Adenylate cyclase regulation in the spermatogenic cell plasma membrane: Modulating effects of TPA and TCDD
This research was designed to compare the effects of TPA, a phorbol ester, and TCDD in a spermatogenic cell population, a target of TCDD toxicity. Membrane-bound adenylate cyclase activity was used an index of membrane function, and was quantified by the amount of {sup 32}P-cAMP formed from {sup 32}P-ATP following chromatographic separation. Exposure to male germ cells in-vitro to TPA and TCDD followed by direct measurement of enzyme activity was used to investigate the potential of each agent to perturb membrane function. TPA and TCDD consistently inhibited adenylate cyclase activity at the levels of G{sub s}-catalytic unit coupling and hormone-receptor activation, as measured by the stimulation of enzyme activity by concomitant addition of forskolin and GTP and FSH and GTP, respectively. The effect on coupling required at least 60 minutes of exposure to TPA or TCDD. Concentration-response curves demonstrated a progressive desensitization with increasing TPA concentration, while TCDD exhibited consistent inhibition over the same concentration range.
- Research Organization:
- Philadelphia Coll. of Pharmacy and Science, PA (USA)
- OSTI ID:
- 6516805
- Resource Relation:
- Other Information: Thesis (Ph. D.)
- Country of Publication:
- United States
- Language:
- English
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59 BASIC BIOLOGICAL SCIENCES
CYCLASES
ENZYME ACTIVITY
DIOXIN
TOXICITY
PHORBOL ESTERS
SPERMATOGONIA
SENSITIVITY
AMP
ATP
CELL MEMBRANES
CHROMATOGRAPHY
COMPARATIVE EVALUATIONS
DOSE-RESPONSE RELATIONSHIPS
INHIBITION
PHOSPHORUS 32
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARCINOGENS
CELL CONSTITUENTS
DAYS LIVING RADIOISOTOPES
ENZYMES
ESTERS
GAMETES
GERM CELLS
HETEROCYCLIC COMPOUNDS
ISOTOPES
LIGHT NUCLEI
LYASES
MEMBRANES
NUCLEI
NUCLEOTIDES
ODD-ODD NUCLEI
ORGANIC COMPOUNDS
ORGANIC OXYGEN COMPOUNDS
PHOSPHORUS ISOTOPES
RADIOISOTOPES
SEPARATION PROCESSES
560300* - Chemicals Metabolism & Toxicology
550501 - Metabolism- Tracer Techniques