Effect of transglutaminase substrates and polyamines on the cellular sequestration and processing of follicle-stimulating hormone by rat Sertoli cells
Transglutaminase (TGase) substrates monodansyl cadaverine (MDC, monodansyl-1,5 diaminopentane) and methylamine (MA) and polyamines (PA) were tested for their effects on the cellular processing of radioiodinated human follicle-stimulating hormone (/sup 125/I-hFSH). Specifically bound /sup 125/I-hFSH that could be released from cells during 10-min incubation period with acidified (pH 3.9) Hanks balanced-salt solution was considered membrane-bound unsequestered hormone. The rate at which cells sequestered /sup 125/I-hFSH into cellular compartments resistant to acid dissociation depended on the length of time in which cells were incubated with hormone. Cells incubated with /sup 125/I-hFSH for 15, 60, and 120 min had half-lives of sequestration of 26, 55 and 67 min respectively. One hundred-micromolar MDC inhibited degradation of /sup 125/I-hFSH as measured by the presence of radioactivity in the medium that was soluble in trichloroacetic acid. The rate of sequestration was never slower than that of controls, indicating that MDC did not decrease the ability of Sertoli cells to sequester /sup 125/I-hFSH. Despite these two observations, radioactivity associated with cells (acid-resistant radioactivity) was lower in cells treated with MDC than in controls. No effect of MDC on specific binding of 125I-hFSH was observed. Similar results were observed with MA, albeit at higher levels (0.0025-0.0425 M), consistent with their relative potency to inhibit TGase activity. Polyamines, spermine, and putrescine also decreased cell-associated radioactivity despite decreasing degradation of hFSH. TGase substrates (MDC, MA, PA) prevented entry of sequestered 125I-hFSH into the degradative pathways of Sertoli cells. These data suggest that transglutamination may influence the fate of sequestered FSH in Sertoli cells but not the rate at which sequestration occurs.
- Research Organization:
- Albany Medical College, New York, NY
- OSTI ID:
- 5013624
- Journal Information:
- Biol. Reprod.; (United States), Vol. 1
- Country of Publication:
- United States
- Language:
- English
Similar Records
Internalization and degradation of human chorionic gonadotropin in ovine luteal cells: Kinetic studies
Effects of lysosomal inhibitors on /sup 125/I-insulin and /sup 125/I-asialofetuin degradation by the isolated, perfused rat liver and isolated rat hepatocytes
Related Subjects
FSH
BIOCHEMICAL REACTION KINETICS
METHYLAMINE
BIOLOGICAL EFFECTS
AMINES
CADAVERINE
CELL CULTURES
ESTRADIOL
IODINE 125
LABELLED COMPOUNDS
POLYMERS
RADIOIMMUNOASSAY
RATS
TRACER TECHNIQUES
ANIMALS
BETA DECAY RADIOISOTOPES
DAYS LIVING RADIOISOTOPES
ELECTRON CAPTURE RADIOISOTOPES
ESTRANES
ESTROGENS
GONADOTROPINS
HORMONES
HYDROXY COMPOUNDS
IMMUNOASSAY
IMMUNOLOGY
INTERMEDIATE MASS NUCLEI
IODINE ISOTOPES
ISOTOPE APPLICATIONS
ISOTOPES
KINETICS
MAMMALS
NUCLEI
ODD-EVEN NUCLEI
ORGANIC COMPOUNDS
PEPTIDE HORMONES
PITUITARY HORMONES
RADIOASSAY
RADIOIMMUNOLOGY
RADIOISOTOPES
REACTION KINETICS
RODENTS
STEROID HORMONES
STEROIDS
VERTEBRATES
550201* - Biochemistry- Tracer Techniques