INABILITY OF ADENOSINE 3\m='\:5\m='\-CYCLIC MONOPHOSPHATE TO SIMULATE FULLY THE EFFECTS OF LH IN RABBIT OVARIES

Luteinizing hormone has a key r\l=o^\lein promoting the synthesis of progesterone(Savard, Marsh & Rice, 1965) and in the induction of ovulation (Moudgal, Macdonald & Greep, 1971). The steroidogenic effect of LH is believed to be exercised through adenosine 3\m='\:5\m='\-cyclicmonophosphate (Marsh, Butcher, Savard & Sutherland, 1966). The hormone stimulates the adenyl cyclase activity of corpus luteum preparations in vitro (Marsh, 1970; C. Das, G. P. Tal-war and A. Haksar, unpublished studies). Furthermore, adenosine 3\m='\:5\m='\-cyclic monophosphate (cAMP), if added to the medium, simulates the action ofLH for increased production of progesterone from endogenous substrates (Marsh & Savard, 1966; Dorrington & Kilpatrick, 1967). Although there is no direct evidence available to conclude that cAMP can mimic the action of LH in induction of ovulation, Rondell (1970) has reported the ability of LH, cAMP or progesterone to increase the distensibility of the follicular wall in strips maintained in tissue culture. The object of the experiments communicated in this paper was to investigate whether cAMP can fully replace LH for the induction of ovulation in mammal