Increased plasma concentration of epidermal growth factor in female patients with non-toxic nodular goitre

Objective: Epidermal growth factor (EGF) is believed to be one of the most potent growth factors for the thyroid gland. Design and methods: We tested plasma EGF concentrations (radioreceptor method) in patients with nontoxic nodular goitre (NNG). Blood samples from patients with NNG were collected on the day before the surgery, during subtotal thyroidectomy (sTx) - from peripheral and thyroid veins, on the 3rd day after sTx, 3 months after sTx, and 9 months after the surgery. Results: Before the operation, the mean plasma EGF concentration in 50 women with NNG was significantly higher (1.16 +/- 0.69 ng/ml: mean +/- S.E.) than that in 32 control female patients subjected subsequently to other (non-thyroid) operations (0.41 +/- 0.27 ng/ml; P < 0.001), and that in 20 healthy women (0.35 +/- 0.11 ng/ml: P < 0.001), both of which groups were without goitre or had a small non-toxic diffuse goitre. The surgical treatment of NNG resulted in a significant reduction in plasma EGF 3 months after sTx (0.56 +/- 0.22 ng/ml). A further slight decrease was observed 9 months after sTx (0.44 +/- 0.14 ng/ml). Conclusions: Our observations confirm the assumption that EGF may participate in the process of goitre formation in human subjects. However. the source of EGF involved in this process remains unclear. Some findings could suggest that plasma EGF, which was increased in patients with NNG, map be of non-thyroid origin: however, the majority of our observations strongly stress the significance of an intact thyroid in the preservation of an unchanged EGF value, suggesting a role of locally produced EGF in the pathogenesis of NNG.