Human chorionic gonadotropin (hCG) is a peptide hormone, whose one of the structural subunits is identical to that of thyroid-stimulating hormone (TSH). As a consequence, the receptors of TSH also act as receptor for hCG hormone. Keeping in mind this interesting property of hCG we have studied the complex formation ability of various no-carrier-added Β-emitting isotopes of 61Cu (3.3h), 62Zn (9.2h), 90Nb (14.60h) and 99Mo (66.02h) with hCG molecule. Stability of the hCG-M (M=metal ions) complexes was investigated by dialysis with respect to triple distilled water and ringer lactate solution, which has the same composition as extracellular fluid. © 2010 Elsevier Ltd.