Defect of human growth hormone receptors in the liver of two patients with Laron-type dwarfism.

Liver microsome pellets prepared from tissue obtained by elective open biopsy from two patients (aged 4 and 26 years) with Laron-type dwarfism (LTD) showed no specific binding of 125I-hGH (human growth hormone). In contrast, 31 assays of liver microsomes obtained immediately after clinical death from 6 healthy subjects (kidney transplantation donors with a mean age of 24 years) showed a mean specific binding of 14% (range 7.9 to 24%). We interpreted these findings as evidence that in patients with LTD there is a defect in the hGH receptors of the liver and a consequent lack of somatomedin generation. The fact that the liver microsomes from the two LTD patients showed active specific binding of 125I-insulin suggest that, in this syndrome, it is only the receptors for hGH that are defective.