Suppression of Luteinizing Hormone and Testosterone Secretion in Bulls Following Adrenocorticotropin Hormone Treatment1

Abstract

The present investigation was conducted to evaluate the inhibitory effects of adrenal corticosteroids on testosterone production by the bull testis. Administration of a single i.v. dose of ACTH (80 IU) resulted in a corticosteroid peak which lasted .apprx. 6 h. During this 6 h period, no episodic increases in secretion of LH [luteinizing hormone] or testosterone were initiated and basal concentrations of testosterone were suppressed (P < 0.05) below control values. Episodic secretion of LH and testosterone resumed 6-7 h after ACTH when concentrations of serum corticosteroids had returned to basal levels. Apparently, ACTH-induced increases in serum corticosteroids suppress the episodic secreiton of LH, resulting in a suppresion of testosterone secretion by the bull testis.