title: Effect of hormones and cyclic AMP on gamma-glutamyltranspeptidase activity of rat mammary gland explants.
abstract: gamma-Glutamyl transpeptidase activity was assayed in midpregnant rat mammary gland explants at 14, 22 and 38 h, in the presence and absence of insulin, prolactin and corticosterone. With these 3 hormones the explants attained the characteristics of a secretory gland after 22 h of tissue culture, at which time the enzyme exhibited its maximal activity. The addition of dibutyryl cyclic AMP in the presence of the 3 hormones produced a significant increase in enzyme activity, which was maximal with a 1 mM concentration of the cyclic nucleotide. A similar effect was observed when theophylline or theophylline plus dibutyryl cyclic AMP were added to the culture medium.
mesh_terms: D000818:Animals; D003994:Bucladesine / Q000494:pharmacology; D003345:Corticosterone / Q000494:pharmacology; D005260:Female; D007328:Insulin / Q000494:pharmacology; D008321:Mammary Glands, Animal / Q000201:enzymology*; D011388:Prolactin / Q000494:pharmacology; D051381:Rats; D013806:Theophylline / Q000494:pharmacology; D005723:gamma-Glutamyltransferase / Q000378:metabolism*
chemical_list: D007328:Insulin; D003994:Bucladesine; D011388:Prolactin; D013806:Theophylline; D005723:gamma-Glutamyltransferase; D003345:Corticosterone