Characterization of the pituitary gonadotroph cells of hypogonadal (hpg) male mice: comparison with normal mice

1982 ◽  
Vol 95 (3) ◽  
pp. 321-NP ◽  
Author(s):  
I. F. W. McDowell ◽  
J. F. Morris ◽  
H. M. Charlton

Hypogonadal (hpg) mice lack hypothalamic luteinizing hormone releasing hormone (LH-RH). Gonadotrophs from male hpg mice have been identified by immunocytochemistry for LH and quantitative electron microscopy allied with radioimmunoassay of the gonadotrophins. In comparison with those of normal mice, gonadotrophs in male hpg animals are less numerous and smaller, with less cytoplasm and rough endoplasmic reticulum and a smaller Golgi apparatus. They have fewer granules, especially those of larger (> 210 nm) diameter. Thus, in the absence of LH-RH, gonadotrophs can differentiate but remain relatively inactive.

1972 ◽  
Vol 6 (5) ◽  
pp. 481-486 ◽  
Author(s):  
Abba J Kastin ◽  
Andrew V Schally ◽  
Don S Schalch ◽  
Stanley G Korenman ◽  
M Clinton Miller ◽  
...  

1990 ◽  
Vol 68 (7) ◽  
pp. 1454-1467 ◽  
Author(s):  
K. M. Fry ◽  
S. B. McIver

Light and electron microscopy were used to observe development of the lateral palatal brush in Aedes aegypti (L.) larvae. Development was sampled at 4-h intervals from second- to third-instar ecdyses. Immediately after second-instar ecdysis, the epidermis apolyses from newly deposited cuticle in the lateral palatal pennicular area to form an extensive extracellular cavity into which the fourth-instar lateral palatal brush filaments grow as cytoplasmic extensions. On reaching their final length, the filaments deposit cuticulin, inner epicuticle, and procuticle sequentially on their outer surfaces. The lateral palatal crossbars, on which the lateral palatal brush filaments insert, form after filament development is complete. At the beginning of development, the organelles involved in plasma membrane and cuticle production are located at the base and middle of the cells. As the filament rudiments grow, most rough endoplasmic reticulum, mitochondria, and Golgi apparatus move to the apex of the epidermal cells and into the filament rudiments. After formation of the lateral palatal brush filaments and lateral palatal crossbars, extensive organelle breakdown occurs. Lateral palatal brush formation is unusual in that no digestion and resorption of old endocuticle occurs prior to deposition of new cuticle. No mucopolysaccharide secretion by the lateral palatal brush epidermis was observed, nor were muscle fibres observed to attach to the lateral palatal crossbars, as has been suggested by other workers.


2019 ◽  
Vol 40 (Supplement_1) ◽  
Author(s):  
L Hille ◽  
T Nuehrenberg ◽  
M Lenz ◽  
A Vlachos ◽  
D Trenk

Abstract Reticulated platelets (RP) are the youngest circulating platelets in blood. Compared to older platelets, RP represent a highly active prothrombotic platelet population associated with an increased risk for cardiovascular events, mortality and impaired response to antiplatelet drugs compared to older platelets (non-RP). The underlying mechanisms for these characteristics of RP are so far poorly understood. This study aimed to characterize ultrastructural properties of RP and non-RP by transmission electron microscopy (TEM) of FACS-sorted human platelets using a novel staining method for RP. Washed platelets from three healthy donors were stained by SYTO™13, a nucleic acid binding fluorescent dye, which enables determination of RP and non-RP based on their RNA-content. 8×106 platelets were fixed, sorted and sandwiched between two layers of agarose gel. Samples were further processed for visualization by TEM. In total, 1047 platelets, i.e., electron micrographs of individual cross-sections, were analysed by an investigator blinded concerning experimental condition. Sizes, numbers of α-granules, dense granules, mitochondria and open canalicular system openings were assessed in RP and non-RP, respectively. Furthermore, platelets were screened for pseudopodia formation as an indicator for activation. Cross-sectional area was significantly different between RP and non-RP (2.44 [1.80–3.22] vs. 1.34 [1.04–1.89] μm2; p<0.0001; median with IQR). α-granule and mitochondria amounts were higher in RP which persisted even after adjustment for platelet size (α-granules: 4.64 [3.46–5.86]/μm2 vs. 4.15 [2.87–5.26]/μm2; p<0.0001; mitochondria: 0.33±0.02 /μm2 vs. 0.12±0.01/μm2; mean ± SEM). In contrast, the amount of open canalicular system openings per square μm was higher in the non-RP group (5.82 [4.34–7.68] /μm2 vs. 5.52 [4.01–7.11] /μm2; p=0.009). Dense granule content per square μm was similar in both RP and non-RP. Pseudopodia were present in 38% (RP) respective 37% (non-RP) of platelets. Notably, golgi apparatus and rough endoplasmic reticulum which are rarely seen in platelets were detected in several RP. Analysis of TEM pictures revealed an almost 2-fold higher cross-sectional area in RP compared to non-RP. Even after adjustment for differences in size, α-granule content remained significantly higher in RP indicating a higher storage pool for prothrombotic constituents like p-selectin or von Willebrand factor. Although the relative amount of dense granules per area did not differ between the two groups, a higher absolute number of dense granules per platelet in the RP group is indicative for higher amounts of stored small molecules such as ADP, calcium or serotonin. Despite the anucleate nature of platelets, the presence of golgi apparatus and rough endoplasmic reticulum suggests the capability of protein biosynthesis in RP. These comprehensive findings provide new important insight into the ultrastructural properties of human RP. Acknowledgement/Funding PharmCompNet Baden-Württemberg: Kompetenznetzwerk Pharmakologie Baden-Württemberg


1973 ◽  
Vol 37 (6) ◽  
pp. 972-976 ◽  
Author(s):  
G. A. MEDEIROS-NETO ◽  
S. P. A. TOLEDO ◽  
A. A. PUPO ◽  
M. S. SUCUPIRA ◽  
F. FRAIGE-FILHO ◽  
...  

Author(s):  
R. A. Turner ◽  
A. E. Rodin ◽  
D. K. Roberts

There have been many reports which establish a relationship between the pineal and sexual structures, including gonadal hypertrophy after pinealectomy, and gonadal atrophy after injection of pineal homogenates or of melatonin. In order to further delineate this relationship the pineals from 5 groups of female rats were studied by electron microscopy:ControlsPregnant ratsAfter 4 weekly injections of 0.1 mg. estradiol benzoate.After 8 daily injections of 150 mcgm. melatonin (pineal hormone).After 8 daily injections of 3 mg. serotonin (melatonin precursor).No ultrastructural differences were evident between the control, and the pregnancy and melatonin groups. However, the estradiol injected animals exhibited a marked increase in the amount and size of rough endoplasmic reticulum within the pineal cells.


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