G. ALIBERTI¹, I. PULIGNANO¹, M. PROIETTA¹, F. MIRALDI²,
L. CIGOGNETTI², L. TRITAPEPE², C. DI GIOVANNI², R. ARZILLA²,
E. VECCI¹, M. TOSCANO²

¹Department of Clinical Science and ²Institute "Chirurgia del Cuore e dei Grossi Vasi", University of Rome "La Sapienza", Rome, Italy

Received February 21, 2000
Accepted September 21, 2000

Summary
We measured hormonal levels in blood samples from pulmonary and radial arteries in 117 patients undergoing aorto-coronary by-pass surgery with the aim of investigating the role of the pulmonary vessel endothelium in hormone metabolism. Insulin and glucagon concentrations were significantly higher in pulmonary artery blood with respect to radial artery blood (73±65 vs. 65±47 pmol/l, p<0.005, and 80+49 vs. 73+51 ng/l, p<0.01, respectively), while no difference was found for growth hormone, prolactin, C peptide, insulin-like growth factor I, follicle stimulating hormone, luteinizing hormone, thyroid stimulating hormone, parathyroid hormone, thyroglobulin, triiodothyronine, thyroxine, free triiodothyronine, and free thyroxine. Moreover, prolactin concentrations were more than twice the normal levels, this being an effect of propafol and the opiate fentanyl used for the general anesthesia. Assuming that the arteriovenous differences observed are a marker of peptide hormone degradation, our study has demonstrated that with similar kinetics insulin and glucagon secreted into portal circulation and escaping from hepatic extraction undergo further homeostatic removal of about 9-10 % in the pulmonary circulation before entering the general circulation.

Key words
Peptide hormones · Thyroid hormones · Endothelial cleavage · Lung · Insulin · Glucagon · Peptide degradation

Reprint requests
Prof. Giuseppe Aliberti, Dipartimento di Scienze Cliniche, Policlinico Umberto I, Viale del Policlinico, 00161 Roma, Italy.

ISSN 0862 - 8408