A cDNA encoding the potential activin βC subunit was produced from human testis RNA using reverse transcription and PCR and then used as a probe in Northern blot analysis of poly(A)+ RNA. A transcript of ∼1·8 kb was evident in human ovary, placenta and testis samples. A transcript of this size was also detected in adult rat caput and cauda epididymis, and adult and day-15 testis and adult spleen, while adult liver contained a single transcript of ∼2·1 kb. Poly(A)+ RNA from primary spermatocytes but not from round spermatids contained the 1·8kb activin βC mRNA. These findings highlight the need for further studies to determine the physiological role(s) of activin βC in a wide variety of tissues.