Robert Pittman, one of the founders and...

Robert Pittman, one of the founders and guiding forces of MTV Networks, plans to form a number of media joint ventures with Viacom International Inc., which purchased MTV last year.

Viacom said Thursday that the first joint venture is expected to be a new record label with MCA Records in which Viacom will participate. But no details of the planned ventures were released.

Pittman, 33, will continue in his position as MTV Network’s chief executive until at least the end of the year and may possibly remain on until mid-1987, depending on the timing of the ventures, according to Viacom.

A former radio programing executive, Pittman joined Warner Amex Satellite Entertainment in 1980, and he helped created the pioneering 24-hour rock-video cable-TV service that was launched in August, 1981.

Warner Amex, a joint venture of Warner Communications and American Express, sold a one-third stake in MTV to the public in 1984. A year later, Pittman was among a group of MTV executives that made an unsuccessful attempt to take the company private again through a leveraged buyout financed by Forstmann, Little & Co.