title: Rabbit ovarian protein kinases. I. Effect of an ovulatory dose of human chorionic gonadotropin or luteinizing hormone on the subcellular distribution of follicular and luteal protein kinases.
abstract: Studies on the subcellular distribution of protein kinase activity in popped estrous follicles from rabbit ovaries revealed that 15% of the total cellular protein kinase activity was compartmentalized in the nuclear, mitochondrial, and microsomal fractions. About 50% of the particulate protein kinase activity was unaffected by the heat-stable protein kinase inhibitor and was thus cAMP-independent. The majority of cellular protein kinase activity was identified in the 105,000 X g supernatant fraction as cAMP-dependent. hCG- or coital-induced ovulation and subsequent corpus luteum (CL) formation, and hCG-induced luteal regression promoted changes and a redistribution of protein kinase activity among the subcellular fractions. In follicles, hCG promoted a transient decline of nuclear protein kinase activity as well as transient increases of the relative amount of protein kinases localized in the microsomal fractions before ovulation. In CL induced by a fertile mating, the specific activity as well as the total amount of protein kinases in the nuclear fraction were reduced 2-fold. Mitochondrial protein kinase activity from CL of pseudopregnancy and pregnancy was reduced 2-fold. The relative amount of protein kinase activity in microsomes of CL was increased 2-fold, but the specific activity was not affected. hCG-induced luteal regression resulted in a transient decline of the nuclear protein kinase activity in CL of 4-day pseudopregnant rabbits. In interstitial tissue, the specific activity of the nuclear protein kinase was increased over luteal levels, the mitochondrial-specific protein kinase remained at the reduced luteal levels, and the microsomal and cytosol protein kinase specific activities increased 2-fold. Studies with the heat-stable protein kinase inhibitor revealed that the hCG- or coital-induced redistribution of intracellular protein kinase affected both the cAMP-dependent and cAMP-independent activity to a similar degree and no changes of the relative distribution of cAMP-dependent vs. cAMP-independent activity were observed. These results indicate that the intracellular distribution and enzymatic activity of cAMP-dependent protein kinases in ovarian structures are subject to regulation by LH (hCG) and depend upon the various reproductive stages of the rabbit.
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D003338:Corpus Luteum / Q000187:drug effects / Q000201:enzymology*; D000242:Cyclic AMP / Q000494:pharmacology; D006152:Cyclic GMP / Q000494:pharmacology; D004789:Enzyme Activation; D005260:Female; D007700:Kinetics; D007986:Luteinizing Hormone / Q000494:pharmacology*; D006080:Ovarian Follicle / Q000187:drug effects / Q000201:enzymology*; D010053:Ovary / Q000201:enzymology*; D010060:Ovulation / Q000187:drug effects*; D011494:Protein Kinases / Q000378:metabolism*; D011817:Rabbits; D013347:Subcellular Fractions / Q000201:enzymology
chemical_list: D006063:Chorionic Gonadotropin; D007986:Luteinizing Hormone; D000242:Cyclic AMP; D011494:Protein Kinases; D006152:Cyclic GMP