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Human mutation affecting hormone-sensitive adenylate cyclase
Progress in Clinical and Biological Research
|January 1, 1981
Summary
Partial deficiency of a key adenylate cyclase protein was found in some pseudohypoparathyroidism (PHP) patients. This guanine nucleotide regulatory protein reduction may serve as a biochemical marker for PHP and explain hormone resistance.
Area of Science:
- Biochemistry
- Endocrinology
- Molecular Biology
Background:
- Hormone-sensitive adenylate cyclase requires a specific protein for cyclic AMP synthesis.
- Pseudohypoparathyroidism (PHP) is characterized by hormone resistance.
Purpose of the Study:
- To investigate the role of the adenylate cyclase protein component in pseudohypoparathyroidism (PHP).
- To determine if deficiency in this protein is a biochemical marker for PHP patients.
Main Methods:
- Assessed biochemical activity of the adenylate cyclase protein in erythrocyte membranes.
- Measured susceptibility to radiolabeling using 32P-NAD and cholera toxin in PHP patients.
Main Results:
- Four out of ten PHP patients showed a 50% reduction in the adenylate cyclase protein.
- This reduction correlated with the full spectrum of skeletal abnormalities in PHP.
- The remaining six PHP patients had normal protein levels.
Conclusions:
- Partial deficiency of the guanine nucleotide regulatory protein is a biochemical marker for a subset of PHP patients.
- This deficiency may explain target organ resistance to hormones in PHP.