and the cells were observed at 3 and 10 days by means of transmission electron microscopy (TEM) and immunofluorescence. The use of an anticytokeratin monoclonal antibody confirmed their epithelial nature. TEM observations showed the presence of desmonsomes and tonofilaments, which are characteristic of epithelial cells. Furthermore, to some extent the cells regenerated in vitro the network they form in vivo. Though the growth rate becomes slower with time, the features of the REp cells do not significantly change.     

In vitro morphological characterization of the bursal reticuloepithelial (REp) cells of chicken.

The REp cells of the bursa follicle medulla of chicken were isolated in vitro. Culture of the REp cells was maintained over a period of 10 days and the cells were observed at 3 and 10 days by means of transmission electron microscopy (TEM) and immunofluorescence. The use of an anticytokeratin monoclonal antibody confirmed their epithelial nature. TEM observations showed the presence of desmosomes and tonofilaments, which are characteristic of epithelial cells. Furthermore, to some extent the cells regenerated in vitro the network they form in vivo. Though the growth rate becomes slower with time, the features of the REp cells do not significantly change.     

Ultrastructure of the oocyte follicles in the crustacean amphipod Orchestia gammarellus (Pallas)]

The follicle cells of the Crustacean Amphipoda Orchestia gammarellus produce syntheses at the level of the ergastoplasm and the Golgi body. No secretary cycle is observed. A complex but permeable network of intercellular spaces provides a path for possible transfollicular penetration for the exogenous fraction of the vitellus.     

The distribution of α2β1, α3β1 and α6β4 integrins identifies distinct subpopulations of basal keratinocytes in the outer root sheath of the human anagen hair follicle

The human hair follicle is composed of different concentric compartments, which reflect different programmes of differentiation. Using monoclonal antibodies against α2β1 and α3β1 integrins we demonstrated a shift in their expression, from a basolateral distribution in the basal cells of the lower outer root sheath, to an apicolateral expression in the upper outer root sheath, as in epidermis. This shift takes place in a transition zone, localized to the midpart of the follicle. The distinct basolateral distribution of α2β1 and α3β1 integrins in the lower portion of the outer root sheath coincides with the presence of basal cell protrusions and is probably linked to the presence of the vitreous membrane which surrounds the bottom part of the anagen human hair follicle. Moreover, we showed that the expression of α6β4 integrin is discontinuous along the hair follicle and coincides with that of laminin 5. Together these results establish that within a given compartment – namely the outer root sheath – several domains can be clearly identified, which probably reflect the onset of successive differentiation pathways along the hair follicle. Received 17 January 1997; received after revision 18 February 1997; accepted 24 February 1997     

Follicles development in the foetal human ovary.

In the foetal human ovary, diameters of oocyte and follicle, as well as those of oocyte and nucleus, are found to be positively and linearly correlated with each other. Follicle diameter and number of granulosa cells also show a positive and linear relationship. Finally, in all ovaries examined, from 5 months after conception onwards, small antral follicles were assessed.     

Follicles development in the foetal human ovary

Summary In the foetal human ovary, diameters of oocyte and follicle, as well as those of oocyte and nucleus, are found to be positively and linearly correlated with each other. Follicle diameter and number of granulosa cells also show a positive and linear relationship. Finally, in all ovaries examined, from 5 months after conception onwards, small antral follicles were assessed.     

Nerves and muscles regulating feather follicle movements in the chicken

Summary It was found that most feather follicles possess more than a single muscle system but only single nerve endings were observed in a feather follicle. It seems that muscles exist which antagonize each other. Anastomoses of nerves orginating from different sources and flowing of mixed nerves into the feather follicle could explain the antagonistic action of the muscles on the feather follicle.Partially supported by a grant from the Israel Egg and Poultry Board.     

Apoptosis occurs in granulosa cells but not cumulus cells in the atretic antral follicles in pig ovaries

The porcine antral follicles, 3–6 mm in diameter, were dissected from the ovaries of mature pigs, and then granulosa and cumulus cells were isolated from each follicle. In atretic follicles, high activity of neutral Ca²⁺/Mg²⁺-dependent endonuclease and DNA ladder formation, estimated by electrophoresis, were noted in granulosa cells but not in cumulus cells. Extremely low activity of the endonuclease and no DNA ladder formation were observed in both types of cells obtained from healthy follicles. Moreover, apoptotic cells were observed histochemically among granulosa cells only. A good correlation (r=0.987) between the endonuclease activity of granulosa cells and the progesterone/estradiol ratio of follicular fluid in each follicle was found. These results suggest that apoptosis occurs in granulosa cells but not cumulus cells in the atretic antral follicles in pigs.     

Einbau von H3-d-glucose während der Oogenese beiApis mellifica L.

Summary The incorporation of tritiated glucose into the ovary of honey bee queens was studied by autoradiography. During the last stages of oogenesis, the synthesis of respectable amounts of glycogen was found in the reticuloplasm of the developing eggs. The follicle epithelium and also the nurse cells only appeared more lightly and transitory labelled at medium stages. An hypothesis was established concerning an antagonism of protein and polysaccharide formation in the cytoplasm corresponding to the rather late occurrence of glycogen in insect oogenesis.