The incorporation of [3H]glucosamine, [3H]fucose and [14C]mannose into protein in the rat anterior pituitary incubated in vitro

Todd, Jean; Samli, Marcqueta H.

doi:10.1016/0304-4165(73)90044-5

Cited by 17 publications

(5 citation statements)

References 22 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…In contrast, a significant percentage of [3H]fucose-containing glycoproteins were released at 4 hr ( Table I). The value observed in the present study is quite comparable to that observed by Todd and Samli (6). Thus, the processes involved in glycoprotein biosynthesis by rat anterior pituitary tissue appear to be consistent with those reported for other tissues (8) and those obtained with rat and bovine pituitary-derived cell-free systems (3)(4)(5).…”

Section: -( B -H ) G a L A C T O S E (Sci/rnrnol) supporting

confidence: 94%

Temporal Pattern of Incorporation of 3H Precursors into Pituitary Glycoproteins and Their Subsequent Release

Grotjan¹

1982

Experimental Biology and Medicine

View full text Add to dashboard Cite

The temporal pattern of incorporation of various 3H precursors into glycoproteins by rat anterior pituitaries incubated in vitro and the release of 3H-glycoproteins was examined. [3H]Leucine incorporation was linear with respect to time and [3H]leucinecontaining macromolecules appeared in the media in about 1 hr. The temporal pattern of [3H]mannose incorporation and release was similar to that observed for [3H]leucine consistent with [3H]mannose incorporation via the chitobiose core. [3H]Galactose and [3H]fucose were incorporated after apparent time delays of approximately 15 min and soon thereafter (20-25 min) appeared in the medium in 3H-glycoproteins. Thus, these precursors appear to be added as terminal residues. [3H]Glucosamine exhibited a pattern intermediate between [3H]leucine and [3H]fucose whereas [3H]GlcNAc appeared to be incorporated as a terminal residue. 452

show abstract

Section: -( B -H ) G a L A C T O S E (Sci/rnrnol) supporting

confidence: 94%

Temporal Pattern of Incorporation of 3H Precursors into Pituitary Glycoproteins and Their Subsequent Release

Grotjan¹

1982

Experimental Biology and Medicine

View full text Add to dashboard Cite

show abstract

“…As previously observed in hepatocytes (Bennett and Leblond, 1971), duodenal (Bennett and Leblond, 1970), and thyroid cells (Haddad et al, 1971), the [aH]fucose was incorporated directly into the Golgi apparatus in both somatotrophs and gonadotrophs after intravenous injection of the labeled sugar. Todd and Samli (1973) had observed that inhibition .of protein synthesis by puromycin for 45 min did not affect the incorporation of fucose into glycoproteins of rat adenohypophysis. These observations and the present findings strongly suggest that fucose, a terminal sugar of glycoproteins (Spiro, 1970), is added to preformed polypeptide chains which have already migrated to the Golgi apparatus in the somatotroph and the gonadotroph.…”

Section: Discussionmentioning

confidence: 99%

“…The radioactivity found in the extracellular space could belong to some glycoproteins present in the fibrillar extracellular material or could be related to some release processes, for example, the release of glycoprotein hormones. Todd and Samli (1973) have reported that 4% of all fucose-labeled proteins were released into the incubation medium 30 rain after the incorporation of the labeled sugar.…”

Section: Discussionmentioning

confidence: 99%

“…and duodenal cells Leblond, 1970, 1971), fucose is incorporated into glycoproteins in the Golgi apparatus. In rat anterior pituitary in vitro, incorporation of mannose and glucosamine into total glyeoproteins was prevented by puromycin within 30 rain whereas the addition of puromycin to the incubation medium did not decrease fucose incorporation before 45 rain of incorporation (Todd and Samli, 1973). In the stimulated thyrotrophs (thyroidectomy cells) of the rat adenohypophysis, fucose was found to be incorporated directly in both the rough endoplasmic reticulum (ER) and the Golgi apparatus (Pelletier and Puviani, 1973).…”

mentioning

confidence: 99%

See 1 more Smart Citation

Autoradiographic Studies of Synthesis and Intracellular Migration of Glycoproteins in the Rat Anterior Pituitary Gland

Pelletier

1974

The Journal of Cell Biology

View full text Add to dashboard Cite

The incorporation of [aH]fucose in the somatotrophic and gonadotrophic cells of the rat adenohypophysis has been studied by electron microscope autoradiography to determine the site of synthesis of glycoproteins and to follow the migration of newly synthesized glycoproteins. The pituitaries were fixed 5 rain, 20 rain, 1 h, and 4 h after the in vivo injection of pH]fucose and autoradiographs analyzed quantitatively. At 5 rain after [~H]fucose administration, 80-90% of the silver grains were localized over the Golgi apparatus in both somatotrophs and gonadotrophs. By 20 min, the Golgi apparatus was still labeled and some radioactivity appeared over granules. At 1 h and 4 h, silver grains were found predominantly over secretory granules. The kinetic analysis showed that in both protein-secreting ceils (somatotrophs) and glycoprotein-secreting cells (gonadotrophs), the glycoproteins have their synthesis completed in the Golgi apparatus and migrate subsequently to the secretory granules. It is concluded from these in vivo studies that glycoproteins which are not hormones are utilized for the formation of the matrix and/or of the membrane of the secretory granules. The incorporation of [3H]fucose in gonadectomy cells (hyperstimulated gonadotrophs) was also studied in vitro after pulse labeling of pituitary fragments in medium containing [aH]fucose. The incorporation of [3H]fucose was localized in both the rough endoplasmic reticulum (ER) and the Golgi apparatus. Later, the radioactivity over granules increased while that over the Golgi apparatus decreased. The concentration of silver grains over the dilated cisternae of the rough ER was not found to be modified at the longest time intervals studied.Recent work on the synthesis of glycoproteins has demonstrated that the different sugars are added step by step to the preformed polypeptide chains, according to their position in the lateral side chains. Studies on the synthesis of thyroglobulin (Spiro and Spiro, 1966;Herscovics, 1969Herscovics, , 1970 and immunoglobulin (Swenson and Kern, 1968;Melchers, 1970; Schenken and Uhr, 1970) have shown that whereas glucosamine and mannose are incorporated during synthesis of the polypeptide chains, the terminal sugars, e.g., fucose, are added after the completion of the polypeptide backbone. Autoradiographic data have also shown that in thyroid cells (Haddad et al

show abstract

“…(2) After addition of 3H-leucine to immunoglobulin-M-secreting lymphocytes, a lag of 1 h was necessary before labeled immunoglobulin M appeared in the medium, even though intracellular immunoglobulin M was labeled immediately [1], Since the carbohydrate structure of immunoglobulin M is of the same type as in hCG [23], similar production times of both glycoproteins might be expected. (3) Glucosamine-or mannose-labeled glycoprotein was barely detectable in the medium after a 30-to 60-min incubation of rat anterior hemipituitaries, whereas uptake and incorporation into intracellular pro tein was rapid [26]. The anterior pituitary synthesizes 3 glycoprotein hor mones -LH, FSH, and TSH -structurally related to hCG [2].…”

Section: Discussionmentioning

confidence: 99%

Early Stimulation of Human Chorionic Gonadotropin Secretion by Dibutyryl Cyclic AMP and Theophylline in Human Malignant Trophoblast Cells <i>in vitro</i>: Inhibition by Actinomycin D, α-Amanitin, and Cordycepin

Ra¹,

Hussa²

1975

Gynecol Obstet Invest

View full text Add to dashboard Cite

Human malignant trophoblast cells (BeWo line) in culture were employed to investigate the early stimulation of human chorionic gonadotropin (hCG) secretion by 1 mM dibutyryl cyclic AMP and 1 mM theophylline (dbT). The earliest increase in secreted immunoreactive hCG occurred at least 3½ h following addition of dbT, and was preceded by an increase in intracellular hCG. These results suggested that dbT stimulated hCG synthesis, rather than release. Addition of either 0.062 µg/ml actinomycin D or 100 µg/ml cordycepin along with dbT, or 3 µg/ml Α-amanitin 9 h prior to addition of dbT, prevented the increase in hCG secretion at 3½–8 h. It was concluded that synthesis of RNA (possibly messenger RNA) is required for the early stimulation of hCG secretion by dbT.

show abstract

The incorporation of [3H]glucosamine, [3H]fucose and [14C]mannose into protein in the rat anterior pituitary incubated in vitro

Cited by 17 publications

References 22 publications

Temporal Pattern of Incorporation of 3H Precursors into Pituitary Glycoproteins and Their Subsequent Release

Temporal Pattern of Incorporation of 3H Precursors into Pituitary Glycoproteins and Their Subsequent Release

Autoradiographic Studies of Synthesis and Intracellular Migration of Glycoproteins in the Rat Anterior Pituitary Gland

Early Stimulation of Human Chorionic Gonadotropin Secretion by Dibutyryl Cyclic AMP and Theophylline in Human Malignant Trophoblast Cells <i>in vitro</i>: Inhibition by Actinomycin D, α-Amanitin, and Cordycepin

Contact Info

Product

Resources

About