Effects of estrogen, glucocorticoid, glucagon, and adenosine 3':5'-monophosphate on catalytic activity, amount, and rate of de novo synthesis of hepatic histidase.

C A Lamartiniere,M Feigelson

doi:10.1016/s0021-9258(17)40376-0

Abstract

The mechanisms by which estrogen, glucocorticoid, glucagon, and adenosine 3':5'-monophosphate (cAMP), regulators which participate in the postnatal development of rat liver histidase, elevate the catalytic activity of this enzyme have been explored. A monospecific antibody against homogeneously purified preparations of rat liver histidase has been elaborated in the goat. Employing this antibody in immunotitration experiments, it has been demonstrated that the elevations of hepatic histidase activity elicited by administration in vivo of estradiol-17beta, cortisol acetate, glucagon, and N6,O2'-dibutyryl adenosine 3':5'-monophosphate (dibutyryl cAMP) are paralleled, in each instance, by equivalent increments in immunoprecipitable histidase protein. Following administration of each of the three hormones and dibutyryl cAMP, rates of [14C]leucine incorporation in vivo into rat liver histidase, isolated by immunoprecipitation, relative to incorporation rates into total soluble hepatic protein, increase in magnitudes which are comparable to increases in enzyme amount and catalytic activity. It is thus inferred that estrogen, glucocorticoids, and glucagon, via cAMP, each regulate rat liver histidase development at specific postnatal stages by inducing increases in histidase biosynthetic rates.

Highlights

(CAMP), regulators which participate in the postnatal development of rat liver histidase, elevate the catalytic activity of this enzyme have been explored
We have explored the mechanisms by which estrogen, glucocorticoid, and glucagon, as well as CAMP effectuate increases in hepatic histidase catalytic activity
That elevations in catalytic activity of rat liver histidase elicited by estradiol-17B, cortisol acetate, glucagon, and dibutyryl CAMP are each accompanied by equivalent increments in quantities of immunologically identical enzyme protein has been demonstrated by immunotitration experiments, in which identical equivalence points were observed and equal quantities of protein per unit of catalytic activity were immunoprecipitated

Summary

Introduction

(CAMP), regulators which participate in the postnatal development of rat liver histidase, elevate the catalytic activity of this enzyme have been explored. Hepatic L-histidine ammonia-lyase (histidase, EC 4.3.1.3) of the rat undergoes a complex postnatal developmental course, in which its catalytic activity initially appears shortly following parturition and subsequently rises in a multiphasic sexspecific fashion, resulting in enzyme levels which are considerably higher in the adult female than the male [1, 2] Reports from this and other laboratories suggest that this developmental course is the resultant of concerted action of a number of hormones and nutritional factors acting at strategic stages, some of which elevate enzyme activity (e.g. estrogen, glucocorticoid, glucagon via CAMP [3,4,5,6,7], and amino acids [4, 5, 8, 9]) and others of which suppress histidase activity (e.g. pituitary components (10, 111, androgen (121, and thyroxine [13, 14]). Grant Health vides a valuable model for investigation of biochemical mechanisms underlying hormonal regulation of enzymes in differentiating tissues

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Conclusion